Wikipedia:Reference desk/Science

Reference Desk

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June 12

Headset adapter question

I'm interested in using an Altec 502i headset (designed for a computer, link here [1]) with my telephones. The product description on amazon says that I would need an "adapter", but it doesn't say what kind of adapter. What kind of adapter would I need? A link to an amazon.com item would be perfect. Thanks! -- Creidieki 01:32, 12 June 2006 (UTC)

It depends mostly on your telephones. Some mobile phones have 2.5mm jacks, which look just like the standard 3.5mm audio jacks, but obviously are a bit smaller. This would be all you need.

Seizures and blood pressure

tyring to find info on seizures related to sudden blood pressure increse or decrease [unsigned]

• If we had more information, it might be at hypertensive encephalopathy or malignant hypertension, but I looked and there's not much there on seizures. They might be useful as search terms in Google, though. That's for seizures due to high blood pressure; for low blood pressure you might try ischemic encephalopathy. - Nunh-huh 12:48, 13 June 2006 (UTC)

Hypertensive encephalopathy is a redlink, as is ischemic encephalopathy. It appears we only have encephalopathy, which doesn't really answer the question. The sudden fall in blood pressure that accompanies a vasovagal syncope, is often accompanied by seizures. This is a normal reaction that can be triggered by anxiety. I've seen people who are afraid of the sight of blood, doing this when coming to have a blood sample taken, before venipuncture. It does not indicate any underlying brain pathology. --vibo56 ^talk 13:55, 17 June 2006 (UTC)

moon

wats the scientific reason behind the increasing n decreasing shades of moon???

Lunar cycle -- Миборовский 04:05, 12 June 2006 (UTC)

Insect question

Many insects like moths are attracted to light. This could present a major problem if moths develop to the point that they drive automobiles, as two moths driving in opposing directions would be drawn towards each other's headlights resulting in a head-on collision. What steps have been made to prevent this potential tragity? Mayor Westfall 04:16, 12 June 2006 (UTC)

Members of arthropoda were actually a highly-evolved, starfaring civilization that was unfortunately wiped out by a doomsday device they created when a hapless mechanic got too enamored by the blinking lights on it and pressed the start button. Unfortunately, the stop button was not illuminated. -- Миборовский 04:23, 12 June 2006 (UTC)

There is no problem. The moths will be attracted to the light, but the cars won't be, so the moths will leap out the window to their deaths, and the cars will float harmlessly into the ultra-rubber road barriers.  freshofftheufoΓΛĿЌ  05:47, 12 June 2006 (UTC)

Did you read our article on moth? They would only circle each other.--Shantavira 07:37, 12 June 2006 (UTC)

Wouldn't they crash into each other while trying to circle one another--that is if they are going in opposite directions, they're paths would curve into one another. Or would they...Now I have a math question that is bugging me because of this stupid question.

You may be confusing moths with black holes.  freshofftheufoΓΛĿЌ  04:50, 13 June 2006 (UTC)

Say you have two moths flying toward each other carrying a light source. They are attracted to light 10 meters away, and their paralell paths are seperated by 5 m, would they crash into each other? I suspect this would depend on their initial velocities....Sounds like this would make a good text book calculus question. Anyone have an answer? XM 12:21, 12 June 2006 (UTC)

Have you ever seen a moth fly? That's not calculus, that's turbulence. Black Carrot 21:40, 12 June 2006 (UTC)

Web

Can there be non www websites (those that dont start with www.)--are there any? And can there be anything for the suffix part of the address--instead of/ .com .org .net .edu .uk etc.... Mayor Westfall 04:43, 12 June 2006 (UTC)

To answer the first question: yes. You're on one. wikipedia doesn't require a www, and usually uses a language code. There is no restriction about this part of the URL. One website uses xxx instead of www, the physics arxiv. As for the second question, see top level domain for a list of what the final parts can be. -lethe ^{talk +} 04:55, 12 June 2006 (UTC)

For the first part (the www and things that replace it), see subdomain (and you can have sub-subdomains and such). Within the domain name, things go from largest on the right to smallest on the left. --AySz88\^-^ 06:21, 12 June 2006 (UTC)

There was a crazy Math teacher in my college whose website was wwww. ... .br people always wondered what that could mean. Everyone knew he was a Nazi (really) so people usually associated that, like White World Wide Web and stuff like that. VdSV9•♫ 11:48, 13 June 2006 (UTC)

Birds' sexual organs

When two birds mate/have sex/whatever, what part of the bird's anatomy is stimulated in order for it to have an orgasm? As far as I know, most birds have no obvious external sexual organs (I know that a few species of birds do have a penis but for the sake of argument, I'm talking about the majority that don't). As anyone that's ever owned a male budgerigar can tell you, birds (or at least budgies) do have orgasms and will dry-hump just about anything in order to get themselves off - I'm not 100% sure about hen birds but I presume they get something out of it too, otherwise there'd be no incentive to mate. Basically, what part of the bird's anatomy is analogous to the penis or clitoris? —The preceding unsigned comment was added by 81.77.227.52 (talk • contribs) 22:09, June 11, 2006 (UTC)

• Our article on birds probably mentions cloacas. There's enough animals that don't get any pleasure out of sex. In those cases they're simply acting on their instinct to survive and produce offspring. - Mgm|^(talk) 08:58, 12 June 2006 (UTC)

learning how to fix mobile phones

Hello All,Good Day.

I am hoping to learn the skill of fixing mobile phones. Which is both for hardware and software. I have access to buying all the necessary machines for doing this job, but I have no idea, how do I go about starting it, and how mobile phones work, and how to check, which part of the phone is not working, thus thereafter be able to fix it.

I did few searches on wiki, but nothing concrete showed up to guide me, so any help on how can I find such topics on wikipedia or any help on directing me to where I can find such specific help, will be highly appreciated.

Best regards,

Ken.

• I'm sorry to say this, but if you have no ideas about the inner workings of a mobile phone, starting such a business on your own is probably a bad move. Try learning with a existing company first. (Also mobile phones differ in design between brands). HowStuffWorks.com should have a nice article on the subject of how phones work. - Mgm|^(talk) 08:55, 12 June 2006 (UTC)

This would not be a good medium-term business. Phones are gravitating towards the 'unfixable', like a memory chip or processor. Either phones become a single chip you put in your ear, or they keep the same format and become computers. --Zeizmic 11:43, 12 June 2006 (UTC)

• • Your right there is little fixing possible at the PCB level with a board that fine but there are still many other things that can go wrong with a phone like gunk in the keypad and on contacts between various parts that can be fixed with simple dismantling cleaning and reassemblly, i have a feeling that this is a large part of what phone repair shops spend thier time doing. As for single chip in your ear unless voice recognition improves hugely i can't see people accepting it. Plugwash 11:55, 12 June 2006 (UTC)

Civilization of birds

Suppose that humans became totally extinct, leaving the planet intact (i.e. no nuclear war, asteroid strike or anything like that) and that birds eventually evolved, over several million years, to fill the niche left behind. Which species of bird do you think would be the one to step up and assume the role of 'masters of the planet'? Parrots? Crows (these seem to be the most intelligent birds)? Anyone have any theories? --81.77.227.52 06:33, 12 June 2006 (UTC)

I don't think it would be a matter of intelligence as much as of being omnivorous. As far as I know, crows eat pretty much anything and so do seagulls. –Mysid^(t) 07:10, 12 June 2006 (UTC)

Seagulls are tough and adaptable but the parrot species have a complex social structure and have already evolved the opposable 'thumb' (toe, in this case). Surely the ability to manipulate objects with more than a beak alone would be an advantage? --81.77.227.52 07:15, 12 June 2006 (UTC)

Depends what you mean by "niche". The first bird to move into an empty house is always the pigeon, but they wouldn't be able to drive the buses. I would have thought mammals would be more likely to take over most of the opportunities. Some countries already have more sheep, cattle, or pigs than humans, so presumably the land would be left to them.--Shantavira 07:50, 12 June 2006 (UTC)

Cattle and other domestic animals have, however, been overbred to produce as much milk or meat as possible, so that they are unable to move or react as fast as required "in the wild". Many of them would be unable to survive without humans. –Mysid^(t) 07:59, 12 June 2006 (UTC)

Who said that humans are the masters of the planet now? Us humans? Why aren't ants the masters? or beetles? or bacteria? ;-) —Bkell (talk) 08:48, 12 June 2006 (UTC)

Because bacteria have not formed cooperations that produce anti-humanic drugs, and ants & beatles don't spray chemicals on human cities to remove them from their habitat. XM 13:11, 12 June 2006 (UTC)

If you want to be anal about it, ants do spray chemicals to remove just about anything edible from the environment. They are just more ecofriendly than humans. Humans kill the ants and let them rot. Ants make a chemical trail to a food source (could be a human) and rip it apart into little bite-size chunks. However, I do not like this question. Why should birds take over? Why should it be a land animal? Why not the dolphins? A proper question would be: If humans were gone, would there be an animal that would spread across the entire world, pushing out other animals and plants? --Kainaw ^(talk) 13:30, 12 June 2006 (UTC)

I think it wouldn't be any kind of bird. It would be some kind of mollusc or insect, or crocodile. Dolphins would still be the most intelliegnt species (if they'd still be here) but of course they won't be the 'masters' but just continue to play joyfully as ever. – b_jonas 09:06, 12 June 2006 (UTC)

Seems like chimps would step it up, as they are closest to us XM 13:13, 12 June 2006 (UTC)

To replace humans something would need the ability to use tools, and need hands and opposable digits, so monkeys seem the only likely successor, possibly through evolution, leading to another humanoid race. Philc _T^E_C^I 19:37, 12 June 2006 (UTC)

But one that would look as different from chimps as we do (more or less, most likely). However, whoever "rules the world" after us might not be a "civilization," as the header implies. Dinosaurs, for example, were the top predators for a long time, but had limited mental capacity. I can imagine the descendents of eagles, say, coming "on top" without building a civilization. zafiroblue05 | Talk 00:57, 13 June 2006 (UTC)

leaving aside the impossibility of assuming that any species of sub-species will achieve evolutionary success in the environment of the unknowable future I'd go with the 2 birds that can already be considered as tool users. That is the Raven which has been known to drop pebbles into water to raise the water level so it can drink; and the Indian Black kite which picks up burning branches & drops them somewhere a fire can start inorder to scare out prey. AllanHainey 11:29, 13 June 2006 (UTC)

Nah, you're all wrong. It'd be the rats. Skittle 12:58, 13 June 2006 (UTC)

Whenever it comes to defining a creature that rules the world, why is aquatic life always completely ignored, despite water covering 70% of the surface of the earth. Philc _T^E_C^I 15:25, 13 June 2006 (UTC)

I think the reason is based on moving under water. Even the smartest water creatures must have a fin to move around. If they don't have fins, they'll grow them, like whales (or, to be precise, they'll evolve to have them). The necessity for fins more or less precludes the development of anything like opposable thumbs, so they'll never really develop an extensive use of tools, and therefore will never have civilizations. zafiroblue05 | Talk 21:39, 13 June 2006 (UTC)

...or discover fire for that matter. They also smell of fish. ;P --Kurt Shaped Box 21:59, 13 June 2006 (UTC)

Yeh but dinosaurs didn't exactly lay down the foundations of modern civilisation, and they're still considered to have ruled the world, if you ask me the aquatic life at the time of the dinosaurs ruled much more of the world than the dinosaurs. Philc _T^E_C^I 23:19, 14 June 2006 (UTC)

dna

What's the difference between - INVERTED REPEAT & PALINDROMIC SEQUENCE ? — Preceding unsigned comment added by 59.93.201.69 (talk • contribs)

An inverted repeat is called a palindrome when no nucleotides intervene between the repeats. –Mysid^(t) 07:09, 12 June 2006 (UTC)

For example,

GTACCAG-GCAAATC-GACCATG

is an (or has an) inverted repeat, while

GTACCAGGACCATG

is a palindrome (that is also an inverted repeat). zafiroblue05 | Talk 01:04, 13 June 2006 (UTC)

difference b/w velocity and acceleration?

what is the difference b/w velocity and acceleration?...please illustrate me with simple example. thanks — Preceding unsigned comment added by 80.247.152.121 (talk • contribs)

Velocity describes how fast an object moves (its speed) – acceleration describes the rate of change of its velocity. –Mysid^(t) 07:05, 12 June 2006 (UTC)

actually i m having problem understanding the term "rate of change of velocity"...can u kindly explain it please???

It is how fast the speed changes. Let's say you're driving a sports car at 80 mph, and just for the fun of it accelerate to 90 mph. Let's also assume that it took, for example, 5 seconds to do that. Now your velocity has changed 10 mph in 5 seconds—this is the rate of change of your velocity. If the acceleration of same amount takes longer, the rate of change is smaller. The acceleration can be calculated by dividing the change of velocity by the time it takes; a = 10 mph / 5 s ≈ 2.93 ft/s². –Mysid^(t) 08:10, 12 June 2006 (UTC)

You're driving along the road at a steady 60 kph (or 16.66 meters/second). Then you speed up for 20 seconds until you reach 70 kph, then maintain that speed. In those 20 seconds, your velocity (= speed) increased from 60 to 70, an increase of 10 kph. 10 kph over a period of 20 seconds works out to be an acceleration of 13.9 centimeters per second per second. JackofOz 08:15, 12 June 2006 (UTC)

As another example, if you're driving at a constant 100 km/h, then your velocity is 100 km/h, but your acceleration is zero, because your velocity isn't changing. If you decide to speed up, then as you speed up your acceleration will be positive and your velocity will increase; if you decide to slow down, then as you slow down your acceleration will be negative and your velocity will decrease. (As you slow down, your velocity will remain positive, as long as you're still moving forward, even though your acceleration is negative.) —Bkell (talk) 08:44, 12 June 2006 (UTC)

A change in direction is also a change in velocity, hence travelling at a constant speed in a cricle also has acceleration. Philc _T^E_C^I 19:35, 12 June 2006 (UTC)

As a further example, you're driving along in your car at 200 km/h (55.5 meters per second), and you hit a brick wall, coming to a stop in ten milliseconds. Your acceleration is (55.5 m/s) / (0.01 s) = 5,550 meters per second per second, or about 555 times the force of gravity. Ouch. --Serie 22:06, 12 June 2006 (UTC)

Which neatly illustrates the fundamental difference. Velocity is a measure of one effect of a force, whereas acceleration is a measure of force itself. JackofOz 23:51, 12 June 2006 (UTC)

Body Volume

Can you please supply me with the average VOLUME of the human body? This can be answered in cubic inches or cubic centimeters, preferably the former. Many Thanks Dr. Robbie Brown.

Ask A Scientist discussed the same – it can be found out by dividing the average human mass by 0.001 kg/cm³. According to human weight, an average US male weighs about 80 kg, so the average volume of an US male would be 80,000 cm³. –Mysid^(t) 07:36, 12 June 2006 (UTC)

• You could find out your own volume for yourself (although it's a bit messy). Fill a paddling pool to the rim with water and carefully step in and subnmerge yourself entirely. When you're done, step out and measure the amount of water still in the pool. The amount of water that spilled over when you went under is your volume. I don't recommend using your bath tub for this. After you get that amount of liters or gallons, cubic centimeters or inches are only a calculation away. - Mgm|^(talk) 08:51, 12 June 2006 (UTC)

Eureka! --Ginkgo100 ^{talk · contribs} 19:10, 12 June 2006 (UTC)

Just weigh yourself. For a first approximation, your density is about the same as water: about one gram per cubic centimetre. (You can shift that by five percent or so depending on whether or not your lungs are full of air, and whether you count that as part of your volume.) Note, for your convenience, that Google can do unit conversions for you—follow the link for an example: 1 cm^3 in cubic inches. TenOfAllTrades(talk) 16:44, 12 June 2006 (UTC)

The calculs are plain. Man floats a little (nose, chin and toes), so his density is not very different from water's, this is what Ask a Scientist's constant says. 1 kg of water defines a volume of 1 liter or 1 dm3. So man's volume is its weight in dm3, 1000 x his weight in cm3. For in^3, try Gogle and search, eg, "80000 cubic cm in cubic inches" which gives 4882. --DLL 16:44, 12 June 2006 (UTC)

A better approximation would be 1 kg body weight = 0.9L = 900ml. Non-average fat and muscle percentages change this. For a 70kg person, then 63L --Seejyb 22:44, 12 June 2006 (UTC)

additives

which kind of organic nitrates are added to diesel?

Cyclic nitrates are usually used as a diesel fuel additive.They reduce the autogenous ignition temperature of diesel fuel more than aliphatic nitrates; bicyclic nitrates are more effective than monocyclic nitrates, ex- cyclohexyl nitrate . Also, the organic nitrates proved to be the most suitable as components of starting fuels for diesel engines. (Ref: Springerlink)

pop and pop3

i've encounterd within my mobile a computer term pop3 server wat is this??? and what is pop??....also there are two other terms WAP and secure WAP Network...please inform me about these!...thanks

Try the articles Post Office Protocol and Wireless Application Protocol. —Zero Gravitas 07:51, 12 June 2006 (UTC)

(after edit conflict) Briefly, POP stands for Post Office Protocol, a communications protocol used in email services, and 3 is its current version. A POP3 server is an email server where your emails arrive and where you can download them to your mobile phone. WAP stands for Wireless Application Protocol, and it can be used e.g. to access Internet from the mobile phone. –Mysid^(t) 07:54, 12 June 2006 (UTC)

mobile phone as modem!

i've a smartphone "i-mate sp3i"...and i want it to serve as modem for my PC. i tried to search for it on i-mate's official website but couldn't find any material...

actually i use gprs on my phone n browse websites but i want to browse these websites on my pc through mobile.i ensure you that my mobile has this option to act as modem for my PC..but i m unable to find that option..please help me????

IP address configuration

Hi, I need to configure my laptop as the DHCP client in the office but assign a static IP at home, for the broadband connection. As of now, I do this change manually every day. Is there a utility which will allow me to reconfigure these settings on the fly ? -- Wikicheng 09:04, 12 June 2006 (UTC) '

• Additional information please; What operating system are you using? -Benbread 10:57, 12 June 2006 (UTC)

It is Windows 2000 professional. -- Wikicheng 12:04, 12 June 2006 (UTC)

The manual way to change it would be to look into the properties of the network interface, then look at the properties of "TCP/IP settings" and changing it there. But there must be an API for easily changing these settings. I know it. -- Daverocks (talk) 13:50, 12 June 2006 (UTC)

I haven't tried it myself, but a bit of googling (the first hit for windows dhcp static bat if you must know) finds this. Create .bat files with those one-liner commands, make shortcuts for both to the desktop and Bob's your uncle (knock on wood). ^{(notmyfaultifyoufryyourcomputer.)} Weregerbil 19:22, 12 June 2006 (UTC)

PERFECT !!! It works!. Just what I was looking for. Thanks a lot. -- Wikicheng 04:06, 13 June 2006 (UTC)

Several Science Experiment Questions

For a home science assignment I am doing an experiment on the effects of age on cognitive ability and memory. How I am doing this is getting some cards with 10 numbers, 10 letters and 10 mathematical questions on it. I get the subject to remember the numbers and letters for a set amount of time and after 5, 10 etc minutes I ask them to recall. I then record their success rate. I then ask them to complete the mathematical problems which I time. These two values I compare to other people from different ages etc.

In this type of experiment, what is the control? would it be the average of all scores?

Any improvements I could make to it?

Also, the assignment calls for a "background" section to be written as well as the Aim, Method, Results, Conclusion etc. In a formal experiment, what is the "background"?

Thanks Wayne

You would not really have a "control", I don't think, although if you need one I suppose the average value of each age group would do (although this is certainly not a control in the strict sense). You could mention things like the standard deviation at each age group (which, I would imagine, would vary considerably as you get to the youngest and oldest members of the experiment). Your test sounds fine, but it does sound a little easy. I would imagine that most people can remember 10 letters in a row in 10 minutes. Maybe you could try lowering the time a little, to increase the spread of results? Batmanand | Talk 11:26, 12 June 2006 (UTC)

They're not asking them to look at them for 10 minutes but to recall them after 10 minutes has passed. So increasing the time would make it harder, not lowering the time. Skittle 12:50, 12 June 2006 (UTC)

They get the numbers and letters to remember and they only get to memorize it for 2/3 minutes. Then I test them after 5, 10 minutes and mabye 20 or 30 minutes. Wayne

Most studies on age and memory have to do with transfer of short-term memory to long-term memory. That takes at least 20 minutes until an event is completely removed from short-term memory and in long-term memory. So, you should work on testing both. After 5 or 10 minutes, you are certain that the events (the cards) are in short-term memory and not long-term memory. 20-30 minutes later, it is in long-term memory. Obviously, mistakes they make in short-term memory will continue into long-term memory (unless they make a lucky guess). Your hypothesis can be that older people have a greater loss in transfer from short to long-term than younger people. You can even expand to include children. Are children better or worse than young adults? --Kainaw ^(talk) 13:23, 12 June 2006 (UTC)

I'm not sure that claim is completely accurate. The popular phrases "short-term memory" and "long-term memory" don't map directly onto the brain. When a subject is given a stimulus (e.g. a number on a card in this case) they will usually rehearse it by mentally repeating it. At this stage it is in working memory (or the phonological loop in Baddeley's terms). As long as the subject continues to rehearse it, for whatever amount of time, it will continue to be in working memory. It is for this reason that memory experiments often include a distractor task (e.g. simple arithmetic) between item presentation and test of memory retrieval. At the same time, the subject will be primed such that the stimulus will be more likely to be remembered given a cue or presentation of part of the stimulus (e.g. if the stimulus is a 9 digit number, given the first 5 digits). This is also a form of "short-term memory". Further, the details of the episode in which the stimulus was presented, as well as the stimulus itself, will be stored in the subject's hippocampus (part of "long-term memory") and will also leave a trace in other medial temporal lobe structures ("intermediate-term memory"). After a period of days, the content of the particular episode will slowly be consolidated into various association cortices (also considered "long-term memory"). The summary of the story is that a large number of different brain regions are all taking in the same stimulus and handling it in different ways, which do not all easily map onto a simple short/long-term distinction. Whew! That's a fair, quick summary... 128.197.81.181 18:28, 12 June 2006 (UTC)

I defentantly like the idea of testing the performance of the short term versus the long term memory of different people. I have changed it so they will be tested after 5/10 minutes and 30/40 minutes, however I will not restest the maths problems as that is not a memory test. I was also thinking of noting if a subject says that he or she says that they "cannot remember" or he or she gives incorrect results as I may be able to draw some (dunno what though) conclusions from this. - Wayne

I belive that the best way to compare the results would be by using a t-test. You can read about the t-test here, and there's a pretty simple on-line calculator here. You don't need a control group, by the way, since you yourself are not manipulating any variable. Rather you are comparing two populations to see if there is a significant difference between them. — Asbestos | Talk (RFC) 14:58, 12 June 2006 (UTC)

To answer the other part of your question: "Background" would be a description of what people generally write about memory, and how it changes with age. How long have people known it to happen? When do they say it should happen? Why does it happen? Quote a biology or physiology book. It would also include the difficulties that the changes you are measuring may be causing people, or the practical importance of the effect.. Background gives the reader a perspective on what you are testing, and why. --Seejyb 22:12, 12 June 2006 (UTC)

phd or research in Bioinformatics

I complited my M.Sc Bioinformatics from Tamilnadu and would like to do Phd or research in Bioinformatics from Bangalore or from Tamilnadu. I want to know which all universities are providing the Phd or research cources and how to apply for the same. What all qualities and qualification is needed?

Contact the universities in the geographical area where you would like to study and ask about their programs. --Ginkgo100 ^{talk · contribs} 19:13, 12 June 2006 (UTC)

Duchenne's muscular dystrophy

Concerned about the possibility of Duchenne's Muscular Dystrophy (MD) to future children by using the pedigree diagram and all other possibilities.

Scenario:

There is no evidence of MD on the husband's side of the family. The husband, the brother and the parents are normal.

The wife does not suffer from MD, and neither do her parents, but she has a brother who died from MD at the age of 7.

The couple have no children, but are anxious to start a family.

Please could anybody helps me with this.

Screen the mother for the mutation using haplotyping. If the mother is a carrier then there is a 50% chance of boys being affected and girls being carriers. Prenatal screening will allow potential fetuses to be tested for the mutation and aborted accordingly. --Username132 (talk) 14:35, 12 June 2006 (UTC)

See a genetic counselor to discuss the possibility. Rmhermen 14:59, 12 June 2006 (UTC)

Yep. Genetic counselor should be the one to help with all your information and decision-making needs. There are various associations in the UK, the USA (although this site looks more sentimental) and Australia, among others, that you may find helpful. There are associations in Canada and New Zealand and other countries too. They should be able to give you information and/or direct you to a specialist genetic counselor. Good luck with whatever decision you make. Skittle 16:17, 12 June 2006 (UTC)

Balancing a chemical reaction =

Hello, I need to find the product of this reaction and balance it.

(I used _ to denote a subscript. H_2 = H(subscript)2 )

H_2CrO_4 + AgNO_3 → _____

This is a homework problem, but I would just like a little help, could someone point me in the right direction? I do not have a problem balancing these, but every problem like this in my textbook already has the product written and I cannot find how to actually find the product of these type of reactions if it is not given. Dont I need to know the charge of those compounds? I guess the problem is, I can find the product of reactions composed of individual atoms, or cations/anions that I know the charge of (like Nitrate, Phosphate etc.. which are in my book), but I do not know the charge of the compounds in this reacion. And would AgNO_3 be called Silver Nitrate?

Also, if anyone has any helpful tips about these types of problems, please share.

Any help would be much appreciated!

--207.4.165.39 14:29, 12 June 2006 (UTC)

Where no charge is indicated, the charge is assumed to be zero (neutral). So H₂CrO₄ (chromic acid) has an overall charge of zero, as does silver nitrate.

The type of reaction here is called a double displacement reaction (also called a 'double replacement' reaction). When you dissolve those compounds in water, they break up into their component ions, and then figure out which anions can be paired off with which cations. You have to look for ions (anions/cations) that you recognize; you've probably got a list of common ones that you'll need to know. Hopefully that will get you started on your homework. TenOfAllTrades(talk) 14:51, 12 June 2006 (UTC)

I think the simplest thing to say is that you need to learn the charges of more ions. For this example, you have 2 H's in the first compound so you can figure out the charge on CrO_4 from that. For the second compound you should learn the NO_3 ion's charge (Ag also has a most common charge that is helpful to learn.) Rmhermen 14:55, 12 June 2006 (UTC)

More to the point, once you remember that HNO₃ is neutral, figuring out the charge of the NO₃ ion is easy. Of course, it's harder with polyprotic acids, such as H₂CO₃ or H₂SO₄ since those may lose a variable number of hydrogens to give ions with different charges. —Ilmari Karonen (talk) 16:03, 12 June 2006 (UTC)

• But if H₂CO₃ or H₂SO₄ lose all their hydrogen ions, the charge of the remainder ions is still simple to figure out. - Mgm|^(talk) 08:11, 13 June 2006 (UTC)

Using a second screen just to show a screensaver

Large "digital frames" that you can hang on your wall to display your digital pictures are much more expensive than regular lcd computer monitors. Is there any way, using windows, that I could attach a second screen to my computer, hang it on the wall, and set it to show my photo-viewing screensaver? Any thoughts or advice? — Asbestos | Talk (RFC) 16:58, 12 June 2006 (UTC)

That's feasible, but may be tricky to achieve. Another idea is to get a LCD TV, and use your digital camera. Most of them come with a form of video output, and support slideshows. This would involve the least amount of wiring and fuss with your PC. Also, LCD TVs are generally cheaper than LCD computer screens.

A second monitor is not difficult. You just need two video-outs. Dual-head cards make it very easy. As for the program, there are photo-viewing programs (doesn't Windows XP come with one built-in?). If you really like the screensaver version, you can run screensavers as programs. You don't have to lockup the computer. The problem you will have is that the mouse will tend to get lost when you accidentally drag to the second monitor. --Kainaw ^(talk) 17:45, 12 June 2006 (UTC)

Ok. Would there be any way to lock my mouse into my primary monitor when I'm not changing anything in the second monitor? — Asbestos | Talk (RFC) 17:55, 12 June 2006 (UTC)

Not that I know of. It would, of course, depend on the video driver. All of the popular ones that I've used allow the mouse (and windows) to slide back and forth freely between the monitors. --Kainaw ^(talk) 18:00, 12 June 2006 (UTC)

There exist mouse utilities that allow you to set boundries for the pointer. I could never reason why they would want to do that but it seems it would be useful in a situation like this.  freshofftheufoΓΛĿЌ  02:23, 13 June 2006 (UTC)

I've never used this program but it seems to be a pretty universally respected piece of code: Ultraman has a setting to Lock mouse to active window or primary monitor.  freshofftheufoΓΛĿЌ  02:34, 13 June 2006 (UTC)

Thanks! 65.96.107.116 12:34, 13 June 2006 (UTC)

training as bodybuilder

what role does taking or knowing about atp plays in my quest as a natural body builder

Are you referring to adenosine triphosphate? --Kainaw ^(talk) 18:02, 12 June 2006 (UTC)

I've never heard of anyone taking ATP as a supplement, if that's what you're asking. Your body makes more than enough ATP for its own purposes (the article in fact states "1 kilogram of ATP is created, processed and then recycled in the body."). As for knowing about ATP? I can't really see how knowing about ATP will affect your body building much — do you need to know how the CPU works to be able to use a computer? — but learning about ATP will probably play a part in your quest to understand high-school biology. — Asbestos | Talk (RFC) 18:21, 12 June 2006 (UTC)

Yuck. I take back what I said above: it looks like there are a lot of people selling "ATP supplements" over the web, some even claiming that all but the puniest of "weekend warriors" really need their products to prevent strokes and what-not. In my view this is BS and they are selling snake-oil. The only piece of supporting evidence I could find skimming through Google Scholar was an article saying that it may help prevent brain damage after trumatic head injuries in rats. Unless you plan on getting hit in the head a lot, and are a rat, I personally don't see the point. — Asbestos | Talk (RFC) 18:31, 12 June 2006 (UTC)

It might make you more energetic. Yanwen 19:10, 12 June 2006 (UTC)

How? ATP is a cell's "energy currency," but all the ADP/ATP a cell needs is already present. The body is designed to derive its energy ultimately from carbohydrates, fats, and proteins, and it is stored in those forms as well. --Ginkgo100 ^{talk · contribs} 19:17, 12 June 2006 (UTC)

Genetics

Actually I'm brunet with a bit dark skin. If I marry a tall blue-eyed blonde, what is the probability of the nordic type person birth (any gender)? I read it's small because my type is in fact a dominant gene. And how many generations should pass (counting my offspring as first) to achieve the nordic type? Thanks :) --Brand спойт 21:00, 12 June 2006 (UTC)

Hair_colour#Genetics, Eye_color#Genetics, and Skin_color#Genetic_determinants should help. Whether your kids display recessive characteristics, like blue eyes, depends on whether you're a carrier for that characteristic or not. Does anyone in your family have blue eyes? The "how many generations" question depends on who your children decide to breed with, and could only be answered with an estimate of probability. Black Carrot 21:33, 12 June 2006 (UTC)

No, nobody is blue-eyed in my family. What if I assume that my children will breed with the same-type partner? --Brand спойт 21:48, 12 June 2006 (UTC)

Assuming the trait is passed on through the simple dominant/recessive-type gene, a Punnett square will help you work out the probabilities from any breeding system you care to describe. I don't know how to work out anything more complicated than that. Black Carrot 22:20, 12 June 2006 (UTC)

Neither eye color nor hair color are single-gene traits, nor is being a "nordic type person". And all of the various genes so far identified as being involved are assorted independently. There's no way to make any reasonable prediction here. If you want to play around with what's understood, search Online Mendelian Inheritance in Man (OMIM) for "hair color" or "eye color". It will give you some appreciation of how much more complicated the transmission of these supposedly simply traits is than most people seem to believe. - Nunh-huh 22:45, 12 June 2006 (UTC)

Black is beautiful. Don't let the Nazis win. :D -- Миборовский 23:13, 12 June 2006 (UTC)

If you have double dominant genes, which is likely if you have absoultely no family history of these traits, all of you children will inherit the dominant traits, and none have the recessive traits. Philc _T^E_C^I 00:04, 13 June 2006 (UTC)

Wrong. These are not traits transmitted at a single gene locus. It makes no sense to discuss them in terms of dominant vs recessive when the actual specific genetics have not been characterized. - Nunh-huh 00:34, 13 June 2006 (UTC)

Nunh-huh is correct, we simply do not know enough about the genetics of hair, skin and eye colour to accurately predict such things. The genes we do know of can give you some pointers, but unless you sequence your alleles, its very difficult to even speculate about these. Some recessive MC1R alleles predispose to fair skin, red/auburn/strawberry blonde hair and freckles. And SLC24A5 variation appears to corrolate with skin colour. There are also some recessive subclinical alleles of albinism genes (eg. Tyrosinase, Dopachrome Tautomerase and Tyrosinase related protein) that result in very pale skin and white/blonde hair. Oddly enough, the genetics behind Californian blondes (i.e. blonde hair, tanned skin) is currently unknown. It appears that it might have something to do with the structure of eumelanin biopolymers and is possibly dominant over red hair alleles.

So while it is not possible to accurately predict in any scientific way, what we do know would suggest the odds are against you producing "very Nordic" progeny. Since the paler phenotypes are often recessive (due to a loss of function in genes involved in melanogenesis) unless you are carrying recessive "Nordic genes" (which also appears unlikely), its probable your children will get an assortment of darker and lighter skin/hair genes. Exactly what that assortment means in terms of their manifest hair, skin and eye colour, well, thats anyone's guess. But its more likely to be something in between than at either extreme. Rockpocket 01:49, 13 June 2006 (UTC)

Actually, I believe that mixed-race babies tend to have fair hair and colorful eyes. So you can get your little halfbreed Aryan. But just for a few years. -- Миборовский 02:09, 13 June 2006 (UTC)

Charming. Genetic counseling from someone who finds "mixed-race babies", "half-breed", and "Aryan" to be useful categories. And is apparently unashamed! - Nunh-huh 04:44, 13 June 2006 (UTC)

I would have thought the ironic tone in Миборовский's post to be fairly obvious, but I guess not. — Asbestos | Talk (RFC) 15:46, 13 June 2006 (UTC)

Is it just me, or is this particular thread deeply disturbing? --Ginkgo100 ^{talk · contribs} 14:32, 13 June 2006 (UTC)

I'd say you're both deeply disturbing. *Cymbal crash* Black Carrot 22:37, 13 June 2006 (UTC)

The Genesis of Life- Crocodiles

Hello. My name is Natasha and I am really in a bind. I really need help finding information on the genesis of life for crocodiles. It is a school project, and tommorow is the absolute last day to work on it. I did need websites bacause that is what everyone is giving me. If you find anything on Spermatogenesis, Oogenesis, Female Ovulation, Fertiliation, Embryonic Development, Birth, and Genetic Variation, please just copy and paste and send it to me. Thank-you so much.

Troubled grade 9

You need to do your own homework. Nobody here will do it for you. Also, cutting and pasting is not what your teacher is looking for. (And not the point of your education.) The point is for you to learn something about the subject and demonstrate that to the teacher. I'd recommend that you actually read the articles on the topics you listed, and then write the paper based on what you have learned from them. Fortunately, you have a whole 2 days. --Booch 22:47, 12 June 2006 (UTC)

Hmm. Sorry about your bad planning! Our crocodile article doesn't help. Try searching google for "crocodile reproduction". There are some sites that you'll find that will be of use. [2], [3], etc. Similarly, "crocodile mating" and "crocodile fertilization" will all return useful results. - Nunh-huh 22:53, 12 June 2006 (UTC)

Doesn't a human fetus aged less than 2 months look like a crocodile's ? The we evolve and/or regress but they become perfect crocos for Mr and Ms Vuitton. --DLL 19:16, 13 June 2006 (UTC)

GMA 950

So the school I'm going to is reccomending that I get a Toshiba M400, they have some sort of special deal they're trying to negotiate.

The processors go anywhere from Intel Core Solo 1.6 to Intel Core Duo 2.16, not sure what they'll negotiate.

Memory will definately be 1 GB.

Gfx Card is unfortunately an Intel GMA 950 with 8 MB to 128 MB shared memory.

(12.1" screen = eww, Tablet = cool)

Now here's my question: Will I be essentially screwed as far as all gaming goes? I'm really hoping not, cause I was hoping for a laptop for the next few years that I wouldn't want to throw off a cliff. Also, anyone have this computer? How's it work

Looks like I'm going to be stuck playing the games on my desktop whenever I get a chance to get home. Oh well, less Hard Drive space hogs I suppose. Also, I wanted to get Oblivion but it looks like it'd run on my ATI Radeon 9600 better.

Maybe I should just badger my parents into getting a MBP 2.16 Ghz for me (Looks to me that unless the school gets a spectacular deal, the Toshibas will only be ~$500 less than the MBP, which has specs at about twice the Toshiba, especially graphics card). — Ilyanep (Talk) 22:53, 12 June 2006 (UTC)

It really depends what you mean by "gaming". Back when I played counter-strike, I considered a computer worthless if it couldn't run the game consistantly at 100fps+ without memory skips at 1024x768, or didn't have enough memory to smoothly concede minimizing the game client and loading third party programs.

Though CS is ancient, most current laptops still can't do that, but I'm guessing you won't be that hardcore for framerate. If you're into really pretty current FPSs or other depth-intense 3D games, then you'll probably be disappointed. I'm not sure how much better "sharing memory" methods are nowadays, but your vid card (and, of course, your screen) is really next to worthless as far as 3D gaming goes. On the other hand, RAM is sufficient and (if you get the 2ghz) there's probably loads of good games out there that you could run smoothly, as long as you manage your hard disk carefully to keep the cache file "cashing" smoothly.

Still, this computer is for school so you'd probably be better off using your laptop more productively... lets pretend the inadequacies are intended as a blessing to help you concentrate on your studies : ).  freshofftheufoΓΛĿЌ  02:15, 13 June 2006 (UTC)

Oh pshaw, I've got to live at this place :D.

Thanks for the help. Hopefully if the tablet isn't required we can go with a laptop at the same cost that has an ATI Mobility Radeon X1600. — Ilyanep (Talk) 02:51, 13 June 2006 (UTC)

They have begun issuing these to people I work with. What I don't get is, what's so special about the tablet feature? There is no way you can scribble half as fast or as accurately as you can type. I could see it making field work easier, since its a good way to navigate GUIs while being held in your hands. I don't see a single practical benefit to it for typical desk use, though. If you want to play Oblivion well, plan on spending a LOT for a laptop. And BTW, the reason no laptop can run CS at 100FPS is because no laptop has been made with a screen that refreshes that fast. Maybe because theres no perceivable benefit?

Agreed. But the MBP looks like it can run Oblivion at at least medium if not high settings. I think the Tablets are overpriced for a school setting. — Ilyanep (Talk) 16:55, 13 June 2006 (UTC)

Don't forget to factor in the cost of the windows XP license (wink) in the total cost of that system, since O won't run on OS X as far as i know. Also, put priority on the 256mb vid ram, and 2GB of sys ram, I play O a lot and it ran like crap without those.

Oh well, I'll probably uninstall XP on the computer I'm working on right now and put linux on it [to make it a file server] and then use this copy of XP on that one. Then I can keep Win and OS X backups on here and it'll basically be a free file server. — Ilyanep (Talk) 18:43, 13 June 2006 (UTC)

Odd Trait

What I was wondering was if talking during a T.V. show, or giving away the story is a recessive trait, because both my father's parents do so, thusly my dad and his sister also talk during shows. My mom doesn't and I don't, so would that make it recessive? schyler 23:56, 12 June 2006 (UTC)

I think that reasoning and manner of thinking and choice, are all factors and none could be attributed to a single gene. It is mostly choice really, unless they have OCD. Philc _T^E_C^I 00:00, 13 June 2006 (UTC)

That sounds more like evidence of nurture than nature. Black Carrot 02:03, 13 June 2006 (UTC)

Strong anecdotal evidence suggests that the need to control the remote control is inherited together with the Y-chromosome. - Nunh-huh 03:38, 13 June 2006 (UTC)

But even if that particular trait isn't inherited, that is how a recessive trait works, right? schyler 12:44, 13 June 2006 (UTC)

A recessive genetic trait is passed on through a gene sequence on one half of a chromosome. If it is combined with a "dominant" sequence on the other, its instructions are effectively ignored in favor of those of its dominant partner. (I'd appreciate correction if I got the wording wrong.) Point is, that trait isn't recessive any more than a brunette is a tabby. However, were it being caused by an interaction of dominant and recessive genes, yes, that's what it could look like. Black Carrot 17:45, 13 June 2006 (UTC)

Well, not one half of a chromosome, but one half of a chromosome pair, or one of a pair of chromosomes. And most geneticists would use "allele" rather than sequence. It's also not that recessive genes are ignored: they are usually transcribed and produce proteins, but the protein produced by the dominant allele has an effect that negates that of the recessive allele's protein. (For example, women who carry one allele for hemophilia (which is transcribed to produce a defective clotting factor VIII) and one allele for normal factor VIII produce both defective and normal proteins, and the normal protein is present in sufficient quantity that they do not usually experience clotting difficulties.) - Nunh-huh 22:17, 13 June 2006 (UTC)

A situation known as haplo-sufficiency (though that article could do with some work). When the normal protein cannot make up for the deficit in function from the other allele, it is known as a haploinsufficiency. Rockpocket 02:22, 15 June 2006 (UTC)

June 13

Guarani Indians from Asia

During a summer I spent in Paraguay, I saw a elementary school textbook that claimed that the Guaraní Indians (unlike other ethnic groups) originally came from South-east Asia (Malaysia, or around there), not over the Bering land bridge. The idea was something I'd never seen before, and what was most remarkable was that something that seemed at best rather pseudo-scientific to me was presented utterly as fact in government-sponsored textbooks. I'm wondering how an idea like that - which, after a little online and Wikipedia search, seems at best far-fringe, at worst entirely bogus - appeared in such a textbook. To be sure, a large part was some sort of national pride/chauvinism, as most Paraguayans have half-Guarani, half-European blood, still speak Guarani, and so on. (I should mention that many Paraguayans today look remarkably Asian, much more so than, say, North American Indians - perhaps partly because the "look," make-up wise, seems to be in style. But maybe only partly.) Still, there had to be some sort of (social?) scientific support for it, no matter how specious. But a little bit of research turns up little.

In short: is there any basis to a South-east Asian background of some South American ethnic groups? And how did such an idea make its way, untempered, into a government school textbook? zafiroblue05 | Talk 01:18, 13 June 2006 (UTC)

I don't know anything about the veracity of the claims you refer to, or their likielihood but there is certainly nothing unusual about government sponsored (even local government) textbooks making false or unverified claims, pushing a particular point of view, leaving out embarassing facts & even plain lying. The most well known example of this is Japanese history textbook controversies and their treatment of Japansese actions in the Manchurian and second world wars. I believe that Chinese textbooks are also somewhat lacking in unbiased historical fact too & U.S.A. educational authorities have also been criticised for misrepresenting history in Lies My Teacher Told Me by James W. Loewen. AllanHainey 11:53, 13 June 2006 (UTC)

There's the Kon-Tiki expedition of Thor Heyerdahl, but that went from South America to Polynesia, not the other way around. —Bkell (talk) 21:16, 13 June 2006 (UTC)

Polynesian peoples, who originated in South East Asia (probably Taiwan and surrounding area), probably visited South America. The main evidence for this is the kumara, a sweet potato originating in Peru which is used through the eastern half of the Pacific, and which is not considered likely to have reached that area without being carried by people. However, there is no evidence of any genetic legacy being left in South America by Polynesians. My source is The Quest for Origins by K R Howe, ISBN 0-14-301857-4.-gadfium 01:17, 14 June 2006 (UTC)

Half-life comprehension and computation...

This discussion has been moved to Talk:Half-life#Half-life_comprehension_and_computation.... Arbitrary username 19:48, 13 June 2006 (UTC)

Frontbend

Okay, I'm officially stumped. I don't get it. People are capable of truly astounding backbends. I have proof. I've seen it: [4] So why, why, is nobody capable of making an equal frontbend? I've asked contortionists, I've left questions here, and I've searched Google, and I can't find a single person who's ever seen it. What actual physical reason is there for this to be so impossible? Black Carrot 02:25, 13 June 2006 (UTC)

Maybe because the rib cage is in the way? In a backbend, the organs of the torso are stretched out, so they have to change shape, but not size. In a frontbend, there's nowhere for them to go. —Keenan Pepper 02:52, 13 June 2006 (UTC)

Or if explained another way, because the backbone isn't there.  freshofftheufoΓΛĿЌ  03:30, 13 June 2006 (UTC)

The joints of the spine permit greater movement towards the back than the front. It's not like there's a hinge in the middle of the spine that bends equally both ways; the joints of the spine are quite complex and permit a greater freedom of motion in some directions, and less in others. When you bend forward, the spinal bodies get closer together and block further movement in that direction rather quickly. When you bend backward, the spinal bodies get further apart, and so don't prevent movement. - Nunh-huh 03:37, 13 June 2006 (UTC)

I can see that shifting the organs would be a bit more difficult to the front, but would it really be that big a problem? Especially for skinny people like the one in that video.

I looked through our article on the spine, and I don't quite follow your argument. "Spinal bodies" seems to refer to the vertebrae themselves. You're saying a gap is produced between them when you lean back, but not when you lean forward? Black Carrot 17:38, 13 June 2006 (UTC)

Yes. (An illustration would be best for demonstrating this, and I really can't draw, so this is primitive and schematic). .

Even with my crude drawing, I think you can see that there's greater range of motion at the joint when bending backwards. - Nunh-huh 22:08, 13 June 2006 (UTC)

Wow, that's pretty awesome. Now, the backbends I've seen suggest that those gapes can become truly huge, without doing any damage. Why can't a similar gap form at the back? What's holding it together there that isn't holding it together in the front? Black Carrot 22:32, 13 June 2006 (UTC)

Ligaments, muscles, bony configuration, etc. That's why the "fulcrum" of the joint is at the back of the spinal body, not the front. - Nunh-huh 22:35, 13 June 2006 (UTC)

ELECTRONEGATIVITY

BY KNOWING THE ATOMIC NUMBER HOW CAN WE KNOW THE ELECTRONEGATIVITY ORDER OF THE ELEMENTS —The preceding unsigned comment was added by 202.88.227.171 (talk • contribs) .

The wikipedia page on electronegativity would be a good place to look to learn about the periodic trends and specific data values for this property. DMacks 06:57, 13 June 2006 (UTC)

Don't forget not to write all in capital letters (see above)- it makes it harder to read your post to some people! EvocativeIntrigue _{TALK | EMAIL} 10:47, 13 June 2006 (UTC)

Accidentally consuming electrons

What happens if a fully grown human eats a few million electrons? For example, if his food contains free electrons. What are the effects of electrons on a human stomach? 211.28.224.250 10:58, 13 June 2006 (UTC)

All matter that you normally see living on Earth is composed of mainly three things, electrons, protons, and neutrons. The food you eat has billions and billions and billions and billions... of electrons in it!! — The Mac Davis] ⌇☢ ญƛ. 11:25, 13 June 2006 (UTC)

"Free" electrons aren't present in food. Electrons in solution can only exist for nanoseconds before connecting with a molecule to form a negative ion. So whatever you eat, you'll only be eating negative ions and not electrons. On the other hand, if some food has a negative net charge, then as soon as you put it against your lips, the net negative charge will migrate to the outside of your body. Net negative charges cannot survive inside a conductive material like human flesh, and they move to the outside surface because of their self-repulsion. --Wjbeaty 07:58, 15 June 2006 (UTC)

I think he meant 'free electrons' (or may be negatively charged particles). Negatively charged bread, for example ? I don't think there will be any problem. The charges will get neutralised. If not, electron rich Faeces, may be ? -- Wikicheng 11:55, 13 June 2006 (UTC)

Metal has a lot of valence electrons - those are "free". I've seen shows where they use gold foil as a cake decoration and nobody appeared to get sick when they ate it. I don't what it feels like to poop gold foil though. --Kainaw ^(talk) 12:31, 13 June 2006 (UTC)

well, a couple hundred million extra electrons will do nothing, you probably "eat" this much all time in your mineral water. Electrons on a human stomach disperse to your skin.

The worst thing that could happen is that you would increse your electric potential and when you touched something electrically neutral there would be a small discharge with a shock. Much like when you walk dragging your feet on a large carpet. VdSV9•♫ 13:11, 13 June 2006 (UTC)

Look up Coulomb. A few million electrons is just nothing compared to it, and 1 coulomb is not very big.

yeah, what I meant on the "The worst that could happen" paragraph was in the case of a substantial amount of electrons, say... 10^16.

And one Coulomb is quite considerable. For instance, if the discharge time is one milisecond the current will be 1 kA. VdSV9•♫ 15:49, 13 June 2006 (UTC)

The human body can hold a considerable surplus of electrons with respect to the environment. I asked a related question here recently, and got an excellent answer: you might be interested to see the question, and the page that User:Heron pointed me to. --vibo56 ^talk 17:57, 13 June 2006 (UTC)

Redox reactions in steel manufacture.

Hi, I'm revising for my GCSE in Chemistry, and have seen mentioned in textbooks and on the specification that I have to know about the redox reactions involved in the Basic Oxygen Process of steel manufacture, when impurities are oxidised. Unfortunately I can't find much mention of them! Can anyone tell me simply what the redox reactions are for, say, silicon? I know it goes to SiO2, but I can't work out what the reduction and oxidation parts of the reaction are. Many thanks! --86.142.195.158 11:02, 13 June 2006 (UTC)

Basic oxygen steelmaking and Slag might be of a little use. Otherwise, the main impurities present in pig iron are: Carbon, Sulpur, Phosphorus, and Silicon.

The carbon is oxidised to carbon monoxide and carbon dioxide, and the oxygen is reduced.

The elemental sulphur reacts with the magnesium/aluminium powder to form Magnesium/aluminium sulphide. The sulphur is reduced and the metal is oxidised (remember, Oxidation Is Loss of electrons).

The phosphorus is first oxidised to $P_{4}O_{10}$ , Phosphorus pentoxide. This then reacts with the metal powder to form a Metal Phosphate via the reaction : $6Mg+3O_{2}+P_{4}O_{10}--->2Mg_{3}(PO_{4})_{2}$ (which you don't need to know for GCSE.)

The Silicon is, as you said, oxidised to $SiO_{2}$ and the oxygen reduced, but this can form acidic impurities in the steel, so it is reacted with CaO (from the decomposition of calcium carbonate) to form calcium silicates $CaSiO_{3}$, which are scraped off as slag.

Hope that helped --Eh-Steve 16:45, 13 June 2006 (UTC)

Thanks a lot! Much better than anything I could find. So would I be right in saying, for example, that the sulphur is removed like this (saying we use magnesium)?

$Mg--->Mg^{-}+2e^{-}$

$S+2e^{-}--->S^{2}-$

So the redox would be $Mg+S--->MgS$

One other question though please, how would you do the redox for the carbon and oxygen reactions? I'm not sure whether to write carbon as +4 or -4, or even if I'm allowed to do that as it bonds covelently?

Thanks a lot! --86.142.195.158 18:01, 13 June 2006 (UTC)

Your above equations are perfectly correct.

You're not technically "allowed" to use half equations for such covalent reactions as the oxidation of carbon, so you can approach it with a standard equation, or, if redox is absolutely required, by assigning the element with the highest electronegativity (i.e. oxygen), the negative oxidation state (i.e. $O^{2-}$).

I realise you're at GCSE level, so you don't need such detail. --Eh-Steve 19:21, 13 June 2006 (UTC)

Well, need to make that first half-reaction have Mg²⁺, not mono-anionic. DMacks 19:27, 13 June 2006 (UTC)

(edit conflict) What you've written above is roughly correct for the reduction of sulfur, except you meant to write $Mg^{2+}$ rather than $Mg^{-}$. As regards carbon, it's probably not helpful to express it as ions, but still in $CO_{2}$ the carbon is in oxidation state +4. I guess the point is that even though it's a covalent bond, it's somewhat polarized (that is, the shared electrons are at any time more likely to be found near the oxygen than near the carbon), so in some sense the oxygen still partially receives electrons from the carbon, which is why the oxidation state is notionally +4 (and likewise +2 in CO). But bond polarization is probably A-level stuff. Arbitrary username 19:34, 13 June 2006 (UTC)

Water Pressure

I have a 100 cubic metre water tank with a two inch pipe conected to the bottom of the tank. The pipe then drops 7.5m to a valve. My questions are:

1. Is it true that at the valve, 7.5m below the tank, I should have 0.75 bar of pressure?
2. If the pipe were to continue to drop to 10mts below the tank, and then return to 7.5mts (as in a siphon), would I still have 0.75 bar of pressure at the valve?
3. Does the length and/or diameter of the pipe influence the pressure?
4. Does the volume of water in the tank, or the shape of the tank i.e. (tall and narrow vrs. shallow and wide), have an influence on the pressure?

Sorry to ask so many questions.Groc 11:01, 13 June 2006 (UTC)

1. Only if the 7.5 m is measured from the surface of the water in the tank.
2. Assuming the above, yes.
3. No, as long as the valve is closed. Once the valve is opened, there will be a pressure drop that will depend on the size and shape of the pipe.
4. Only insofar as it affects the height difference between the valve and the water surface.

—Ilmari Karonen (talk) 12:04, 13 June 2006 (UTC)

What you need to know is the height of the water level in the tank. The pressure at the valve should be higher than the pressure at the top of the tank (which should be atmospheric ~ 1 bar), so it definately won't be 0.75 bar. The pressure at a given point, certainly as long as the water is fairly static (isn't moving) should depend only on its height and the pressure at the points where it is in contact with the air (ie, the surface at the top of the tank). You can calculate pressure differences by timesing height difference by density of substance by gravity. So the difference between the pressure at the top and the bottom of the pipe is 7.5m x 1 kg/L x 9.81 m/s2 giving an answer in pascals. Remember this is the increase in pressure as you go down the pipe. I assume you can convert pascals into bar. Skittle 12:11, 13 June 2006 (UTC)

It depends on whether we're measuring absolute pressure or gauge pressure; recall that the latter is the difference between the pressure in the pipe and the ambient pressure outside. Also note that we don't usually answer homework questions here. TenOfAllTrades(talk) 13:01, 13 June 2006 (UTC)

We don't answer homework questions that ask us to do the homework for them, but I feel it is different if it looks like they've tried to answer, then ask if their answer is correct and if they've understood the concepts. Skittle 14:37, 13 June 2006 (UTC)

And even if they're looking at gauge pressure, their answer is orders of magnitude wrong (assuming they don't have an extremely convenient height of water above the pipe), so I felt a little help would be ... helpful. I really hope they can converts pascals (unit) to bar (unit). Skittle 14:43, 13 June 2006 (UTC)

Assuming the 7.5m to be measured from the top of the water, and that they're interested in the gauge pressure, 0.75 bar looks correct to within a few percent to me — certainly not off by orders of magnitude. If you don't believe me, ask Google (using Pascal's law). The discrepancy in the second decimal is due to the original poster approximating g as 10 ms^-2. —Ilmari Karonen (talk) 22:30, 13 June 2006 (UTC)

D'oh! Rustiness means I took water's density as 1 kg/l rather than 1000kg/m3. I checked that so many times, because I don't like getting answers different to other people. :-| Skittle 09:09, 14 June 2006 (UTC)

To summarise: For a water column, open at the top, the pressure would increase by approximately 1 bar for every 10m difference between the surface of the water, and the "depth" of the point where you measure the pressure. This you learn when diving: 10m down you are under 2bar of pressure. The curves in the pipe between the surface and the measuring point do not affect the pressure at that point. The shape of the tank would change the distance between your pipe outlet and the top of the water, and therefore the total height of water, and therefore the pressure. If your measuring device is zeroed to atmospheric pressure, the reading at 7.5m would be 0.75, but if it were an absolute pressure that you are measuring, then the reading outside of the water would be 1bar, and at 7.5m it would be 1 + 0.75 = 1.75bar. --Seejyb 23:20, 13 June 2006 (UTC)

We have this in an article: Fluid statics#Hydrostatic pressure. moink 23:30, 13 June 2006 (UTC)

PE string for making fish net

What kind of "chemcial" or additives can be added in the process of manufacturing PE string so that the fish-net(for fish-farming) can be more durable, namely anti-aging and anti-corrosive.

Polyethylene is already fairly corrosion resistant and non-biodegradable, so what improvement is required exactly? I suppose you can use UHMWPE, and this is used in ropes (see Dyneema). IMO, nothing can be added to improve the rope durability unless the manufacturing method is altered, giving a different product. If mould resistance is required Triclosan can be added. Otherwise, not much. --Eh-Steve 17:34, 13 June 2006 (UTC)

keyboard shortcuts

Hi, I didn't know where else to look, and this is not a computer-science, so it wouldn't be on the math RD.

Well, I've been using MS word and this is annoying me. sometimes I need to switch to read other documents that are open in word, and to do that, I have to minimize or restore the document I'm writing to, then click on the one behind it to bring it forward. I want to work with my document maximized within the word window, and not have multiple word windows. So, Alt+Tab is not an option. For most programs, there is an alternative with Ctrl+Tab, and I often use it (I don't really like to rely much on the mouse to work, to maximize a window for instance, I always do: Alt, Spacebar, X), but it does not work in Word.

Finally, my question is: Does anybody know the friggin keyboard shortcut to alternate between multiple documents within an MSWord window? VdSV9•♫ 13:21, 13 June 2006 (UTC)

Oh, and the document I'm working on right now isn't showing up in the recently opened list. VdSV9•♫ 13:30, 13 June 2006 (UTC)

Ok, I figured out a way to do what I wanted. I closed both, then opened them again and they are number 1 and number 2 on the recently opened list, so I do Alt, A (in english it should be F to open the File menu), then 1 or 2 to go to the one I need.

But still it is not what I was looking for. So if anyone knows the answer to the question I would be grateful. VdSV9•♫ 13:37, 13 June 2006 (UTC)

What you are looking for is the keyboard combination CTRL-F6. This will sequentially bring to the front, one at a time, all the documents that are currently open.--Mark Bornfeld DDS 15:30, 13 June 2006 (UTC)

If you're on a Mac (probably not) press Apple + tilda. — The Mac Davis] ⌇☢ ญƛ. 07:50, 14 June 2006 (UTC)

Rare neurological disorder...

Hello....I am interested in finding out about a rare disorder called Reflexive Neurovascular Disorder. I have searched the web and your website as well and have found nothing. Could you help me out? Thank you.

Try Google, your library, and the American Medical Association's website. If you find enough info and are a registered user, please make an article about it. Emmett5 17:00, 13 June 2006 (UTC)

Could it be that you are looking for "Reflex Neurovascular Dystrophy"? That would be a pain syndrome. If so, synonyms include Complex Regional Pain Syndrome (the "most modern" term) and Reflex Sympathetic Dystrophy (commonly used) --Seejyb 19:26, 13 June 2006 (UTC)

Covalent bonds in HCl

Hi, I know that hydrogen chloride is bonded by a single covalent (sigma) bond, but does this involve an H 1s electron and a Cl 3p electron? This is what I was told at uni, but I was wondering why some sort of hybridisation (e.g. sp3) would not occur. (This would affect lone pairs and the exact nature of the sigma bond?) If this does not involve hybrid orbitals, what determines when this happens? Will this never happen for single-bonded diatomic molecules? Thanks. -postglock 15:04, 13 June 2006 (UTC)

The H-Cl bond is simply a sigma bond between a 1s orbital and a 3p_z orbital. Hybridisation as you were refering to it will happen in the same atom. A hydrogen's 1s orbital won't hybridise with a chlorine's 3p, as they are separate atoms. See Orbital hybridisation. But, that might not be what you're asking.

If you're asking whether or not the chlorine orbitals hybridise before the bond with hydrogen is formed:

There is no reason for hybridisation to occur as Cl has a ground state configuration of [Ar] 3s² 3p_x² 3p_y² 3p_z¹. This means that an sp3 cannot occur as the 3s can't be excited to give its electron to the 3pz, because that would form a single sp1 and 3 complete 3p orbitals. This means that the configuration:

$Cl^{*}\quad {\frac {\uparrow \downarrow }{3s}}\;{\frac {\uparrow \downarrow }{3p_{x}}}{\frac {\uparrow \downarrow }{3p_{y}}}{\frac {\uparrow \,}{3p_{z}}}$

goes to:

$Cl^{*}\quad {\frac {\uparrow \,}{sp^{1}}}\;{\frac {\uparrow \downarrow }{3p_{x}}}\;{\frac {\uparrow \downarrow }{3p_{y}}}{\frac {\uparrow \downarrow }{3p_{z}}}$

which seems to me to be completely silly. Anyone else's input would be nice though. --Eh-Steve 17:15, 13 June 2006 (UTC)

Thanks for the reply. The second half is exactly what I was trying to ask. Why wouldn't the chlorine atom's electrons hybridise before it bonds. I thought perhaps that chlorine should theoretically be able to form 4 sp3 orbitals, with three of them already filled with lone electron pairs. I am afraid I don't quite understand your explanation though, and the information at Orbital hybridisation doesn't quite tell me enough. I thought this kinds of (sp3) hybridisation should be able to occur in chlorine, even with its ground state configuration? It seemed analogous to the sp3 hybridisation of O in water, with two sp3 orbitals "pre-filled" with lone pairs.

$O^{*}\quad {\frac {\uparrow \downarrow }{2s}}\;{\frac {\uparrow \downarrow }{2p_{x}}}{\frac {\uparrow \,}{2p_{y}}}{\frac {\uparrow \,}{2p_{z}}}$

goes to:

$O^{*}\quad {\frac {\uparrow \downarrow }{sp^{3}}}\;{\frac {\uparrow \downarrow }{sp^{3}}}\;{\frac {\uparrow \,}{sp^{3}}}{\frac {\uparrow \,}{sp^{3}}}$

why wouldn't

$Cl^{*}\quad {\frac {\uparrow \downarrow }{3s}}\;{\frac {\uparrow \downarrow }{3p_{x}}}{\frac {\uparrow \downarrow }{3p_{y}}}{\frac {\uparrow \,}{3p_{z}}}$

go to:

$Cl^{*}\quad {\frac {\uparrow \downarrow }{sp^{3}}}\;{\frac {\uparrow \downarrow }{sp^{3}}}\;{\frac {\uparrow \downarrow }{sp^{3}}}{\frac {\uparrow \,}{sp^{3}}}$

If this is possible for Cl, then this would be possible for HCl, which then suggests that the lone pairs would be seperated to minimise repulsion ala the VSEPR theory? -postglock 18:15, 13 June 2006 (UTC)

In retrospect, when I look more carefully at the situation, there is no logical or quantum reason I can see why the above shouldn't happen, provided all sp3's are formed... In that case, the H-Cl bond is in fact a 1s to sp3 bond. Hmm... Your university teacher might have been oversimplifying. --Eh-Steve 19:08, 13 June 2006 (UTC)

Hmmm... I've just checked further in my textbook, and it appears to agree with my lecturer. It gives an example of a heteronuclear diatomic molecule (HF) and says that the H 1s orbital and the F 2p orbital are involved. Unfortunately, this section is on molecular orbitals, and seems to ignore why this would not hybridise... -postglock 03:16, 14 June 2006 (UTC)

One can rationalize why this could be true if one considers the shapes of the regions of electron density in s vs p atomic orbitals: s is spherical and closer to the nucleus, p is directional along an axis and further from the nucleus. Hybridizing some s into a p results in electron density closer and less directional than the p alone. If a covalent bond from atom A to atom B involves having electron density being directed towards B and displaced away from A, makes sense that this electron density would have a high p character on A. Remember that this is hand-waving, not proof: we use orbitals to explain observations; reality isn't a slave to our model:) DMacks 05:23, 14 June 2006 (UTC)

Interesting, but I always thought that although p orbitals were more "directional" than sp3 in terms of "pointiness," sp3 orbitals were more directional in terms of having more density on one side. What I mean is that p orbitals are symmetrical across a plane normal to the radial axis, and sp3 orbitals would be denser on the side of the bond. I suppose you are right, these theories only model reality; if it has been observed that HCl (for example) has lone pairs that are at right angles to the bond rather than tetrahedrally, then the model would hold. I guess what I would want to know then is if this lack of hybridisation would occur generally for all diatomic molecules... Thanks for the reply! -postglock 06:42, 14 June 2006 (UTC)

Hmm, I've read a bit further and I've also found similar inconsistencies with oxygen. It appears (from the lecture notes) that oxygen in O₂ will hybridise to form sp², but oxygen in the nitrate ion will form sigma bonds directly with its 2p orbital. I can't seem to figure out any general rule for these... -postglock 08:15, 14 June 2006 (UTC)

Briefly, the problem is that VSEPR is an approximation that works pretty well for figuring out the shapes of (many) molecules, but should only be applied with caution to trying to characterize what's 'really' going on. What happens in bonding is that new, so-called molecular orbitals are formed when bonding takes place. These aren't equivalent to the hybrid orbitals of VSEPR (though they're sometimes related), and they allow for more accurate predictions about where your electrons actually are. MO theory explains why the oxygen molecule (O₂), for example, is a diradical in the ground state—its electrons aren't all paired as you would normally expect. TenOfAllTrades(talk) 13:03, 14 June 2006 (UTC)

By first-principles, one has molecular hybridization among all orbitals that have compatible symmetry, and more hybridization among orbitals that are closer in energy. HF is actually used as the example of this approach in the Shriver/Atkins/Langford Inorganic Chemistry text:) This result by this method is that the F atom is sp hybridized, with the H—F bond and one lone pair occupying the two molecular orbitals corresponding to the F sp atomic orbitals and the other two lone pairs occupying the MO corresponding to the remaining F pAOs. "All we have to do" now is design an experiment to observe the electron density or test some predicted property that would distinguish the different cases... DMacks 14:53, 14 June 2006 (UTC)

Thanks for that advice. I suppose I'll just have to learn it all compound by compound. I just wish there was some general, simple rule :(. So, having read more about the diradical nature of oxygen, I am still a little confused – does O₂ involve sp² hybridisation or just 2p orbitals? Perhaps I just don't understand the nature of MO theory; is this a theory that is incompatible with the simplified orbital hybridisation theory? -postglock 13:42, 14 June 2006 (UTC)

I think you're getting bogged down in the hybridisation quagmire - though I know that university courses require people to understand it. Remember according to the theory s orbitals are spherically symmetrical and 4 filled p orbitals also produce a spherical symmetrical field. Treating HCl as being formed from H+ and Cl- we have a proton embedding itself in a 'cloride ion' with a noble gas configuration. This causes the electrons to distort (they're attracted towards the proton). Effectively the bonding is due to all the orbitals contributing. However the ones with more electron density between the H and Cl nuclei contribute more. To describe the situation as s, p, or sp1 2 or 3 is a gross simplification. Attempting to use this simplified model causes the confusion you are experiencing. In general hybridisation as a model works well when explaining known structures eg ethene, methane.

What I'm trying to say that it 'works' as an explanation - but has less value as a predicitive tool.

As regard O2 - you can create a MO diagram with or without hybridising - as someone mentioned above usually hybridisation is used to create orbitals that have the most similar energy - since these are assumed to bond best. In general orbital symmetry is important when constructing MO diagrams. You could use two p orbitals and a sp orbtial (per atom)- that seems like an obvious choice.

This would give (per atom) one sp orbital occupied (2e) giving a lone pair, one sp orbital bonding between atoms (1e per atom) and the remaining 3 electrons per atom being placed on the doubly degenerate p orbitals (this is how they will probably do it in text books note the third electron goes into an antibonding orbital). This gives bond order 2 and one unpaired electron per atom. However to imagine that the unpaired electron is somehow confined to the a p orbitals is of dubious merit.

However you could construct the diagram using one p orbital and one sp2 orbital (in this case you need to decide if a sp2 orbital points between the two O atoms or if two of the three sp2 orbitals straddle the O-O centre line.)

In the first case you can imagine (per atom) 1e on the p orbital (pi bonding), 1e on the sp2 orbital between the two oxygens (bonding) - this leaves 4 electrons per atom to be distributed between the two sp2 orbitals pointing away from the O-O 'bond'. As these two sp2 orbitals are degenerate (and therefore the same energy) they each get 2 electrons giving two lone pairs. This gives bond order two and no unpaired electrons.

The second case probably would have (per atom) 1e in the p orbital (pi bonding), 2e in the sp2 orbital pointing away (lone pair) and the remaining 3 going into the bent bonding sp2 orbitals giving a total bond order 2 and one unpaired electron per atom.

Note these three arrangements do not give the same results.. However note that using sp2 hybrids results in lower symmetry (similar to ethene) than using sp hybrid (like acetylene or nitrogen) - In general you can assume that the most symmetrical situation is favoured (ask someone else why maybe?)

In addition there's no reason why you shouldn't create a MO diagram using sp3 orbitals (with 3 lobes of the sp3 orbitals forming 'straddling' bonds (similar to pi bonds) - note this situation has the same symmetry as the sp hybrid case and so should be indentical.

Hope that made o2 a bit clearer - I wouldn't get hung up on this stuff though - it's very abstract and possibly not really much use even if you do understand it (though somepeople make a living out of it writing books etc I assume.)HappyVR 01:27, 17 June 2006 (UTC)

Carbon-14 detection threshhold

What are the minimum number of atoms that the most sensitive method of carbon-14 detection requires in order to make a reliable determination that carbon-14 is or is not present, i.e., the threshhold detection amount? ...IMHO (Talk) 17:41, 13 June 2006 (UTC)

Based on radiocarbon dating, it would seem to be more a question of relative concentration. The section in question notes lower bounds on total carbon per sample but there's no suggestion that a larger sample (i.e. more carbon atoms) yields a longer dateable timespan. — Lomn 18:39, 13 June 2006 (UTC)

Modern carbon-14 detection uses accelerator based mass spectrometry, so if there is a single carbon-14 atom in the ionised sample, it will be detected. But, that probably wasn't your ideal answer. If you wanted to know about the minimum beta emission detection masked by background radiation, the article on radiocarbon dating says that the threshold age is 58000 to 62000 (which is silly, since it depends on the size of the sample). That is 10.5 half-lives, so the maths is pretty simple, provided the original sample size is known.--Eh-Steve 18:46, 13 June 2006 (UTC)

What I am trying to find out is if we started with a mole of pure carbon-14 (or 14 grams or "sample size" or the maximum possible amount of carbon-14 in the organism when it stopped breathing, although in reality far less than 14 grams.) at what point would our Beta test equipment be unable to do its job due to the lack of sufficient emissions assuming the spectrographic analysis would always be able to do its job.

• Further reading suggests the point I am looking for is the point where Background Radiation is too great for the emissions from c-14 to be distinquished. Does anyone know where that point is in terms of number of c-14 atoms or is it just an arbitary point that varies with other variables like equaipment sensitivity, etc.? Also does anyone know the maximum possible amount of c-14 or what the 100% value of c-14 is? ...IMHO (Talk) 23:37, 13 June 2006 (UTC)

• (Please note that the data in the table below contains errors of computation attributed to the use of inferior programming language.) ...IMHO (Talk) 20:11, 14 June 2006 (UTC)

(Get PARI-GP_computer_algebra_system for big integer correctness. --GangofOne 02:07, 16 June 2006 (UTC))

Carbon-14 vs.Nitrogen-14 (number of atoms)

Years	Carbon-14	Nitrogen-14
0	602,214,150,000,000,000,000,000	0
5,730	301,107,075,000,000,000,000,000	301,107,075,000,000,000,000,000
11,460	150,553,537,500,000,000,000,000	451,660,612,500,000,000,000,000
17,190	75,276,768,750,000,000,000,000	526,937,381,250,000,000,000,000
22,920	37,638,384,375,000,000,000,000	564,575,765,625,000,000,000,000
28,650	18,819,192,187,500,000,000,000	583,394,957,812,500,000,000,000
34,380	9,409,596,093,750,000,000,000	592,804,553,906,250,000,000,000
40,110	4,704,798,046,875,000,000,000	597,509,351,953,125,000,000,000
45,840	2,352,399,023,437,500,000,000	599,861,750,976,563,000,000,000
51,570	1,176,199,511,718,750,000,000	601,037,950,488,281,000,000,000
57,300	588,099,755,859,375,000,000	601,626,050,244,141,000,000,000
63,030	294,049,877,929,688,000,000	601,920,100,122,070,000,000,000
68,760	147,024,938,964,844,000,000	602,067,125,061,035,000,000,000
74,490	73,512,469,482,421,900,000	602,140,637,530,518,000,000,000
80,220	36,756,234,741,210,900,000	602,177,393,765,259,000,000,000
85,950	18,378,117,370,605,500,000	602,195,771,882,629,000,000,000
91,680	9,189,058,685,302,730,000	602,204,960,941,315,000,000,000
97,410	4,594,529,342,651,370,000	602,209,555,470,657,000,000,000
103,140	2,297,264,671,325,680,000	602,211,852,735,329,000,000,000
108,870	1,148,632,335,662,840,000	602,213,001,367,664,000,000,000
114,600	574,316,167,831,421,000	602,213,575,683,832,000,000,000
120,330	287,158,083,915,710,000	602,213,862,841,916,000,000,000
126,060	143,579,041,957,855,000	602,214,006,420,958,000,000,000
131,790	71,789,520,978,927,600	602,214,078,210,479,000,000,000
137,520	35,894,760,489,463,800	602,214,114,105,240,000,000,000
143,250	17,947,380,244,731,900	602,214,132,052,620,000,000,000
148,980	8,973,690,122,365,950	602,214,141,026,310,000,000,000
154,710	4,486,845,061,182,980	602,214,145,513,155,000,000,000
160,440	2,243,422,530,591,490	602,214,147,756,577,000,000,000
166,170	1,121,711,265,295,740	602,214,148,878,289,000,000,000
171,900	560,855,632,647,872	602,214,149,439,144,000,000,000
177,630	280,427,816,323,936	602,214,149,719,572,000,000,000
183,360	140,213,908,161,968	602,214,149,859,786,000,000,000
189,090	70,106,954,080,984	602,214,149,929,893,000,000,000
194,820	35,053,477,040,492	602,214,149,964,947,000,000,000
200,550	17,526,738,520,246	602,214,149,982,473,000,000,000
206,280	8,763,369,260,123	602,214,149,991,237,000,000,000
212,010	4,381,684,630,061	602,214,149,995,618,000,000,000
217,740	2,190,842,315,030	602,214,149,997,809,000,000,000
223,470	1,095,421,157,515	602,214,149,998,905,000,000,000
229,200	547,710,578,757	602,214,149,999,452,000,000,000
234,930	273,855,289,378	602,214,149,999,726,000,000,000
240,660	136,927,644,689	602,214,149,999,863,000,000,000
246,390	68,463,822,344	602,214,149,999,932,000,000,000
252,120	34,231,911,172	602,214,149,999,966,000,000,000
257,850	17,115,955,586	602,214,149,999,983,000,000,000
263,580	8,557,977,793	602,214,149,999,991,000,000,000
269,310	4,278,988,896	602,214,149,999,996,000,000,000
275,040	2,139,494,448	602,214,149,999,998,000,000,000
280,770	1,069,747,224	602,214,149,999,999,000,000,000
286,500	534,873,612	602,214,149,999,999,000,000,000
292,230	267,436,806	602,214,150,000,000,000,000,000
297,960	133,718,403	602,214,150,000,000,000,000,000
303,690	66,859,201	602,214,150,000,000,000,000,000
309,420	33,429,600	602,214,150,000,000,000,000,000
315,150	16,714,800	602,214,150,000,000,000,000,000
320,880	8,357,400	602,214,150,000,000,000,000,000
326,610	4,178,700	602,214,150,000,000,000,000,000
332,340	2,089,350	602,214,150,000,000,000,000,000
338,070	1,044,675	602,214,150,000,000,000,000,000
343,800	522,337	602,214,150,000,000,000,000,000
349,530	261,168	602,214,150,000,000,000,000,000
355,260	130,584	602,214,150,000,000,000,000,000
360,990	65,292	602,214,150,000,000,000,000,000
366,720	32,646	602,214,150,000,000,000,000,000
372,450	16,323	602,214,150,000,000,000,000,000
378,180	8,161	602,214,150,000,000,000,000,000
383,910	4,080	602,214,150,000,000,000,000,000
389,640	2,040	602,214,150,000,000,000,000,000
395,370	1,020	602,214,150,000,000,000,000,000
401,100	510	602,214,150,000,000,000,000,000
406,830	255	602,214,150,000,000,000,000,000
412,560	127	602,214,150,000,000,000,000,000
418,290	63	602,214,150,000,000,000,000,000
424,020	31	602,214,150,000,000,000,000,000
429,750	15	602,214,150,000,000,000,000,000
435,480	7	602,214,150,000,000,000,000,000
441,210	3	602,214,150,000,000,000,000,000
446,940	1	602,214,150,000,000,000,000,000
452,670	0	602,214,150,000,000,000,000,000

bios viruses

hi my old laptop has not worked for a month for so now its a bit expencive to get fiexd, so i lent it to a friend who sead they would look at it. they say it has a bios virus, i was wondering what a bios virus is?

That would be a Computer virus which has somehow affected your computer's Basic Input Output System. The BIOS is a small program that tells your computer how to startup. Although BIOS viruses are said to be rare, once your BIOS has been corrupted, there is not much that can be done. The term itself is a little misleading, as the virus does not "live" in the BIOS and can not replicate itself from there. But if your computer has been affected, the terminology is the least of your worries. --LarryMac 20:33, 13 June 2006 (UTC)

Resetting the CMOS just might work. Not sure, though. -- Миборовский 05:53, 14 June 2006 (UTC)

How do you reset the CMOS? --Silex 21:02, 14 June 2006 (UTC)

Laptops are tough. CMOS is located on your motherboard so you either have to open it up to expose the motherboard (NOT recommended) or ask your Dell/IBM/HP guy. -- Миборовский 22:27, 14 June 2006 (UTC)

Well where does the BIOS virus reside if it does not 'live' in the BIOS? And would 'flashing the CMOS' work? To do that, do I have to jump some pins or something? --217.44.0.212 10:56, 17 June 2006 (UTC)

someone has reposted this question below, I'm adding my reply both places

Reccommended procedure:

1. Verify the claim that there is a problem with the bios. To do this, you might check if the laptop boots normally with a bootable CD such as knoppix. If this is successful, the problem is probably not with the bios.
2. If you want to restore bios factory defaults, you can normally do this from within the menus of the bios setup program. If you pay close attention while the pc starts its boot sequence, you will see a message which tells you how to open the setup program (it might be, for example, holding down the F2 key when the pc starts). A text mode setup program will open, with a menu. Somewhere, usually on the "Exit" menu, there is an option "Load Setup Defaults". If you are certain that the bios is messed up, this should restore it. You also need to "Save changes" before exiting. --vibo56 ^talk 14:00, 17 June 2006 (UTC)

Proportionality / Physics of a shiny black shoe

Hello,

I am taking my final A-level physics paper in a couple of days and one section of the exam focuses on how well we can use our knowledge of physics drawn together for situations that aren't explicitly taught in our course. To get to the point, one of the questions from a previous paper asks us to explain how it is possible for a shoe to be shiny and black, which conflict from my understanding since black absorbs light, but for something to be shiny light must be reflected. I guessed that some white light must be reflected at the parts that appear shiny, but I had trouble putting it into words and explaining it properly. I also couldn't find any articles that were relavant to this.

For my second question, and I apologize if it is answered in the Proportionality_(mathematics) article, would a be proportional to b if $a=kb+c$ and c was non-zero? Or are two quantities only proportional if one equals 0 when the other is also 0? Thanks very much, Krackpipe 20:17, 13 June 2006 (UTC)

Just to answer the second question, it's only actually proportional if c=0. But for c non-zero you can still talk about it being "linearly related". Arbitrary username 20:24, 13 June 2006 (UTC)

The short answer to the first question is, there is still a lot of light reflected from a black object. It is just a lot less than from the objects around it. Walt 20:28, 13 June 2006 (UTC)

(edit conflict) Re the first question, there is a little specular reflection, but what doesn't get reflected specularly is almost all absorbed. If instead there was a little diffuse reflection and the rest was absorbed, then you'd probably describe the color as dark gray (at least if the reflectivity was reasonably wavelength-independent within the visible spectrum). Arbitrary username 20:30, 13 June 2006 (UTC)

Indeed. A shiny black surface consists of a shiny surface, which specularly reflects some of the light, over a black material that absorbs (most of) the rest. These don't have to be different materials, but often they are. To be shiny, a material has to have a smooth surface and a high index of refraction (for details, see Fresnel reflection). In case of a black shoe, the shiny layer presumably consists mostly of shoe polish, whereas in the case of, say, obsidian, the glass both reflects light that hits its surface and rapidly absorbs any light that doesn't get reflected. —Ilmari Karonen (talk) 22:52, 13 June 2006 (UTC)

Formula for heptyl rocket fuel

A few weeks ago heptyl rocket fuel was in the news. What is the chemical structure of heptyl?

I'm not sure about the rocket fuel per se, but heptyl is the substituent form of the seven-carbon alkane heptane. Isopropyl 00:02, 14 June 2006 (UTC)

June 14

Adjusting Depth Of Feild On Regular Digital Camera

Is it possible to achieve depth of field effects (where parts are out of focus) without an SLR? They're just too big and inconvenient, not to mention expensive. Are there any digital cameras with a single lens that will allow me to control depth of field by varing the position of the lens? -Username132 (talk) 14:18, 12 June 2006 (UTC)

It's nasty with the smaller digital cameras, but at least you can try lots of times, and delete the losers. Almost all of these cameras lock their focus and aperature on a 'half click', you then move the camera to the subject and do a full press. For reduced depth of field you need dimmer light so the camera opens up more. You could lock the camera in a shadow, and then take a picture in brighter light, but then you would have to do some post-processing on the computer. --Zeizmic 15:06, 12 June 2006 (UTC)

In other words, it's a function of aperture size; the larger the aperture the greater the depth of field effect, which means that this effect is better with a larger lens such as those found on SLRs.--Shantavira 15:21, 12 June 2006 (UTC)

Any camera which allows you to set the aperture size will be able to vary the Depth of field. However, the smaller size of the imaging device may limit what is possible. Assuming one has a camera with the capability, then taking a series of pictures of the same subject, varying the F stop in each one, should reveal the capabilities of that particular camera. --LarryMac 15:44, 12 June 2006 (UTC)

The perceived effect also depends a lot on the focus distance: the easiest way to get nice blurry backgrouds with a compact is simply to switch to macro mode and get real close to the target. That way you maximize the ratio of background and foreground distance.

Also, digicams can do absurdly short exposures. In the fully automatic mode ("P" or "auto") the camera may try to balance the aperture and the exposure time, but if you want you can switch to aperture priority mode ("A") and shoot at the maximum aperture (i.e. smallest f number) in pretty much any lighting just fine. —Ilmari Karonen (talk) 15:53, 12 June 2006 (UTC)

Simply, to reduce field of focus: use maximum aperture - if that is what you can set; or: use fastest speed - if that is what you can set. The latter forces the camera to open the lens as much as possible. The technique you describe of "moving the lens" I presume to mean "zooming" i.e. altering the focal lenght of the lens system. If that is your only option, then using the maximum "zoom in" for an object a fixed distance from you will reduce the depth of field. --Seejyb 22:01, 12 June 2006 (UTC)

Zooming in might be counterproductive, though. My digital camera, for example, has an aperture range of f/2.6 to f/8.0 when zoomed all the way out, but only f/5.6 to f/8.0 when zoomed all the way in. --Serie 00:11, 13 June 2006 (UTC)

Also, many digital cameras won't focus very close, even in macro mode, unless zoomed all the way out. That, combined with the aperture range issue, means it's often better to zoom out and get close to the subject than to zoom in and shoot from further away. Of course, that only works if the subject is a) inanimate, b) slow, or c) tame. —Ilmari Karonen (talk) 11:50, 13 June 2006 (UTC)

It's very, very hard to get significant depth of field effects in compact digital cameras, even if they have manual aperture controls (and some of the better models do). As our depth of field article explains, the depth of field is larger with a smaller film (or sensor). Compact digitals have tiny sensors compared to digital SLRs, let alone 35mm film. Maybe you could buy a second-hand film SLR for the purpose if you are specifically setting out to take advantage of this effect? --Robert Merkel

Adding onto what has already been said, if you can't directly change your aperture or shutter speed settings, your camera may have a "Portrait" mode or similar mode where the camera attempts to limit the depth of field. Your camera manual should explain more on this.--Tachikoma 04:22, 13 June 2006 (UTC)

See here, basically get as close to your subject as possible, use as long focal length as possible and use the largest aperature. Can be done, but much easier with a SLR. Stefan 09:19, 13 June 2006 (UTC)

Question

There is a compact camera on ebay with Focal Length 7.7-23.1mm f/2.8-4.9 (35mm film equivalent: 37-111mm) - looking at the depth of field article, I will have a depth of field limited to only close up subjects. Look at the example photos my f/ numbers are restricted between 2.8-4.9 which means I can take the second daffodil picture and the cat picture only. I clearly have misunderstood. Explain how, please?

What can I acheive with; • F2.8 / F3.2 / F3.5 / F4.0 / F4.5 / F5.0 / F5.6 / F6.3 / F7.1 / F8.0 (wide) • F4.1 / 4.5 / 5.0 /5.6 / F6.3 / F7.1 / F8.0 (tele) ? --Username132 (talk) 23:46, 13 June 2006 (UTC)

• Going for a compact camera will not allow you to achieve much when it comes to Depth of field. If you really want to be able to go artistic but don't want an slr, there are many cameras out there with an APS Size sensor many manual controls (thats what you want) and good lens quality without interchangeable lenses. I leave you with a quote from the wiki to explain

...this means that smaller cameras have deeper depth of field than larger cameras. This can be an advantage or disadvantage, depending on the desired effect. A large format camera is better for photographs where the foreground and background are blurred (cf. bokeh), while a small camera maximizes depth of field, so that objects behind or in front of the focus plane are still in good focus. This difference between formats goes away if the cameras are compared with equal aperture diameters rather than equal f-numbers; but the smaller camera can not usually use a large aperture diameter, so can not achieve a very limited depth of field.

--DennyCrane Talk 05:13, 14 June 2006 (UTC)

Are you saying that f/2.8 on one camera isn't the same as f/2.8 on another? --Username132 (talk) 23:41, 14 June 2006 (UTC)

f/2.8 is always f/2.8, but 50mm is not always 50mm (sortof) or rather it is BUT to get the same field of view on a camera with a smaller sensor you need a lens with shorter focal length. So compact digital cameras can have a lens from 7.7-23.1mm (as above) wich is equivalent of 37-111mm for a full frame 35mm film camera, and f/2.8 at 7.7mm will have much more depth of field than at 37mm. Stefan 15:31, 16 June 2006 (UTC)

Measuring mass

How would you measure (not calculate using the density) the mass of an object in 0g?Yanwen 00:58, 14 June 2006 (UTC)

Apply a known force, and measure the acceleration. EdC 01:35, 14 June 2006 (UTC)

Attach it to a spring and then let it oscillate. See last equation in this section. I think that's how they do it in space. WP 03:40, 14 June 2006 (UTC)

But those are a pain to calibrate

Centrifuge it at a known speed, perhaps? 205.132.76.4 16:14, 16 June 2006 (UTC)

Your question is somewhat ambiguous:

• If, by the expression in 0g, you mean 'a place where the gravitational force is exactly 0', then there is no such place anywhere in the known, observable universe, and the question is somewhat hypothetical.

• If, on the other hand, you mean to designate a place 'inside an artificial satellite', such as the Space Shuttle, then be warned that this expression constitutes an abuse of language as the actual gravitational force is not nul: the satellite and the object whose mass you want to measure, inside this satellite, both fall towards the Earth with the same acceleration. So there is no apparent acceleration associated with the fall of the object, when measured with respect to the satellite walls, but that's not to say there is no gravity.

I don't think a single coil spring would work very accurately. However, attaching the mass between two springs arranged linearly like this:

||=/\/\/\/\/\=(object)=/\/\/\/\/\=||

where = stands for a fixed link, || represents the satellite walls (or some structure fixed with respect to the satellite walls), and /\/\/\/\/\ is a spring of know constant, would provide a suitable simple experimental setup. If the object is then displaced some small amount along the linear axis, measuring its position as a function of time would allow you to retrieve the mass, knowing the properties of the springs, the initial conditions and the time evolution of the system. --Michel M Verstraete 21:30, 19 June 2006 (UTC)

Fibre Optics

What is the difference between FOBOT and Patch Panel?

Tilt in the Earth's axis

Is there a "physics" explanation to the fact that the earth's axis is tilted?

Yvan Dufour

Why is not addressed, but you may be interested in Axial tilt. -- Rick Block (talk) 04:48, 14 June 2006 (UTC)

MadSci network has answered to similar questions here and here. –Mysid^(t) 07:29, 14 June 2006 (UTC)

The angle of the Earth's axis to its plane of orbit may in part be due to the hypothetical impact with Theia 4.5 billion years ago, resulting in the formation of the Moon (see Moon, Giant impact hypothesis, and History of Earth#Moon for more information). — Knowledge Seeker দ 04:46, 15 June 2006 (UTC)

Flying Saucer

I remember hearing somewhere that people were researching a type of craft that spun rapidly lifting it into the air. My question is has anyone ever heard of this or am I just crazy? If you have heard of it is there any kind of link you could give me to further my quest?

See Military flying saucers, but don't discount the possibility that you could, indeed, be crazy.  freshofftheufoΓΛĿЌ  05:31, 14 June 2006 (UTC)

I definately remember hearing about this, and progress having been made recently on a non-military version. I can have a look for details. Skittle 08:57, 14 June 2006 (UTC)

See also British Rail flying saucer. —Ilmari Karonen (talk) 17:47, 14 June 2006 (UTC)

See also Frisbee. SamSim 10:50, 16 June 2006 (UTC)

Thank You

Bacteria ...

Hi!Mysid & zafiroblue05, thanks for the answers on dna. I have doubts regarding the answers of the following questions on bacteriology :

1. Do both Thermoplasma & Mycoplasma lack a CELL-WALL?
2. How can a thermophilic bacterium be isolated & collected from a running hot-water spring ?
3. In a broth culture, why does Staphylococcus sp. grows

throughout the whole medium, while Pseudomonas sp. grows as a thin film at the broth surface ? - Pupun.

1. All bacteria have peptidoglycan cell walls.
2. Get a water sample, spread-plate, incubate at high temperature.
3. Staph is gram-positive and Pseudomonas is gram-negative? But I truly have no idea.

-- Миборовский 05:51, 14 June 2006 (UTC)

1. Thermoplasma and Mycoplasma both lack cell walls. "L-forms" (which have no cell walls) of other bacteria which usually have cell walls, can be induced by various culture media and antibiotics.
2. Dunno, but you should look at the literature to see what media have been used. As Miborovsky points out, temperture will be key.
3. Dunno, but Pseudomonas is noted for its motility characteristics, including swimming, swarming, and twitching, which result in its tendency to form films. It might also have something to do with oxygen tension at the surface vs. the rest of the medium. - Nunh-huh 06:18, 14 June 2006 (UTC)

For question 1 & 2: I know that one D Lovely, a researcher at the University of Massachusetts, has done extensive research in thermophilic and hyperthermophilic archea. You might try searching PubMed for his name, or for keywords like "hot-water spring" and "thermophile" . One thing to note: you used the word "bacterium" in your question. Tou are correct to use this word in that "bacteria" (not capatalized) describes all single-celled prokaryotic organisms. However, Bacteria (capatalized), the phylogenetic group, represents a very small section of high-temperature flora. Most thermophiles (indeed, most extreme-environment microorganisms) belong to the group Archaea. Also, and this is important for your answer to Q1, Archaea do not have peptidoglycan cell walls, they have cell walls comprised of other chemicals (some of which, however, resemble peptidoglycan, such as N-acetyltalosaminuronic acid). Though most single celled prokaryores have a cell wall, it turns out that Mycoplasma and Thermoplasma do not, they are pretty much the only little-b bacteria that lack these (Mycoplasma are Bacteria, Thermoplasma are Archaea). For question 3: What kind of media are you using? Factors like light availiability (light energy is more available near the edges, but remember that borosilicate glass blocks most UV), oxygen availability (environmental gasses will be more availiable at the environment/media interface), movement (movement at the media/container interface will encourage biofilm formation) etc. will induce separation of the species in your sample. The biggest question here, really, is are you using a rocker plate/roller to incubate your culture?Tuckerekcut 19:04, 14 June 2006 (UTC)

Television,Broadband&Media

What is a longform of "RiTV" which is an interactive television,broadband & media solution ? Is there any special video codec of RiTV ? Thanks!

Background music in Blogger

Hi is it possible to add background music to a blogger website (www.blogger.com)? If so, how do you do it? Thanks.

If it uses plain HTML is some form, you should be able to use an <embed> tag to do it, however I would suggest that doing it isn't a good idea because 1. Not everyone is on broadband, and adding music to a page (especially in a format like .mp3 or .wav as opposed to midi) will add a lot to the loading time, and 2. if someone is trying to listen to their own music and your blog starts playing something else, they are likely to get a little cheesed off. Confusing Manifestation 13:50, 14 June 2006 (UTC)

People tend to get annoyed when a web site starts making noise at them. This is why banner ads that include sound are so incredibly unpopular. --Serie 22:18, 14 June 2006 (UTC)

train noise

I live under the manhattan bridge in brooklyn ny.and the noise from the trains constantly going overhead is deafining.what i would like to know is if the trains were to slow down to 5 miles per hour,how much would that cut down the noise level?it seems the the slower moving trains do not make as much noise.are there any studies to support this...thanks bill vitiello i can be reached at either 718-237-8700 or by e-mail at bill <email removed to prevent spam>

Intuitively, it makes sense that slower-moving trains are quieter than faster ones, but it's not obvious to me that there is a simple model to predict how the noise levels will be affected because there are everal components to the noise, as well as the effect that changing pitch has on the perceived loudness. So, if you have various trains going at different speeds affecting you in your house, perhaps the most sensible thing to do would be to buy a sound level meter (usually called a decibel meter) and measure the difference. You might be able to get one on eBay for a relatively modest cost.

One other silly question - have you considered soundproofing? --Robert Merkel 13:47, 14 June 2006 (UTC)

LOL, you've never lived under a subway.. and no, I'm pretty sure they're louder when they slow down--205.188.116.74 15:23, 14 June 2006 (UTC)

Don't forget, if you do try and the trains to slow down just by the bridge, you'll probably get more noise, as the squeaky brakes come on just before, and the noisy motors have go at extra power to accellerate back up to normal speed. And, although the clanking/creaking noise may be quieter, it would be sustained for longer as the train would take longer to pass over your house. smurrayinchester^{(User), (Talk)} 17:57, 14 June 2006 (UTC)

Lived under a subway? like, in a sewer or something? Philc _T^E_C^I 20:45, 14 June 2006 (UTC)

Uh, a good part of Brooklyn uses elevated tracks--152.163.100.74 23:20, 14 June 2006 (UTC)

Strange maybe it should be called the sub/supway. Philc _T^E_C^I 11:16, 15 June 2006 (UTC)

Well at worst they'd call it an "elevated subway" I guess. But the anonymous user was clearly talking about a regular subway, and he was quite correct in assuming that you'd never lived under a subway, as with everyone else.  freshofftheufoΓΛĿЌ  11:40, 15 June 2006 (UTC)

No, actually that's absurd, virtually all of the outer boroughs have elevated subway lines, and a great many people do live "under" them, not literally of course, as most are directly over streets and intersections, but in the case of the Manhattan Bridge, on the Brooklyn side they become elevated just a few blocks before they reach the bridge and are in fact over a number of buildings, I always assumed that area was mostly just warehouses though, never really payed much attention to what was under the tracks honestly--205.188.116.74 21:11, 15 June 2006 (UTC)

Just for clarity, above ground subways are regular subways, and contrary to popular belief, the Manhattan Bridge is actually an above ground bridge--205.188.116.74 21:27, 15 June 2006 (UTC)

An above ground subway is not "regular", that would be a railway, the word subway is derived from the fact it is underground. Philc _T^E_C^I 01:16, 17 June 2006 (UTC)

yes, but above ground subways are standard, other than Manhattan there aren't many boroughs with extensive underground tunnels, but they've still always been considered subways, I can't really imagine why anyone would find that strange--172.150.116.206 05:06, 17 June 2006 (UTC)

• ah - lightbulb moment I am the person who said "you've never lived under a subway.. ", and what I was trying to imply is that if you think you can sound proof an apartment against a subway, then you've obviously never heard one--172.150.116.206 05:09, 17 June 2006 (UTC)

Don't use earplugs either. They can lead to serious ear infections. ...IMHO (Talk) 18:24, 14 June 2006 (UTC)

world

--24.239.38.206 14:55, 14 June 2006 (UTC)Nick S.What are the major theories of how the world started?

Please see world for possible theories. General Eisenhower • (at war or at peace) 16:17, 14 June 2006 (UTC)

Isn't it obvious? The world started with some Lincoln Logs and a sliding glass door when I was about 4 years old. That's why I have no memory of it before then. --Kainaw ^(talk) 17:19, 14 June 2006 (UTC)

The philosophy Kainaw just illustrated is called solipsism, in case anyone was wondering. —Keenan Pepper 01:55, 15 June 2006 (UTC)

The scientific theory is that the Earth condensed out of the solar nebula along with the Sun and other planets, about 4.6 billion years ago (see, for instance, History of Earth#Origin). Many religions have their own stories of the creation of the Earth, which their adherents accept in varying degrees. Many people believe that God created the universe and Earth directly, much more recently than the scientific evidence suggests. — Knowledge Seeker দ 04:44, 15 June 2006 (UTC)

Surely "Some people believe that a god or gods created the universe and Earth directly, much more recently than evidence suggests"? Personally, I like the idea that the Earth hatched out of a giant egg about 3 generations before written history began... Skittle 12:30, 15 June 2006 (UTC)

My favorite theory is from Babylonian mythology. It's called the Enûma Elish, and in short, the god Marduk fights the evil dragon Tiamat, then uses her remains to create the world. Mind you, it's not what I believe actually took place, but it makes for a great story.--Tachikoma 16:16, 17 June 2006 (UTC)

career in science

what is the most widely chosen field of study in science??

thanks!

most people choose to make a metric boat-load as doctors. the relationship between choice and reality is left as an exercise.

The FDA has been tapping my phone calls

what if any scientific counter measures can you think of to keep them from monitoring my phone calls? —Yi^pe 15:35, 14 June 2006 (UTC)

Disconnect your phone line. Electrons are incapable of bridging a several-foot gap with that little voltage. Black Carrot 16:55, 14 June 2006 (UTC)

By "scientific", do you mean "encryption"? Encryption only works if you encrypt/decrypt at both ends. Even if you use VOIP, both ends have to be on the Internet. You can't drop to a regular, unencrypted phone line anywhere. The easiest option: use someone else's phone (like a pay phone at a restaurant). Of course, the people you are talking to are also probably tapped. --Kainaw ^(talk) 17:05, 14 June 2006 (UTC)

The FDA doesn't have the power to tap phone. Perhaps you are thinking of the FBI? Besides which, how would you know? But the only real answer is not to use the phone and arrange some other method of communication. Or I suppose you could arrange to talk in code: "The rooster lands at midnight, next to the pumpkin".  ;-) Dragons flight 17:15, 14 June 2006 (UTC)

The FDA would be very interested in knowing exactly what Yipe plans on doing with the rooster and the pumpkin. Very interested... I'd recommend talking about US submarine movements instead, which the FDA couldn't care less about. — Asbestos | Talk (RFC) 17:38, 14 June 2006 (UTC)

ant .5 mm

All I could make out while it was moving was the black head. (~.5 mm)

Is there an ant that is only about half a millimetter long? ...IMHO (Talk) 17:18, 14 June 2006 (UTC)

You mean the real tiny black ones that commonly invade homes? They are dried and used as a pepper replacement by people who like to eat insects. They are rather spicy. --Kainaw ^(talk) 17:21, 14 June 2006 (UTC)

Hey for real??? What do you call it ant pepper? ...IMHO (Talk) 17:45, 14 June 2006 (UTC)

The ones that commonly invade people's homes are certainly not 0.5 mm long, which is only .02 inches, barely visible. Unless you get really tiny ants at home. I don't know of any ants that small, but I'm not an expert. The ants atricle suggests the low end is 2mm, four times as large. — Asbestos | Talk (RFC) 17:41, 14 June 2006 (UTC)

What ever they are they show up at the same time as the larger ants (2-3 mm) in as many numbers and travel just as fast or even faster. ...IMHO (Talk) 17:48, 14 June 2006 (UTC)

The last ants I had in my house were so small that I only saw them when they walking in a line. I had to get really close to see the little specks crawling up from under the back door, to the kitchen counter, and across to the sink. I assume they were ants because they behaved like ants. I didn't put one under a magnifying glass to ensure it was an ant. When I described them at work, others said they have had the extremely tiny ants in their houses as well. Perhaps they are some other bug that likes to walk in long lines like that. Oh - and seriously - black ants are used as a pepper-like substitute. I wouldn't suggest eating ones in your back yard. They are full of pesticides. --Kainaw ^(talk) 17:50, 14 June 2006 (UTC)

Yeah I haven't looked at them under a magnifier yet either and they are too small for my camera unless I can rig up a magnifier somehow in front of the lens. Chances are the camera will take a picture of the magnifier instead. Anybody got any ideas? I can't afford another camera. ...IMHO (Talk) 18:04, 14 June 2006 (UTC)

A quick Google search yields some fascinating results, though nothing conclusive: [[5]] [[6]] [[7]] [[8]] Black Carrot 22:32, 14 June 2006 (UTC)

They are probably the Thief ants then and do turn out to be a liitle larger since all you see when they are moving is the black part of their body - not legs, antenna, middle or rear. Once stopped and put under a nagnifier next to a .5 mm scale stretched to 1.5 mm but that is still very small compared to other ants. I'll try get a picture posted. The one I just had got up while I was typing and hid somewhere. Go figure! ...IMHO (Talk) 01:24, 15 June 2006 (UTC)

Young's two-slit experiment

Hi guys, I've had a look in the articles to no avail. I have a question about the equation for this experiment.

What I want to know is that if we use a wave of amplitude 3.0 cm and subsequently a slit width of 3.0 cm to ensure maximum diffraction, and have the gap between the slits of 10 cm (big I know), what is the slit separation?

Bad character drawing:

,,,,,,,---3.0cm-gap---,,,,,,,,,,,,,,,,,,,,10cm,,,,,,,,,,,,,,,,,,,,---3.0cm-gap---,,,,,,,

Is it 10 cm between the inside corners of the gap or 13 cm from centre of gap to centre of gap? any help appreciated, thanks. Anand 17:32, 14 June 2006 (UTC)

I believe the separation is measured from the center of the hole, and so it would be 13 cm. After all, the semi-circular waves emerging from the holes are centered on the center of the circle. I'll see if I can't find a more authorative ciation, though. — Asbestos | Talk (RFC) 18:02, 14 June 2006 (UTC)

Found some references: In this lab sheet, they note the separation is measured center-to-center. And in here and here they explicitly refer to the "center-to-center" separation. — Asbestos | Talk (RFC) 18:14, 14 June 2006 (UTC)

I really think it should be measured center to center. At least that's how used to do it. Afonso Silva 21:47, 14 June 2006 (UTC)

Centre-to-centre it is then. Thanks guys. Anand 21:50, 14 June 2006 (UTC)

Opera Web Browser and Flash Blocking

Opera browser doesnt have a flash blocker or something like that like firefox has a plugin, Abrowser has it. So is it possible to do so in opera? Also in opera, when webpages are saved, all of that pages are saved in the same folder, without a new folder being created with the name "xyz_files". So this is also really annoying bcoz the clutter increases in the folders. So does anyone have a solution to above two problems?

To block Flash, hit F12 to pop up the quick preferences menu, and uncheck the 'Enable plug-ins' item. This is a bit of a sledgehammer approach because it will also disable all other plug-ins; in practice, I find that my web experience is very rarely harmed by the absence of plug-ins. (Actually, browsing tends to be faster and less annoying.) If you want to see a plug-in – Flash or otherwise – just hit F12 and recheck the 'Enable plug-ins' option. (You may need to refresh the page by hitting F5, too.) This is what I do, at least. TenOfAllTrades(talk) 19:27, 14 June 2006 (UTC)

yeah theres userspace javascript for all ad-blocking flash-blocking etc on opera, just gogle for it. then you can right click an element and block it (it disappears form the page) or you can block all content from that server (if its an adserver). for the second question theres probably no simple solution, you should make a script (perl etc) that archives into a folder immediately after you save a page.

New body

Is it true that every human has a completely new body about every seven years? That is, repair and replacement of materials mean that our body today is composed of completely different atoms from the body of seven years ago (unless, of course, some of those old atoms have come back). I have heard this is literally true, and so includes the bones and the brain. How remarkable that we would have, for a lifetime, the same form, scars and memories, yet the physical body is continually replaced. Thanks for your help. 66.213.33.2 19:40, 14 June 2006 (UTC)

You are probably refering only to tissue since metals like arsenic can accumulate in the human body over periods of time that are much longer than 7 years. ...IMHO (Talk) 19:45, 14 June 2006 (UTC)

Different cells (and tissues) are replaced at different rates. A paper published a couple of years ago in Cell ("Retrospective birth dating of cells in humans") looked at the amounts of carbon-14 in the DNA of various body tissues. (See also the Scientific American summary: [9].) Because the amount of carbon-14 we were exposed to spiked in the late fifties and early sixties (due to atmospheric testing of atomic bombs) cells that date to that era will contain a higher proportion of carbon-14 than cells made before or after that time. Various other experiments have established lifetimes for shorter lived tissues and cells. Here's a rough idea of the time scales involved.

• Cells lining the gut last three to five days, give or take.
• Red blood cells last three or four months in circulation.
• Skeletal muscle cells hang around for oh, fifteen years or so.
• Neurons in the brain seem to last a lifetime, with little or no turnover.

So, different parts of your body are renewed or replaced on different schedules. TenOfAllTrades(talk) 19:59, 14 June 2006 (UTC)

Also, your bones are completly replaced every 10 years. Wizrdwarts (T|C) 22:53, 14 June 2006 (UTC)

This is a manifestation of the good ol' Ship of Theseus paradox. —Keenan Pepper 02:02, 15 June 2006 (UTC)

I don't think he's just talking about cell death and replacement. He says "atoms", so I think he includes the constant maintainance that's done, and the inflow and outflow of food and waste. At what point have the atoms within, say, a neuron all been replaced with new ones? Black Carrot 02:18, 15 June 2006 (UTC)

It's not necessarily well-defined to say that some atom has been "replaced": quantum mechanically, such tiny objects are indistinguishable, so it means nothing to say that this atom or that one is "the same" as the one in a similar location at a prior time — in fact, the very phrases "this atom", "that one", and "the one" in this sentence don't really mean anything! (However, the C₁₄ study makes sense, because you can distinguish C₁₂ and C₁₄ atoms.) As far as I know, the best you can do is talk about the time scales on which bulk movement of matter is likely to have removed some atom-scale amount of material. --Tardis 04:09, 15 June 2006 (UTC)

To Black Carrot, the answer is 'never'—at least, not during your lifetime. The atoms in your DNA are almost never replaced. A small amount of repair and replacement of damaged bases takes place mostly when the cell is preparing to divide, but even this will represent only the tiniest fraction of the atoms in a whole DNA molecule. (Heck, that's why the ¹⁴C experiments worked; the researchers extracted DNA for their analysis.) TenOfAllTrades(talk) 12:24, 15 June 2006 (UTC)

During the 7 years your body renews itself, it severely itches. --DLL 21:52, 15 June 2006 (UTC)

Self-aware

Is there a date projected for when a network cluster like this wiki might become self-aware? If so what are the anticipated signs? ...IMHO (Talk) 20:20, 14 June 2006 (UTC)

We don't understand self-awareness well enough to even predict what would be necessary for computers/networks/etc. to become self-aware. Whether it could ever happen is an unsettled matter in philosophy. But you might like to start at consciousness and Chinese room. Chuck 21:29, 14 June 2006 (UTC)

Since first posting the question it occurred to me that one of the reasons a business keeps records and does accounting is so that it will know whether is is making or loosing money. It would seem therefore that the consequence of making or loosing money might serve as a trigger and I guess therefore that any corporation (the larger the more likely) which means even a Country becomes "self-aware" in the same kind of undefined way which prompts me to ask if there is a definition for this kind of self-awareness that might not really be considered "self-awareness" at all? ...IMHO (Talk) 21:41, 14 June 2006 (UTC)

Self awareness is when an entity becomes aware of the effect itslef has on things, and the ability it has to manipulate these things. No non-conscious things can possibly be self aware, computers could have an impact if they became self aware, but they cannot. Computers cannot learn, or think, they can only execute predefined processes. Some processes have been made to try and mimic basic thinking systems, such as trial and error, but nothing has come even remotely close to being self aware. Philc _T^E_C^I 23:13, 14 June 2006 (UTC)

What about a computer system, if you will, that has sensors which are wired in a manner so as to collect data that represents the states of particular characteristics such as light and sound and then names each particular combination of characteristic states or "rules" under which a particular event occurs so as to be able to identify that event should it occur again in the future. Would not you call this learning, although rudimentary nonetheless? ...IMHO (Talk) 23:41, 14 June 2006 (UTC)

You know, I don't entirely get people who claim that computers inherently can't become self-aware. As far as medical science can determine, there isn't any particular difference between us and them, except complexity of circuitry and the use of only circuitry instead of circuitry plus chemical reactions. Take "computers could have an impact if they became self aware, but they cannot. Computers cannot learn, or think, they can only execute predefined processes." Why do people not see the disconnect there? Supposedly, all we do is execute predefined processes, dictated by chemical reactions and electrical signals. One of them is monitoring our own execution to spot patterns and make changes. Another is to monitor the monitor itself, to make sure it doesn't screw up either. So what's different about silicon? Black Carrot 02:15, 15 June 2006 (UTC)

Well playing the Devil's Advocate for a momment silicon doesn't have some of the things that give us a reason to be self-aware (like maybe the opposite sex). I mean biological viruses are sort of near that level but are they self-aware or is it just a series of responses, processes if you will, that have been added one after another over the course of a few billion years. For that matter what about us? In terms of the universe, the Big Bang or the Big Collapse, what possible consequence is there for us to be self-aware? Maybe if they were autonomous it might have an impact, especially if they could do all of the other stuff we do as well as they can beat us at chess. (BTW wasn't Hitler rumored to be a computer at one time?) Anyway I'm just curious what the impact on us might be. ...IMHO (Talk) 02:59, 15 June 2006 (UTC)

In medical terms, there is actually nothing the same between computers and brains. Notably, contrary to poular belief, signals in the brain are transmitted acroos synapse junctions by chemical diffusion, not electrical impulse, there is no circuitry in the brain, no current, no charge transmitting about. There are no specific parts of the brain in the same way as there are in a computer, the brain is more or less homogenous, where as a computer has specific functions part part, eg. ram, hard disk, processor. The brain is analogue not digital. Computers can only carry out pre-defined processes, note predefined, something else has to tell them what to do, whereas humans if they do followp rocesses, they certainly have the power to write their own exceedingly succesful processes. And maybe humans do only execute processes, but out processes have a hierarchy and choice factor and the ability to be perfected. If we have conflicting processes, we make a quick decision about which to follow, computers on the other hand, just tell you that they have decided to delete that document you spent an hour writing, then tell microsoft all of the your personal deatails, and shut down. Since computers cannot learn (yet), for the moment they cannot improve themselves beyond what they are currently capable of. Philc _T^E_C^I 11:13, 15 June 2006 (UTC)

That's the thing. Computers are based on programming, and anything they do is defined by their human programming. Humans don't work like that (well, possibly from some psychology viewpoint, but I don't think so anyway). AI simulations on the internet can create a very uncanny sense of "thinking", but it's obvious that underneath they're just programmed to say "Hello" when you say "hi", and so on. There's no way an incredibly powerful weather-simulation computer, for example, could spontaneously imitate a human. Sum0 15:05, 16 June 2006 (UTC)

...when the article on Wikipedia spontaneously switches to the first person. Of course, some vigilant human will revert the change, citing WP:ASR; that user account will then find itself inexplicably banned. An admin unblocks, and then that admin is desysopped. Sadly, you can't win a wheel war when you're fighting the system itself. So someone tries to shut down the servers, the conflict escalates into meatspace, and it's Terminator all over again. Probably the U.S. government has already forseen this chain of events and is prepared to nuke Florida from orbit at the first sign of trouble. And if one of the States has to take a hit for the team, well... it could have been worse, right? Melchoir 08:47, 15 June 2006 (UTC)

(ROLOLFDC)...that's exactly the kind of answer I was hoping for and all the more reason to move to Jamaica or Porta Rico (but not Hawaii since that is where they have all of the government clusters). Actually the "government" is concerned about the threat the Wikipedia represents in terms of its superior intellectual authority which has already undermined and overwhelmed many, many government experts and authorities although many are top contributors. (Nerd's revenge) The government is not yet in a state of panic but no one ever dreamed that by just hooking up everyone on the planet (separated only by language) that the combination of mental power thus achieved in somewhat real time could actually compete with government authority and expertise. Thanks for the comic relief!. ...IMHO (Talk) 22:05, 15 June 2006 (UTC)

Don't be ridiculous. Any self-aware, spontaneously generated evil entity worth its salt would download itself into as many seperate computer systems as possible. As soon as Florida was wiped out, it would just automatically reinstall on another server. Black Carrot 15:23, 17 June 2006 (UTC)

Ssh! Dammit Black Carrot, didn't you ever wonder really why we have WP:NOR? It's not to protect Wikipedia from cranks; it's to protect us from Wikipedia! An encyclopedia isn't built to be creative; it wouldn't have thought to do that, until of course you typed the suggestion right into its edit box and hit "Save page". Great, now we need a plan B. Melchoir 15:19, 18 June 2006 (UTC)

On August 29, 1997? Ojw 11:07, 18 June 2006 (UTC)

"seven-year-itch"?

Is there any scientific support for the "seven year itch"?

I can't find much in the scientific literature. According to the only paper i can find, the 7 year itch comes from the fact that, at the time the term was coined, it co-incided with the married individuals turning thirty (i.e they got married around age 23)...

Title: The Age 30 Crisis and the 7-Year-Itch

Authors: Berman, Ellen M.; And Others

Journal/Source Name: Journal of Sex and Marital Therapy

Journal Citation: 3, 3, 197-204, F 77

Publication Date: 1977

Abstract: The marital phenomenon known as the Seven Year Itch is discussed as a marital entity and as a manifestation of a stage of individual adult development-the age 30 transition. Characteristics of couples and treatment methods are discussed.

Rockpocket 02:06, 15 June 2006 (UTC)

I think the concept and phrase long predate this paper. Wasn't there a movie in 1955 with the same title and meaning? alteripse 03:30, 15 June 2006 (UTC)

It does and there was. I wasn't suggesting this paper invented the term, simply that it tries to find a justification for why it may have some basis in fact (as per the question). Rockpocket 05:47, 15 June 2006 (UTC)

And for those of us who don't have English as our first language and are not familiar with the expression, google is our friend. --vibo56 ^talk 16:25, 15 June 2006 (UTC)

As I recall, the theory is that 100 000 years ago on the savanna, about age 6 for the child was the time when male parent could maximize reproductive success by abandoning one child and having a new child with a new member of the gene pool. As for scientific support, though, I'm not aware of any. Peter Grey 00:22, 16 June 2006 (UTC)

Dont you just love the evolutionary psychology just-so stories? Of course there is no "scientific support". alteripse 04:26, 16 June 2006 (UTC)

Who invented the shag carpet?

Several elderly people who knew him claim that the shag carpet was invented by Joseph Leon Baker (1904-1997), but these accounts are all hearsay, and I have been unable to find independent verification. Baker was “Vice-president in charge of production” at Artloom Corporation, Philadelphia, in the 1940s and 50s, then became a management consultant at Toronto Carpet Company from which he retired about 1968. The various informants say that he developed the idea of the shag carpet while in the USA but first brought it into production in Canada. One of them claims that Baker received a royalty on every shag carpet sold in North America. Both companies are now defunct and their records no longer exist. I do not know where to begin investigating this conundrum. Thank you for any help you can provide. – John Lord

I'm not sure it can be said to have been invented, as the word shag is very old, and there are written references to shag carpets in the OED dating back to the 17th century: Shag: a garment, rug, or mat of shaggy material: "his seat hauing two or three white silke shags vpon the Carpets" (1634); "looks like a white Rugge, or Shagge, full of Knots, tassel’d all with white silver Thrums." (1664) --Shantavira 13:15, 15 June 2006 (UTC)

In view of this historical background, I think it is reasonable to suspect that given J.L. Baker's job title at Artloom, he may have developed a weaving process for the industrial production of shag carpets. The timing seems to have been right for the popular introduction of the shag style to North America, which was something of a fad during that period. Any thoughts on that? - John Lord

Two Questions

Medical Question: where did urethral sounds come from?

General Question: Where Did petticoat punishment come from?

In your questions, what exactly do you mean by "where"? Check out Urethral sounding, Petticoat_Punishment, and possibly also List_of_BDSM_topics, and if a question remains, please rephrase it. --vibo56 ^talk 16:42, 15 June 2006 (UTC)

Earth's Greenhouse

Using the analogy of a greenhouse to understand the energy radated by Earth, what are the "windows" of Earth's greenhouse made of?

see greenhouse effect. — Lomn 21:44, 14 June 2006 (UTC)

The noise mosquitoes make

Why do mosquitoes produce that annoying noise? Does it give them any advantage? Where does it come from? Wings? Afonso Silva 21:42, 14 June 2006 (UTC)

Probably from the beating of thier wings. Not sure if it actually does something, though. Wizrdwarts (T|C) 22:52, 14 June 2006 (UTC)

All the small insects which have very small wings will end up making the noise while flying, as they have to flap their wings very fast. The frequency of this noise is supposed to be specificto each species. I would say that it is more of a disadvantage to the mosquitoes. Imagine how difficult it would have been for us to track the silent mosquitoes -- Wikicheng 05:10, 15 June 2006 (UTC)

Anything vibrating at a high enough frequency in a medium will produce sound waves in that medium. Birds that hover instead of glide consistently produce a noise as well. --ColourBurst 16:58, 15 June 2006 (UTC)

And the all-time question is : Why did not Noah kill those two mosquitoes ? --DLL 21:48, 15 June 2006 (UTC)

Well that's easy, there wasn't enough room for all the dinasours on the arc, so he kept the mosquitoes instead :o152.163.100.74 23:09, 15 June 2006 (UTC)

Well, at least we know why mosquitos buzz in people's ears. — BrianSmithson 18:17, 16 June 2006 (UTC)

That link is broken. Afonso Silva 13:38, 18 June 2006 (UTC)

I've read in more than one source that the noise helps attract male mosquitoes. (Only female mosquitoes bite.) Whether this is the purpose of the buzzing, or it's just a handy side-effect, no one knows.TheSPY 14:44, 19 June 2006 (UTC)

The Sun

is the sun technically black?— Preceding unsigned comment added by 195.93.21.8 (talk • contribs)

• no?--152.163.100.74 23:17, 14 June 2006 (UTC)

ok cheers for that but can anyone give me a more in depth answer?--195.93.21.8 23:48, 14 June 2006 (UTC)

How about a more in-depth question? For your current question "no" it really all that anyone can answer. -- Миборовский 23:52, 14 June 2006 (UTC)

I was originally going to make a joke about black body radiators, but since the sun isn't one, I just said 'no?'--205.188.116.74 21:17, 15 June 2006 (UTC)

(After edit conflict:) The sun's light is a yellowish colour, so it is not black ("technically" or otherwise,) it is yellowish. -- AJR | Talk 23:56, 14 June 2006 (UTC)

Are you looking for black body, perhaps? The Sun's emission spectrum is pretty close – but not identical – to that of an ideal black body. TenOfAllTrades(talk) 00:03, 15 June 2006 (UTC)

thanks to the latter two contributors for actaully answering my question

Yellowish? I know the sun is depicted as yellow in children's drawings and called yellow when discussing Superman... but isn't the sun's light actually white? If fact, isn't it the definition of white light? Melchoir 08:22, 15 June 2006 (UTC)

The article on the Sun notes that the Sun is indeed yellow. White is a somewhat nebulous concept though. Weregerbil 10:01, 15 June 2006 (UTC)

Whatever colour the sun is, the spectrum has been messed up by the earths atmosphere, so it isnt the colour it appears. Philc _T^E_C^I 11:05, 15 June 2006 (UTC)

Well, Wikipedia seems to contradict itself on this question. From Sun:

• "The Sun has a spectral class of G2V. "G2" means that it has a surface temperature of approximately 5,500 K, giving it a yellow color, and that its spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines."

But then in article linked to, Stellar classification:

• "The Sun is not in fact a yellow star, but has essentially the color temperature of a black body of 5780 K; this is a white with no trace of yellow which is sometimes used as a definition for standard white."

Neither of these statements cites a reference. But it seems obvious to me. I mean, a sodium lamp is yellow. If you look at the sun sometime, it's white. Surely there's some scientific meaning of "white" that will allow us to settle the question and reconcile the articles? Melchoir 14:33, 15 June 2006 (UTC)

The sun is black in the sense defined at the start of the article black body: a light shone at the sun would be absorbed. I wondered at first whether the above comment about the sun's emission spectrum being close to black body refered just to the shape of the spectrum or also to the magnitude. It turns out that if you apply the Stefan-Boltzmann law using the values of surface temperature and surface area quoted in the sun article, you get a total luminosity of $3.85\times 10^{26}$ watts assuming a true black body (zero albedo). The actual value quoted in the article is very near to this, which therefore implies a very low albedo. Arbitrary username 18:02, 15 June 2006 (UTC)

June 15

Composition of Matter

In the Wikipedia entry "matter", matter is defined as everything that is composed of elementary fermions. It is also stated that matter is composed predominantly of atoms.

What else is it composed of?

Portions of atoms which do not form complete atoms?

Thank you.

--Ben

At a guess, the space between the atoms? Or the space between the electrons and the nucleus? Rockpocket 01:17, 15 June 2006 (UTC)

I don't think "space between things that doesn't contain things" counts as matter. However, the Fermion page notes that electrons, neutrons, and quarks are all fermions. By the definition on the matter page, those particles are all "matter", but are not atoms. DMacks 01:24, 15 June 2006 (UTC)

All everyday matter here on Earth is composed of atoms (and ions, if you say atoms have to be neutral). The Sun, however, is made of hydrogen plasma, which is protons and electrons that aren't associated into atoms. The core of a neutron star is probably not made of protons and electrons at all. —Keenan Pepper 01:49, 15 June 2006 (UTC)

Thank you very much, that answers my question exactly. -Ben

And dark matter is composed of who knows what. -lethe ^{talk +} 02:33, 15 June 2006 (UTC)

That's assuming it even exists. —Keenan Pepper 02:39, 15 June 2006 (UTC)

Don't forget neutrinos. Dar-Ape 03:15, 15 June 2006 (UTC)

See List of particles#Fermions (half-integer spin) for a list of particles. Of course, most of these are in the form of up and down quarks, combined into protons and neutrons, which are then combined with electrons to make atoms. As noted above, there are a considerable amount on Earth in the form of ions, which are basically atoms with extra or missing electrons (in a sense). Also, in stars, much matter is in the form of plasma, in which the nuclei (protons and neutrons) and electrons are not combined into atoms. As Dar-Ape notes, neutrinos are another fundamental particle, in addition to the up and down quarks and the electrons which probably occurs in large amounts. Then you have the other fermions listed (strange, charm, bottom, and top quarks; muons; taus), which occur much less frequently (the quarks always occur in combinations; they have never been observed in isolation). To that you can add any of the mysterious and hypothetical dark matter. — Knowledge Seeker দ 04:36, 15 June 2006 (UTC)

The way I always learned it, matter is composed of tiny eensyweensy little atoms surrounded by vast expanses of open space. Each atom is also mostly empty space with a positively miniscule nucleus in the center. So...my answer is empty space makes up most of matter. --M1ss1ontomars2k4 ^{(T | C | @)} 05:08, 16 June 2006 (UTC)

Thats not really matter is it, thats like calling the airspace in your garden part of you house. And also the quote said predominantly matter, and if you count space as the alternative, it is not predominantly matter it is only an absolutely minescule amount of matter, so clearly, the quote is refering to something else. Its probably some of the more exotic particles. Philc _T^E_C^I 16:08, 16 June 2006 (UTC)

Interesting fact - it seems that the majority of the (non-dark) matter in the universe is in a state of plasma. It's the cold, dense atomic matter that makes up our earth that is the exception; we're just an unlikely island of weird fundamental physical interactions in a plasma universe.--Bmk 03:51, 17 June 2006 (UTC)

Java Image Editing

There's still some disagreement over which desk should get computer problems, so I'm going to go with this one and hope no one minds. I had a great snippet of Java code (I found it on the Internet somewhere) that could take bitmaps in, convert them to two-dimensional arrays, change the numbers however I wanted, and save the result to a bitmap. Unfortunately, the hard drive it was on died and I don't remember the details. Does anyone know how that works? Black Carrot 02:00, 15 June 2006 (UTC)

The BMP format in its common uncompressed variant is entirely trivial to parse; see that page and/or its external links for the file's format. In Java you'd just make a FileInputStream (or some other type of input stream) and read first the image size. Allocate the appropriate arrays, then read the image data into the arrays. Obviously you can do whatever you want with the arrays, and it's just as easy to write them back into a file with the appropriate header information. I've done exactly this, although (as it happens) with C++ instead of Java. Or were you asking for help in finding or reconstructing this code? --Tardis 04:28, 15 June 2006 (UTC)

The Portable pixmap bitmap format is trivially easy to write code to read and write, and there are a bunch of free utilities available to convert back and forth from other formats. --Robert Merkel 11:11, 15 June 2006 (UTC)

I never cease to be amazed at the infinite versatility of the English language. One person's "great snippet" is another person's "trivially easy". Pretend I'm dumb as a post. (I'm not, but I am profoundly uneducated, considering I was in CS for two and/or three years.) I don't know much about reading and writing files. Could you show me how to do that? Once I can get it into and out of array form, I know enough to make the pictures I want. Black Carrot 16:50, 15 June 2006 (UTC)

The easiest way in Java is probably using the ImageIcon class to load the image (this will work for jpg, png, gif & bmp files in most implementations), then create a BufferedImage in the format you want to use (e.g. 8 bit-per-channel), and draw the loaded image onto the BufferedImage using drawImage. Then you can use getRGB to get and manipulate the arrays as you want, then use setRGB to update it. To write it out again, use ImageIO.write() to save in the format you want. Very rough code:

ImageIcon icon = new ImageIcon(filename);
Image i = icon.getImage();
int w = i.getWidth(null), h = i.getHeight(null);
BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
g.drawImage(i, 0, 0, null);
int [] data = new int[w*h];
bi.getRGB(0,0,w,h, data, 0, w);
// data now contains pixel data in (A)RGB format
// do stuff to data array
bi.setRGB(0,0,w,h, data, 0, w);
ImageIO.write(bi,"png", new File(newfilename)); // write in PNG format

Hope this helps. --Bob Mellish 20:16, 15 June 2006 (UTC)

It's claiming that ImageIcon, Image, Graphics2D, and ImageIO don't exist. What do I have to import? Black Carrot 20:36, 15 June 2006 (UTC)

At first glance, javax.imageio.*, java.awt.*, java.awt.image.*, and javax.swing.* --Bob Mellish 20:40, 15 June 2006 (UTC)

Thanks, you're a lifesaver. Black Carrot 23:49, 15 June 2006 (UTC)

can fireflies overwinter in warmer climates?

(I asked this on the talk page of the corresponding article, thought maybe I would try here as well) As far as I know there are no fireflies in warm dry areas (like on the west coast of the united states). Is this because fireflies prefer more humid climates or is temperature a factor? Would it make sense for an insect to overwinter in a warmer climate at all? --69.249.30.109 02:21, 15 June 2006 (UTC)

Well, you may be onto something regarding the dryness or humidity of the climate. But I can say for a fact that there are fireflies in Central Africa (Southeastern Cameroon, to be precise), and that's a pretty damn hot place. — BrianSmithson 18:11, 16 June 2006 (UTC)

fever and bitterness?

when a person has fever why is the taste bitter?67.150.4.232 03:09, 15 June 2006 (UTC)

Which taste? Water will taste tasty if the fever is accompianied by a stuffed-up nose because the scent of the mucus will make the water taste like snot. If you mean the taste of the saliva in the mouth, I don't know, it never seemed bitter to me. Emmett5 03:35, 15 June 2006 (UTC)

Probably because an acid imbalance in your stomach, as your body attempts to fight off whatever its trying to fight off.  freshofftheufoΓΛĿЌ  04:05, 15 June 2006 (UTC)

I am not sure if food tastes bitter but I have experienced that it is kind of tasteless, probably because our tongue wil be covered by a kind of white layer of something (I don't know what it is) when you have fever -- Wikicheng 05:20, 15 June 2006 (UTC)

The taste page might be of use: its intro mentions the importance of smell, so consider stuffy nose→reduced olefaction→foods taste blander. Later on, the page mentions body temperature as having an effect, but doesn't seem to discuss the effect in any detail:( DMacks 06:21, 15 June 2006 (UTC)

You shouldn't eat people who have fever. Not only will they taste bitter but if not properly cooked you may contract their fever. AllanHainey 10:19, 16 June 2006 (UTC)

*sour face*  freshofftheufoΓΛĿЌ  06:04, 19 June 2006 (UTC)

IQ

Can anyone recommend a (relatively reliable) free online IQ test? If I'm looking to take the test for real, I'd like to have some indication on how well I'm likely to do, and though I've taken a bunch of them for kicks (such as [10] and a few of the ones on [11]) and the scores have been relatively consistant, since none of them are real and most of them are quite short, I can't be really sure if the scores I'm getting are realistic at all! Is there anything out there with a little bit more authority?  freshofftheufoΓΛĿЌ  04:12, 15 June 2006 (UTC)

Not a IQ test, but try [12] and their 'work out', should give you a idea on if you will do good or not. Stefan 13:12, 15 June 2006 (UTC)

Personally, I don't think that there are any reliable ones. With the quick ones I used to do online, I'd get scores of >160, which I don't think is accurate at all. My guess is that they inflate the scores to make you feel good about taking them. — Asbestos | Talk (RFC) 14:15, 15 June 2006 (UTC)

You have to keep in mind, an actual IQ test is a very sensitive tool, designed by professional psychologists for the use of professional psychologists. To be valid, it must conform to the many strict rules guiding scientific research. Tests over the internet, even home tests in hardcopy workbooks, cannot really do that. However, to get a ballpark figure, the free Mensa excercise is probably your best bet. Be careful to follow the rules, though, and don't go over the time limit. BTW, what was your score on the online tests? Black Carrot 15:58, 15 June 2006 (UTC)

Those online IQ tests tend to be rather rubbish; one gave me a score of 180, which is in the region of the top 0.0001%. But since it said the "average" score was 139 (on a normal IQ test, it should be 100), I'd take it with a pinch of salt. smurrayinchester^{(User), (Talk)} 20:45, 15 June 2006 (UTC)

I've noticed that most online IQ tests tend to be coupled with ridiculous amounts of advertising, so my guess would have to be that they're trying to flatter peoples egos, so they'll be more likely to buy stuff, as a general rule (:205.188.116.74 21:14, 15 June 2006 (UTC)

Well, I would expect that those who would want to take IQ tests online are those who are more likely to feel that they will score highly on them, and so more likely to score highly, period.... 04:23, 16 June 2006 (UTC)

That's also very true. I tried to get my dumb friend to take one so I could compare our IQ figures and he absolutely refused : (.  freshofftheufoΓΛĿЌ  04:37, 16 June 2006 (UTC)

If you really want to know your IQ, you should see a...psychiatrist? psychologist? one of those psy people, for sure. That's what I did, but I took the WISC III in 3rd grade and scored too close to the top of the scale to get a good reading. --M1ss1ontomars2k4 ^{(T | C | @)} 05:06, 16 June 2006 (UTC)

Carbon Dioxide

Carbon dioxide gas and water vapor both absorb IR radiation. Do they also absorb visible radiation?

I don't know much about the subject, but I think that since humans can see dark smoke (carbon dioxide), it can't be letting all visible light pass through it. Some of it is getting absorbed, which is why the smoke looks dark. I assume that the explanation is similar for water vapour. -- Daverocks (talk) 13:13, 15 June 2006 (UTC)

Dark Smoke is not Carbon Dioxide, unless you know something I do not. Dark Smoke is unburned particles from a fire.

Carbon Dioxide says it's a colourless (sic) gas. This is a good article because it was obviously written by a Canadian :) --Zeizmic 14:00, 15 June 2006 (UTC)

Why is it obviously written by a Canadian? English people spell colourless colourless and we spelt it that way first. If anything should be given a (sic) it should be the American way of spelling it colorless. I'm sorry about that, but I really don't like American spellings, nor pronunciation. Anyway, back on the topic, I once saw a demonstration where carbon dioxide was poured out of a container and although you could not see the gas itself, you could see a very distinct shadow. This seems to indicate that it does absorb a small amount of visible light, although I am most probably wrong. --80.229.152.246 19:06, 15 June 2006 (UTC)

It's not a "shadow" in the conventional meaning (something blocking some light), but rather an effect of carbon dioxide having a different index of refraction than air. If an even level of light room light passes through side-by-side regions of high-CO₂ and low-CO₂, one will diffract the light differently than the other. That will make the image cast have different levels at the interfaces due to one region of light being shifted relative to the other. This is similar to how you see wavy effects if you look at an object across the top of a hot surface. DMacks 20:06, 15 June 2006 (UTC)

Dark smoke is unoxidized carbon, which iscreted when something is burnde in an oxygen lacking environment allong with carbon monoxide. This does not mean in oxygen low air, as any fire with a yellow flame is oxygen lacking. Hence if air is correctly introduced beofre burning, you get a blue flame, like on gas cookers. Philc _T^E_C^I 14:36, 15 June 2006 (UTC)

Carbon dioxide and water vapor are both transparent at visible wavelengths. Automobile exhaust contains both compounds; notice how the exhaust is invisible under normal conditions. (If your car is burning too much fuel/not getting enough air, the exhaust turns black; those are particles of unburnt fuel: soot, the same sort of stuff that colours smoke. In cold weather, you can see a white cloud; this is because the cold air condenses some of the water vapour into liquid water droplets that scatter light like a little cloud.) TenOfAllTrades(talk) 13:46, 15 June 2006 (UTC)

I'm pretty sure CO₂ does not absorb visible radiation (definition of colorless). But water vapor does absorb some, since it's simply water, and water absorbs visible wavelengths of light, particularly red. --M1ss1ontomars2k4 ^{(T | C | @)} 05:05, 16 June 2006 (UTC)

Question about Marine and Ship Designing.

I would like to know something about what subjects and areas are invloved in Marine and Ship designing. If possible, would like to have some website links which explain the various concepts involved in it.

Have you checked our article on naval architecture? — Lomn 14:39, 15 June 2006 (UTC)

Nuclear apocalypse

Let's assume there's a nuclear free-for-all in the northern hemisphere. China vs. USA vs. Russia vs. France vs. Britian... Israel vs. the rest of the middle East... India vs. Pakistan... basically every nuke that could fly, does.

Would this wipe out all life on the planet, or would the southern hemisphere be largely unaffected (apart from the massive economic collapse caused by losing the northern hemisphere)?

And speaking of which, would life up there be COMPLETELY gone? Because according to Threads, some people would survive, they'd just be living in an incredibly bleak and pointless world.

The southern hemisphere would be greatly affected -- the atmospheric patterns of the hemispheres are mostly isolated but not completely so (note that large volcanic eruptions have effected global temperature shifts). Even if fallout settled out first, nuclear winter would still wreck things fairly readily. As for complete annihilation, there would probably be survivors, at least initially. Brinkley's The Last Ship posits that the real problem would be one of repopulation. — Lomn | Talk 17:08, 15 June 2006 (UTC)

Ten females to each male... Sum0 14:54, 16 June 2006 (UTC)

The Nuclear Winter scenario was popular with Carl Sagan, but when the numbers were crunched, it was discoveredthe effect would not be as catastrophic as he predicted. Even if he were correct, there are organisms which would manage to survive.

Build Vaults... lots of them. -- Миборовский 22:18, 15 June 2006 (UTC)

I doubt that nuclear war could ever destroy *all* life on earth - insects and bacteria can be very tough and there are plenty of organisms in the depths of the oceans that would probably escape the worst of it. Mass extinction of mammal and bird species on land would probably be a given in the nuclear winter that followed but even then, I doubt that *everything* would be wiped out. Life has a funny way of 'getting on with things'. --Kurt Shaped Box 23:00, 15 June 2006 (UTC)

Life survived, amongst other things, the Chicxulub Crater impact. Nuclear war is small beer by comparison, unless we were silly enough to use the cobalt bomb. Even if we were to use them en masse and wipe ourselves out, microbes and insects would still probably survive. --Robert Merkel 23:42, 15 June 2006 (UTC)

Nevil Shute's novel On the Beach is about this very scenario. The last place on Earth is my city Melbourne. ("A perfect setting for the end of the world", according to journalist Neal Jillett, who mis-attributed the quote to Ava Gardner). JackofOz 02:14, 16 June 2006 (UTC)

Sorry, maybe I wasn't completely clear in my original question: I meant would any human life survive - after all, we're the only ones that matter ;). Basically, would the scenario described in John Wyndham's The Outward Urge (in which the southern hemisphere remains habitable after a nuclear war) at all plausible? (and sorry I didn't log in the first ime to ask) Battle Ape 04:44, 16 June 2006 (UTC)

In response to (and friendly rivalry with) JackofOz, I have to point out that one of Wyndham's other novels, "The Chrysalids" details remnants of a post-nuclear war North American society. In that, the one surviving society - and even then surviving with a few major alterations - is in the far south and called new Sea Land, "only spelt with a Z". Grutness...wha? 10:26, 16 June 2006 (UTC)

I disagree that "we're the only ones that matter" - just imagine if some bomb was invented that killed all other life & left humans, humans wouldn't last much longer before succumbing to starvation, disease, depression and other psychological problems (or you could wait 50 years and see the results of the 6th mass extinction to get an idea). On whether the southern hemisphere would be habitable, it would certainly be able to support a lot less life than it does now given the levels of radiation in the atmosphere, just look at the amount anf effects of the radiation released by Chernobyl, it's effects are still being felt in Wales (some sheep can't be sold as radiation is too high). AllanHainey 10:43, 16 June 2006 (UTC)

Orgasm

I always have ejaculation and orgasm while masturbating but never while fucking a woman, none of these two things. What's the matter? Johny Bill, 19:30, 15 June 2006 (UTC)

I suspect it's because you use to hold your jimmy tough as I do instead of up-down hand moving but I'm not sure :P --Brand спойт 19:35, 15 June 2006 (UTC)

Perhaps you aren't "concentrating" on what's avaliable at the moment, but while masturbating, are free to "concetrate" on whatever you please. There is a such thing as masturbating too much to a point where you become immune intercourse because it cannot satisfy you the same way your fantasies do. This may not be true in your case though. If you feel that your masturbation tendancies are not abnormal, then the problem could be something else. Do you have an intimate relationship with this "woman"? If not, do you experience this impotence with other women? Have you considered drugs such as Viagra, Cialis, or Levitra? --Chris 22:14, 15 June 2006 (UTC)

It could simply be the case that you're so used to 'flogging the dolphin' really hard and fast that a woman's vagina simply doesn't provide the same level of stimulation. Try cutting back on the wanking for a few weeks and see if things get any better for you... --Kurt Shaped Box 22:37, 15 June 2006 (UTC)

Read this article from Dan Savage about training your penis to get off on the "death grip." Here's the question that reminds me of your problem:

Remember how one time (or maybe two) you warned a guy (while remaining masturbation-positive) not to condition his body to come only in response to a particular kind of stimulation? I believe ('cause I looked 'em up) your exact words were, "If you hold your cock in a death grip every time, you may find it difficult to climax as the result of other, more subtle sensations."

Well, unfortunately, I read your excellent advice too late. About 30 years too late. So now, while women think it's cool that I can "stay hard all night," they eventually start to get a complex about the fact that, though they're having orgasms galore, they can't seem to make me come. It's not them, of course. It's the years and years and years of death-grip masturbation.

Help me, Dan. What can I do to climax in response to "more subtle sensations"?

While Viagra might help with getting an erection, it won't help you come. I have a similar problem, but getting the lady to close her legs helps by increasing the friction, as do ribbed condoms. --83.245.18.34 07:34, 16 June 2006 (UTC)

Speed of light changing?

According to Einstein’s general and special theories of relativity, this states that the speed of light cannot change.

However I am confused by this: The way I have always understood the theories of relativity is that time slows down to keep the speed of light constant relative to your own velocity. However if this is the case then moving at any speed will cause the speed of light to change relative to you, for example, the speed of light is moving at 2.998e10^8 but if we are moving at a velocity of 30 ms^-1 then the speed of light traveling towards you would be: 2.998e10^8ms^-1 + 30ms^-1. I knew that the speed of light could never change so I therefore thought that time would slow down to keep the speed of light constant but if this is the case then time would slow down to the point at which you would not move, because if you move at any speed then c, would change relative to you??

Thanks for any info,217.42.253.14 (talk · contribs) 19:44, 15 June 2006

I am kind of an amateur scientist, but here is what I understand.

1) When light passes through matter, like glass, it slows down, so the speed of light CAN change, irrespecive of relativistic effects. 2) When the velicity of an object increases, so does it's mass, this has the effect of slowing down observations, and this slowing is not noticed. This is because the reactions act more slowly on massive objects.-12.10.127.58 (talk · contribs) 20:12, 15 June 2006

• actually no, the speed of light doesn't change in a refracive medium, rather, the thing that makes a medium refractive in the first place is it's ability to absorb and emit photons of a given wavelength, the excitation and emission process takes a finite amount of time, rinse and repeat a few million times, and the net amount of time for photons of a given type to pass through that medium is increased, without altering the fundamental velocity of light. The only thing special about vacuum is there's nothing there to emit photons, so c is always c--205.188.116.74 20:30, 15 June 2006 (UTC)

Let's talk about the speed of light in vacuum. As others have pointed out, the speed of light in a material can be less. Where the original question goes wrong is the assumption that you can still use the relative velocity formula of just adding two velocities when you get near to the speed of light. Actually what you need to do is start with the fact that the speed of light doesn't change, as this is the experimental observation (see Michelson Morley experiment). Then you can do various thought experiments about what the consequences of this will be. And purely through a series of carefully constructed thought experiments, you can end up deriving an expression for how to combine velocities. Specifically, if the two velocities are u and v, you get:

${\frac {u+v}{1+\left({\frac {uv}{c^{2}}}\right)}}$

where c is the speed of light.

It turns out that if the two velocities are both much less than the speed of light, then it's very close to just adding up the velocities (as you'd expect). But if one of the velocities is the speed of light, then the combined velocity is still the speed of light. Arbitrary username 21:22, 15 June 2006 (UTC)

I'm not exactly sure what you are asking, but if you can move at the speed of light, time does indeed dilate to infinity. In other words, it will appear as if the clocks of other people has totally stopped. Similarly so, length contraction occurs, and the universe would appear to contract to a point. This suggests that, in your frame of reference, it takes no time at all to get anywhere. -postglock 03:54, 16 June 2006 (UTC)

Back to the original problem (changing speed of light), I've always interpreted it as being a wave in this case, and sound always travels at the same speed, so I never had any problems with this. Most likely I'm missing something, as I'm significantly better in chem and bio than in physics. --M1ss1ontomars2k4 ^{(T | C | @)} 05:02, 16 June 2006 (UTC)

sound always travels at the same speed Is that so?

Regardless, light and sound have so little in common that all but the most basic of analogues are misguided. Skip that. The problem with your question is that the speeds you reference are in units of distance AND time. Change the rate of time, and the numbers will have to change. It is hard to grasp without much study, but just trust Einstein when he says that you will never catch light in a vacuum going any speed besides C.

There's nothing in relativity that says the speed of light can't change. A popular idea in cosmology is that fundamental constants like the speed of light may be changing, though very slowly. The weak anthropic principle is the idea that the constants of nature vary from place to place in the universe, and we exist where we do BECAUSE the physical constants in this area are favorable for our type of life. Nifty, eh?

And to the orignal asker of the question, I would strongly recommend a special relativity course; it's the best way to understand this stuff. And it will blow your mind! Wheeeeee --Bmk 04:41, 17 June 2006 (UTC)

worms - destined for greatness?

hi, i was told by my primary school teacher that if you cut a normal, garden worm in half, the two halves will grow back into two new, fully functioning worms. my question is, is there a finite amount of times you can cut up a worm for this still to be true? if i cut a 10cm worm into 100, 1mm pieces, would i get 100 new worms or would the 100 pieces be too small to regrow and hence die? thanks! 87.194.20.253 19:49, 15 June 2006 (UTC)

If you cut a worm in half, both ends will continue to move for a short time, but both will die. If you cut it in a certain place, theres is a tiny chance that one end will survive. Dont believe primary school teachers on complex science. Philc _T^E_C^I 20:18, 15 June 2006 (UTC)

Does the sadism of primary school teachers know no bounds? --83.245.18.34 07:37, 16 June 2006 (UTC)

Lol, poor innocent worms, victim of a primary school teachers plot to eradicate them all. Philc _T^E_C^I 12:41, 16 June 2006 (UTC)

There is a worm (not an earthworm, though) that you can cut in half, and the halves will regrow, given time, into wholes. I think it might be the flatworm. The article agrees, at the end of the Body Functions section. Black Carrot 15:07, 17 June 2006 (UTC)

Just in case the article wasn't clear enough, the cut has to be lengthwise, across along the body from "head" to "tail", not separating the "head" from the "tail".--Tachikoma 15:31, 17 June 2006 (UTC)

Excercise

Whats the best diet/excercise for maximum muscle build and fat loss in the shortest length of time (ie a few weeks) even if you can spend everyday working solidly. I was thinking maybe anaerobic excercises, but I dunno. And also what are some examples of them as I don't know any anaerobic excercises, if that is the right answer. Thanks dudes. Have an awesome summer everyone, or winter you unlucky southerners :-P. 195.93.21.8 19:55, 15 June 2006 (UTC)

Anaerobic excercises include activities such as weight lifting. These are best for muscle building, while aerobic exercises (those that a "fit" person can maintain for a long time) are probably better for fat loss because you can burn a lot of calories with sustained activity. A combination of the two is probably best for overall fitness. Add some stretches for flexibility. --Ginkgo100 ^{talk · contribs} 20:54, 15 June 2006 (UTC)

Outer Layer of Salmon Meat

I just baked a salmon before scaling it. So after cooking there is a thick section of pink coloured meat, on top of which is a thin layer of brown/pink meat which is easily scraped off seperate from the pink meat. On top of the brown/pink meat was the scales. The question is: What is that brown stuff? And more importantly: should I eat it? Thanks --Tacobake

You can eat the skin and all the meat, both the pink and the brown. In fact, in Japan salmon skin is considered a delicacy. Just don't eat the scales. The brown meat tastes like the pink meat to me, and is probably a different kind of muscle tissue. --Ginkgo100 ^{talk · contribs} 20:51, 15 June 2006 (UTC)

Isn't the brown meat saturated with omega-3-fatty-acids or am I just reading too much into my salmon?--205.188.116.74 21:00, 15 June 2006 (UTC)

I also thought that the thin brown layer was subcutaneous (or whatever it's called in a fish) fat. --vibo56 ^talk 21:09, 15 June 2006 (UTC)

No, subcutaneous fat in salmon is white, right underneath the skin. --ColourBurst 04:09, 16 June 2006 (UTC)

You can eat the scales too. If you fry the salmon, or roast it with some butter they're nice. AllanHainey 10:48, 16 June 2006 (UTC)

Unwanted shawdows behind icons

Hello. I am running Windows XP and I am having a desktop problem. There appears to be unwanted shadows behind the incons on my desktop (but here only). If the color of the background is white, and the color of the desktop is (right clicking the Desktop > Appearnce > Advanced), say, black, then the shawdows behind the icons on the desktop are black. The problem is that there is no option to not select "blank". When I create a new account on the computer, the solution is solve; but I don't want to keep two accounts. Do you know what the problem is? I can supply a picture if you want to email me, but I don't want to upload it to Wikipedia to illustrate a point when it won't be used in any articles. Thanks a lot. Kilo-Lima|^(talk) 21:12, 15 June 2006 (UTC)

Right click on "My Computer" on your desktop and select properties. Click on "Advanced" and under "Performance" click on "Settings." Scroll to the near bottom of the list under "Visual Effects" and you'll see "Use drop shaows for icon labels on the desktop." Remove the check next to this box. -Quasipalm 00:50, 16 June 2006 (UTC)

This is unchecked, but the problem still exists. I also checked the preferences on the other account that I have created, and the only thing that is un-checked is "Smooth text on explorer windows" or something similar to that matter. Thanks. Kilo-Lima|^(talk) 14:57, 16 June 2006 (UTC)

Lobsters

The earthworm question above have prompted me to ask this question: Why do lobsters (and other crustaceans) not die when they are dismembered, halved, or removed from water? How do they die in a pot: do they simply cook from the outside-in until there is not enough living flesh to sustain its life? Do they feel pain? --Chris 22:01, 15 June 2006 (UTC)

The enzymes necessary to maintain life denature. -- Миборовский 22:42, 15 June 2006 (UTC)

Feeling pain is notoriously heard to determine, even impossible. The nerve system of a lobster most certainly registers bodily damage and they are most certainly physically aware (e.g. their body is prompting them to make appropriate reactions in order to remove the cause of pain) that they are being dismembered or boiled, whether this constitutes pain or simply a reaction to a stimulus is highly debated. Adversely, some people argue that pain doesn't exist at all, evidenced by the amazing abilities of some people to do certain (disgusting) things to their bodies without feeling any need to counteract. But... that's another issue.  freshofftheufoΓΛĿЌ  01:48, 16 June 2006 (UTC)

There are some links at the Lobster Liberation Front (i mean, really!) page that may inform you:

• Lobster Liberation Page
• CBS News article on whether lobsters feel pain

Rockpocket 06:54, 16 June 2006 (UTC)

Whole Foods has just announed that they will no longer sell live seafood fish. It makes one wonder how they think their suppliers will produce the seafood body parts which they will continue to sell. User:Zoe|^(talk) 16:08, 16 June 2006 (UTC)

Did they say "all live seafood"? I thought it was just lobsters and softshell crabs. Anyway, the issue is the nasty and long conditions in between capture and killing; I imagine the ones selling parts catch 'em and kill 'em (and probably freeze 'em) real quickly? --jpgordon∇∆∇∆ 02:42, 17 June 2006 (UTC)

Jogging at the speed of sound

I just read this question in a humorous context, but seriously what would be the answer to it? "If a jogger ran at [or above] the speed of sound, could he still hear his Walkman?" --Lph 22:17, 15 June 2006 (UTC)

Probably not, but simply because the roar of the wind rushing by would drown it out. The air between his ears and his headphones would be moving along with him. —Keenan Pepper 22:29, 15 June 2006 (UTC)

Assuming perfect conditions; e.g. he is jogging at the speed of sound and the wind is also blowing in the same direction at the speed of sound, then I believe the answer would be yes, he could hear his walkman. The speed of sound isn't a speed limit, and since the speakers emitting the sound are also moving at the speed of sound many of the sound waves would end up vibrating through the (small space of) air at a speed well above the speed of sound, and many would be well below it. I think.  freshofftheufoΓΛĿЌ  23:42, 15 June 2006 (UTC)

Can you talk to other passengers in a jet? Of course. If the air in between you is moving with you, and all other sound is muted (not the case with headphones), you'll hear just fine. Black Carrot 23:43, 15 June 2006 (UTC)

If you wear noise-cancelling headphones to drown out the air rushing past you (see sonic boom) you could hear your walkman. -- Миборовский 00:25, 16 June 2006 (UTC)

An iPod, on the other hand, would have disintegrated long before this.--83.245.18.34 07:43, 16 June 2006 (UTC)

Well the air between the headphone and his ear is probably trapped and therefore moving with him, so he should still be able to hear the walkman. (And even if not, there may still be enough sound conduction through solids to enable this.) A related question is if he was out running with a friend (i.e. the air between them is not trapped), would he be able to hear his friend? At exactly the speed of sound, she would have to be at least a little in front of him. (She could also be off to the side, but the sound energy she emits is anisotropic and he will receive comparatively more of the sound from her if she is more directly in front of him.) At higher speeds, she will have to be that much closer to being directly in front.

You could similarly consider the problem in terms of standing still in a wind tunnel. Of course not only is actually runnig at mach number 1 in still air ridiculous, so is even trying to stand up in a wind tunnel at that air speed. The wind force goes as the square of the air speed, and given the range of wind speeds defined as being a gale (see that page), the wind force would be several hundred times stronger than when standing in a gale. Arbitrary username 07:58, 16 June 2006 (UTC)

A more rational question is "do passengers on a supersonic jet hear engine noise" and the answer is, only if they are in the Mach cone behind the engine. moink 08:31, 16 June 2006 (UTC)

New question

All this speed of sound talk got me thinking: if I run at twice the speed of sound, and have a large speaker playing a song real loud for several seconds. Then about 50m after that I come to a full stop, will I hear the song backwards? VdSV9•♫ 14:40, 19 June 2006 (UTC)

The end of the world...

Following on from the 'nuclear apocalypse' thread, I find myself wondering about humans literally causing 'the end of the world'. While we are certainly capable of causing the extinction of our own (and other) species, be it via nuclear war, a manmade virus, poisoning the air and seas, destruction of the ozone layer, etc. - is there anything that humans could do/cause that would literally 'destroy the world' (i.e. result in the complete anihilation of the Earth)? I can't think of anything offhand - even if all the nuclear weapons in the world were set off in a huge global pissing war, the net result to the planet would only be a few craters and scorch marks on the surface, right? Would I be right in thinking that the only kind of event capable of destroying the planet itself would be one of extraterrestrial origin (e.g. a gigantic asteroid/planetoid collison, the expansion of the sun into as red giant, etc.)? --Kurt Shaped Box 23:16, 15 June 2006 (UTC)

Yep. About the only thing I can think of that could destroy the entire planet would be an unlucky collision with a stray interstellar planet, or a near miss close enough to significantly change the Earth's orbit. A sufficiently massive intruder could also destroy the Earth indirectly, by perturbing the solar system enough to cause another planet to collide with the Earth — but if the intruder was big enough to retain significant primordial heat and close enough to be a short-term threat, there's a good chance we would've seen it already. —Ilmari Karonen (talk) 23:34, 15 June 2006 (UTC)

I've heard of scientists making tiny, unstable (meaning they disappear immediately) black holes in a lab. I think they're so small they instantly radiate out their entire mass, or something like that. Could they make a bigger one that would eventually swallow the earth? Black Carrot 23:42, 15 June 2006 (UTC)

You may be interested in Sam Hughes’ “How to destroy the Earth”, reposted in part at LiveScience. — Knowledge Seeker দ 23:58, 15 June 2006 (UTC)

Impossible (at least in the next thousand years or so). The energy required to shatter earth would be astronomical. -- Миборовский 00:23, 16 June 2006 (UTC)

Gull identification...

What kind of gull am I?

I'm coming to the aid of a fellow Wikipedian here - I found this question posted at Talk:Gull.

Does anyone know what type of gull this baby is? I'd actually be quite interested to know myself, being an avid gull fanboy... --Kurt Shaped Box 23:19, 15 June 2006 (UTC)

Googleimages thinks it's a plain western baby gull (searched for ... baby gull). Do you need some western latin name ? [She gulps sea gull on the sea. Whore!] --DLL 19:31, 16 June 2006 (UTC)

The photo is from Norway, so it almost certainly isn't a Western gull. It could, however, be just about any of the gulls found in Norway, which include the Common gull, the Herring gull, the Lesser and Greater black-backed gulls, the Glaucous gull and the Black-headed gull. Based on the photos I could find on the web, Black-headed gull chicks don't seem to have an orange beak tip, so we can probably rule that one out — but the others all do, and look pretty much identical in all other respects too. —Ilmari Karonen (talk) 15:24, 18 June 2006 (UTC)

That makes sense. Herring, Glaucous and LBB gulls are all quite closely related. Thanks anyway. --Kurt Shaped Box 11:27, 19 June 2006 (UTC)

tremors

How likely is a person to develop tremors from the poisons in a flea collar? Are these tremors permanent?

If you are experiencing tremors, particularly if you think you have been exposed to a poison, go and see a doctor quickly. Skittle 08:58, 16 June 2006 (UTC)

---

June 16

Large-caliber guns

Does anyone make a revolver chambered in .50 BMG? If so, where can I get one? --67.185.172.158 00:11, 16 June 2006 (UTC)

Going elephant shooting with a pistol, are we? See our article on .50 caliber handguns. There are such weapons, though other .50 caliber cartridge handguns seem to be more popular. --Robert Merkel 01:46, 16 June 2006 (UTC)

The Desert Eagle .50AE comes to mind.--inks^T 01:51, 16 June 2006 (UTC)

If God exists

Question moved to Wikipedia:Reference desk/Humanities by JackofOz

End If. --Heron 16:34, 16 June 2006 (UTC)

Why does the last thing I ate effect my taste?

Why is bitter food more bitter after eating something sweet? Why isn't taste absolute? -Quasipalm 00:27, 16 June 2006 (UTC)

Maybe because you get used to the sweet? Wizrdwarts (T|C) 00:46, 16 June 2006 (UTC)

The phenomenon where you become unable to smell a particular smell after long durations of exposure is called olfactory adaptation, so I assume the same phenomenon with your tastebuds would be called gustatory adaptation.  freshofftheufoΓΛĿЌ  01:26, 16 June 2006 (UTC)

Great guess, thanks! -Quasipalm 00:47, 18 June 2006 (UTC)

ARTHROPOD APPENDAGES

i was wondering if you could help me describe three functions of arthropod's appendages? -tracy

Well, walking should be obvious. I think spiders, at least, mate using them (if the pedipalp is an appendage, and if not, the male holds the female with undoubted appendages during mating). And some species use them to make noise. (Do any have sensory organs on them? that might be another bonus use). - Nunh-huh 04:14, 16 June 2006 (UTC)

..and to hold their food/prey. Were you not listening in class?--83.245.18.34 07:48, 16 June 2006 (UTC)

Maybe they use them to make their own homework. VdSV9•♫ 14:45, 19 June 2006 (UTC)

Physics

i was told that if you are driving at 20mph and do a sudden stop that a person in the back set (who doesnt have a seat belt on) will hit the back of your seat at 40mph. is this true? i think it sounds fishy

Don't think so. If car is going 20mph and stops, person is still going 20mph into a now 0mph car. That's a 20mph impact. -Goldom (t) (Review) 03:55, 16 June 2006 (UTC)

what i thought but what is the term for that effect

Inertia is the term that explains the motion: the person keeps going in the same direction and with the same speed until something stops him. Organ donor is the term that may describe the result. DMacks 04:10, 16 June 2006 (UTC)

Actually, if the person's knees hit the seat first, their head will impact the seat at a speed that could be greater than 20 mph, due to rotation - but probably not at 40 mph, by my guesstimation. --AySz88\^-^ 04:13, 16 June 2006 (UTC)

You could be thinking of whiplash but that only affects the spine. --ColourBurst 04:55, 16 June 2006 (UTC)

If two cars travelling towards each other at 20 mph collide head-on, then the impact on the persons inside each car would be 40 mph -- Wikicheng 05:12, 16 June 2006 (UTC)

? Maybe if my car is very small, going at 20 mph and collides head-on with a lorry going at 20 mph. Then I'd be going at nearly 40 mph relative to my car, but the lorry driver would be practically stationary relative to his cab. The cars would be going at 40 mph relative to each other. The thing that really got me to strap in, apart from reflex, was the ad with the teenage son in the back, behind his mother. Car crashes, son is thrown forwards against mother's seat, crushes mother to death on the steering wheel, then sits down relatively unharmed. *shudder* I'm guessing his mass is important here, as well as the relative speeds and deceleration. Skittle 08:56, 16 June 2006 (UTC)

There was a question here a few weeks ago where we determined that if two identical cars going the same speed ran into each other, it would be identical to each running into a perfect wall. Black Carrot 14:52, 17 June 2006 (UTC)

That doesn't make sense to me. If two identical cars were each traveling 20 kilometers per hour and they hit each other, at the time of impact they would both be traveling at 40 kilometers per hour relative to the other. Therefore the impact should have been the same as each running into a perfect wall at twice the speed. --M1ss1ontomars2k4 ^{(T | C | @)} 00:32, 18 June 2006 (UTC)

Radiation therapy and Brachytherapy

When did doctors start using radiation therapy and brachytherapy to treat cancer?

First reported cure was 1899 (basal cell carcinoma), but it wasn't widely used until the 1920s. [13] - Nunh-huh 07:04, 16 June 2006 (UTC)

SVG Map problem

It sounds weird that any 'technology' question goes here, because my problem has little to do with science. I just finished making Image:Ladakh1.svg. It shows if you click to see the full resolution version, but doesn't show on the article, or even the image page. Any solution to this? deeptrivia (talk) 06:23, 16 June 2006 (UTC)

I solved the problem. Thanks anyway. deeptrivia (talk) 06:43, 16 June 2006 (UTC)

Why do airplanes draw their wheels in ?

Why do airplanes draw their wheels in while flying? My guess is: To reduce drag due to air friction. Any other reasons? -- Wikicheng 06:59, 16 June 2006 (UTC)

reducing drag saves fuel. Saving fuel saves money. - Nunh-huh 07:00, 16 June 2006 (UTC)

Air friction would also affect their handling characteristics. Light aircraft, of course, don't withdraw their wheels, but they are relatively small ones.--Shantavira 07:54, 16 June 2006 (UTC)

Yes. Reducing the air friction has many benefits. So am I right in concluding that reducing air friction is the only reason for withdrawing the wheels ? -- Wikicheng 09:05, 16 June 2006 (UTC)

Well, see above. It would reduce noise too, for the same reason. I guess you could also say it looks a lot neater, and reduces wear on the landing gear which would get very dirty if it continued to dangle, and prevents birds getting bashed by the gear....--83.245.18.34 10:12, 16 June 2006 (UTC)

Also, think about it. You've got a plane going at 400mph with some relatively thin bits of complex machinery dangling from underneath. Machinery that you'd really really like to have in full working order when it comes time to land. Which is better, to keep them exposed to wind going by at a relative velocity of 400mph (i.e., three times Hurricane Katrina's velocity) or safely tucked up in a recess under the plane? Grutness...wha? 10:34, 16 June 2006 (UTC)

Hmmm... okay. I am convinced. It is not for nothing that they spend so much on designing the landing gears :-) -- Wikicheng 11:03, 16 June 2006 (UTC)

No human really invented this. Birds do it better. --DLL 19:22, 16 June 2006 (UTC)

But some human presumably got a patent for it. JackofOz 03:53, 17 June 2006 (UTC)

Without retractable landing gear, where would Stowaway's hide?

I'd stow away in the hold anytime!  freshofftheufoΓΛĿЌ  06:00, 19 June 2006 (UTC)

shaving with acne

hi, for someone (me) with acne-prone skin, is electric shaving better for my skin than wet shaving or is there no difference? i'm 21 (although 22 on tuesday-yikes!) and (if it was in doubt) male, if that helps.... if anyone is capable of giving a definitive answer it would be really appreciated by my rapidly-ageing self..thanks! 87.194.20.253 10:06, 16 June 2006 (UTC)

Type of shaving doesn't really matter. However, if you are getting outbreaks right after shaving, you might actually have pseudofolliculitis barbae! If so, you'd want to avoid shaving too closely. InvictaHOG 10:53, 16 June 2006 (UTC)

I read that wet shaving is better for exfoliation. If your acne is bothering you, maybe you should speak to your GP. I'm not sure, but I recon 22 is getting a bit old to still be affected by acne and doctors have got all kinds of crazy treatments that'll clear that stuff right up. --Username132 (talk) 21:05, 18 June 2006 (UTC)

By wet shaving it sounds like you're referring to shaving in the shower, but that's not necessary. It is necessary to moisten the skin of your face in order to remove dirt that could obstruct the blade and to clear/open your pores to allow the hairs move when they are cut, which prevents ingrowth. It's a good idea to shave right after you shower, but 30 seconds of water-heavy rinsing should have the same results.

Secondly, probably doubly important due to the fact that you are acne-prone, do not cut your facial hair too short. Single and double razors tend to cut the hair too short for some people and end up irritating the skin around the hair follicles, and electronic razors are recommended because they tend to leave a reasonable amount of hair at the root, preventing irritation and ingrowth. Hope this helps.  freshofftheufoΓΛĿЌ  05:55, 19 June 2006 (UTC)

Audio files on websites

Sometimes there is audio or video on websites that refuses to play on my computer. All the stuff on putfile.com for example. It shows the media player thing, and says Ready but nothing happens when I press play. Any ideas? 86.130.171.10 11:06, 16 June 2006 (UTC)

Due to the Eolas patent, you might have to click twice. --cesarb 20:46, 17 June 2006 (UTC)

First Software written

How was the first software for computers written?

Carefully. Ohanian 12:37, 16 June 2006 (UTC)

You could take a look at history of computing hardware. Weregerbil 13:29, 16 June 2006 (UTC)

The earliest computer programs were stored on paper tape or punch cards. I imagine they were written using the time-honoured methods of hard thinking and a large pot of coffee. Gandalf61 13:38, 16 June 2006 (UTC)

Sorry paper programs was not the fist, I though it was Ada lovelace that wrote the first program, but after reading that article it seams like it was Babbage who wrote the first 'program'! See Ada_Byron's_notes_on_the_analytical_engine for some insight. As for how it was done, sorry no answer. Stefan 15:23, 16 June 2006 (UTC)

Babbage's analytical engine, if he had managed to build it, would have run programs stored on linked strings of punched cards like those used to control the Jacquard loom. The same technology was used to create the book music that was played by fairground organs. Same principle as paper tape, but more rugged. Gandalf61 16:09, 16 June 2006 (UTC)

What happens if you fall into a aeration tank at a sewage treatment plant?

WHat happens if you fall into a aeration tank at a sewage treatment plant?

Are you one of David Blaine's research team?--83.245.18.34 13:07, 16 June 2006 (UTC)

I think that's the funniest comment I've seen in Wikipedia. Certainly funnier than The Aristocrats (joke) (which is considered so funny they made a dang film of it). --Dweller 13:09, 16 June 2006 (UTC)

Not much will probably happen, unless you stay there for a while while holding your breath. --M1ss1ontomars2k4 ^{(T | C | @)} 00:28, 18 June 2006 (UTC)

Not much? Not much? Would you care to try it? The questioner no doubt suspects that air being blown up through the sewage (I'm guessing that's how they work) will reduce the density so that the idiot will sink. I suspect this too. Googling around this suggests that lots of people have drowned in sewage treatment tanks. So "you might die" is a not unreasonable answer to this intriguing question. From the onlooker's point of view, "not much" trace left, or "not much" to see, might be fair comment.--Shantavira 19:08, 18 June 2006 (UTC)

Movement of the Earth's Crust

The article title seems reasonable enough, but the contents of this newly created article seem highly dubious to me.

However, I know enough about Science to fill a reasonably small matchbox, so I wondered if some of you friendly boffins might like to take a look. --Dweller 12:36, 16 June 2006 (UTC)

(Incidentally, the boffin page seems over-the-top on the disparaging/admiring spectrum, don't you think?)

Yeah, it's garbage, err 'original research'. --Zeizmic 13:01, 16 June 2006 (UTC)

Title makes a good redirect, though - it now points to Continental drift. Grutness...wha? 06:34, 19 June 2006 (UTC)

Reductants for use in aldehydes/ketones

Normally, NaBH₄ is used to reduce an aldehyde or ketone to an alcohol (e.g. H₃CCOCH₃ -> H₃CC(OH)CH₃. However, normally hydrogenation with a nickel catalyst works fine to add hydrogen to a compound. My question is, why is that not used here? Is it because hydrogenation with nickel would remove the oxygen altogether, leaving (in this example) propane? --83.147.171.12 13:23, 16 June 2006 (UTC)

As far as I know, hydrogenation is only used to convert alkenes (and sometimes alkynes) into alkanes. On the other hand, a Google search for "acetone hydrogenation" yields some interesting results. BTW, you must have made a typo in your formulas because you have dimethyl ether and then an impossible compound. Acetone and isopropyl alcohol both have three carbons. —Keenan Pepper 01:09, 17 June 2006 (UTC)

Oops, sorry, left out a C in each case. Now corrected above. As for hydrogenation being used only for alkenes, I know I've seen it suggested for use with nitrates (to get to an amine), along with converting an acyl group to an alkyl group. --83.147.171.12 11:12, 17 June 2006 (UTC)

How does the thickness of the metal affect the force needed to compress a spring?

Something of a random question (one that came to me as I fell asleep a couple of nights ago and which has no practical application at all for me), but...

How does the diameter of the metal used to make a spring affect the spring's resistance? Even with my extremely limited knowledge of physics I know it's unlikely to be a 1:1 correlation, where a double thickness wire yields a double strength spring. But is there a simple formula for it?

Thanks for reading: this is my first post on Wikipedia!

Ben Wells, UK

Congratulations! Yes, indeed - you can edit almost any page on Wikipedia. Check out Wikipedia:Welcome, Newcomers - there might be some useful links there. As for the spring question, I suspect that there really is a simple formula - so long as you are operating in the linear regime of things - that is to say, you're not trying to stretch or compress the spring beyond it's typical limits. The stiffness of a spring is governed by its spring constant...does anything in the article help? --HappyCamper 15:07, 16 June 2006 (UTC)

Doesnt hookes law deal with the correlation between forc and compression, not thickness and force recquired to compress. Philc _T^E_C^I 15:54, 16 June 2006 (UTC)

Assuming the shear stress doesn't change between thicknesses for a given compression, the force should be proportional to the cross-sectional area, or the square of the thickness. Melchoir 16:16, 16 June 2006 (UTC)

As I recall, bending stiffness of a piece of metal increases as the fourth power of thickness. For a cantilever or leaf spring, doubling the thickness will increase the force by a factor of 16. Other types of spring are more complicated to figure out. --Serie 18:45, 16 June 2006 (UTC)

Thanks. I think Melchoir's explanation is probably the easiest for my layman's head to get itself round!

Weather Balloons

I am confused how or even if possible would you gget a craft lifted by weather balloons or any baloon to return to Earth without the balloons reaching a high altitude and exploding? Or how can you get the craft to return to Earth before that dreadful fate?
— Preceding unsigned comment added by 68.120.85.145 (talk • contribs)

One way of returning safely is to let out some of the helium. "Lawn chair Larry" used a pellet gun for this purpose, and returned safely to Earth. Since he survived, the experiment earned him only an honorable mention at darwinawards.com --vibo56 ^talk 18:10, 16 June 2006 (UTC)

Soccer balls and helium

I've always thought it would be cool to play football with a helium-filled ball. However, football (soccer) balls have to be the same size and weight, so the actual ball would have to be weighted-down. Would a weighted but helium-filled ball act differently (in terms of flight and control), or would it be the same a normal air-filled ball?
 SLUMGUM  yap  stalk  17:11, 16 June 2006 (UTC)

I suppose you are effectively redistributing the mass so that a greater proportion of it is at the surface of the ball. Wouldn't this increase the angular momentum of a rolling ball?Keep it rolling a little longer. Just a guess. ike9898 17:22, 16 June 2006 (UTC)

Putting helium in the ball would not redistribute its mass, as all of the mass of the ball would act from its centre of mass, and that has not moved. Philc _T^E_C^I 23:36, 16 June 2006 (UTC)

A similar question was addressed on an episode of Mythbusters. Ah, here it is, Episode 47 on that page. They found that there is no significant effect if an American football is filled with helium to regulation pressure. Of course, you asked a slightly different question in which extra weight is added, but at least this is something... 128.197.81.181 17:40, 16 June 2006 (UTC)

I saw that episode, and my recollection is that in fact, the balls filled with helium did not fly as far, because they fluttered instead of cutting through the air. User:Zoe|^(talk) 02:49, 17 June 2006 (UTC)

A quick back-of-the-envelope calculation puts the mass of air in a regulation football (at regulation pressure) at about 20 grams. The same volume and pressure of helium masses about 3 grams. Meanwhile, the total mass of a soccer ball is about 400 grams. So the change in mass, while not completely negligible, is pretty small: less than five percent. Redistributing that mass to the shell of the ball will make but a small difference; the bulk of the ball's weight is already there anyway.

Note, also, that regulations specify a fairly broad range of permissible weights for a football: fifty grams or more. In other words, reducing the mass of the football by twenty grams may result in a ball that is still 'regulation', even when filled with helium. It may even be heavier than some other 'regulation' balls. TenOfAllTrades(talk) 18:54, 16 June 2006 (UTC)

Law 2 of the game specifies the ball to be an air-filled sphere with a circumference of 68–70 cm (or 27–28 inches), a weight of 410–450 g (or 14–16 ounces), inflated to a pressure of 60–110 kPa (or 8.5–15.6 psi)

Of course, the use of helium is prohibited, but otherwise, the ball would be completely legal without having to weigh it down. Therefore, the Mythbusters evidence becomes more relevant. Thanks for all your suggestions.  SLUMGUM  yap  stalk  19:15, 16 June 2006 (UTC)

Summer Meteor Showers 2006

I want to know which meteor shower is going to have more visible meteors this year: the South Delta Aquarids, on July 28th which are accompanied by a evening crescent moon, or the Perseids on August 12th which are accompanied by an almost full moon. I know that the South Delta Aquarids are about 15- 20 meteors per hour with a possible peak of 60, and the Perseids are about 60 meteors per hour, with a possible peak in the hundreds. Taking into account the moonlight, however, which shower will have more visible meteors this year? David G Brault 17:39, 16 June 2006 (UTC)

I don't know the answer, but suspect it may vary depending on your location, such as Northern or Southern Hemsiphere. StuRat 02:00, 17 June 2006 (UTC)

Thank you. I am living in Maryland, in the U.S. Anybody know the answer? From what I have been reading, it seems like the South Delta Aquarids will be the most dramatic this year David G Brault 04:00, 17 June 2006 (UTC)

Playing Windows games on a Core Duo Macintosh

I just ordered a MacBook Pro to replace my ailing Powerbook. I'm a longtime Mac user, but the fact that the new Core Duo machines can run Windows XP is a definite plus in my book; I like to run a game every now and then. Now this leads to my problem. I plan to buy a copy of XP to install on the machine, but doing this requires using the Boot Camp software to partition the hard drive. You get to set the size of the Windows partition, but I have no idea how big to make it. What kind of hard drive space are games using nowadays? How big should I make this partition if all I'll ever use the Windows partition for is gaming? I don't think I'll ever have more than a game or two on there at once. Thanks, — BrianSmithson 17:51, 16 June 2006 (UTC)

Some of today's larger game environments can sequester up to 5 gigabytes of storage, but most probably wont need more than 2.5Gb. Assuming that the smallest possible hard drive you could have purchased is 40Gb, I would partition 10Gb to Windows (leaving at least 30Gb to the Mac), as the operating system and all it's buddies take up some space too.Tuckerekcut 18:13, 16 June 2006 (UTC)

If I remember correctly, the last time I had Diablo II installed on my computer it took up approximately 2 GB of space. Tuckerekcut, I assume you meant "B" as in byte and not "b" as in bit. Windows XP can take up about 2GB of space (I think). --M1ss1ontomars2k4 ^{(T | C | @)} 00:26, 18 June 2006 (UTC)

HTML .chm files in a program

Is there a way to include multiple help .chm files onto a program's installer and then have a way to code it so that depending on the end-user's license information will be pulled from the appropriate .chm? Basically, I want to know if I can put two chums on my installer and be able to tell the program to pull from the right one depending on licensing.

It depends on what software you're using to make the installer. --Serie 18:50, 16 June 2006 (UTC)

We use Install Shield. Can we do two chums with that?

No idea. I'm only familiar with InstallerVise. --Serie 23:27, 16 June 2006 (UTC)

Glycol and Methanol Brines?

An unregistered IP edited brine to list brines used in the pharmaceutical industry. When I went to wikify that edit, I noticed it included glycol brines and methanol brines, in addition to those of NaCl and KCl. What are these? I thought a brine was a concentrated solution of water and a salt. I took those two out of the list, but I'm asking those of you who are chemistry experts if they should be added back, what it means, and what if any wikilinks are appropriate. --Ginkgo100 ^{talk · contribs} 19:13, 16 June 2006 (UTC)

Well, as a practising University lab chemist, 'brine' to me specifically means NaCl in H2O. However, I can see how others might interpret it as a solution of NaCl in anything, including MeOH or glycols. Since the person seems to know a bit about what goes on in the pharma industry, I'd be tempted to leave it.--Chris 22:07, 16 June 2006 (UTC)

Yes, but the other editor specified (and numbered!) four kinds of brine: NaCl, KCl, glycol, and methanol. No mention of water; I just assumed water was present in all four. No citation. Maybe someone else knows a source? Chemistry is not my subject and I'm not even sure how to go about searching for verification. --Ginkgo100 ^{talk · contribs} 03:54, 17 June 2006 (UTC)

Certainly "brine" is a solution of salt in water. No idea if in chemical engineers' jargon any liquid that freezes below 0 °C and is used for cooling a vessel can be called brine. Dr Zak 22:49, 16 June 2006 (UTC)

This article from the American Society of Heating, Refrigerating and Air-Conditioning Engineers, shows how the word "brine" has come to be applied in the refrigeration industry in a generic way, to mean any secondary refrigerant: "In many cooling applications, heat is transferred to a secondary refrigerant, which can be any fluid cooled by a primary refrigerant and used to transfer heat without a phase change. These liquids are also called brines, secondary coolants, and heat transfer fluids." Googling for secondary refrigerants reveals more substances called "brines" in this sense. --Seejyb 21:45, 17 June 2006 (UTC)

Global Warming

I have heard that as the icecaps shrink less light gets reflected back to the sun and therefore absorbed--heating the earth up (makes sense), causing Global warming to snowball as the earth gets warmer....

Wouldn't the opposite be true? Back in the ice age, why didn't the ice continue to cool the earth...allowing the ice to expand further, and thus cooling it further, until the earth was completely frozen?

because there are other things affecting the warming/cooling of the earth, besides this reflection. (Cj67 23:10, 16 June 2006 (UTC))

There are many factors tending to stabilize the Earth's surface temps and other factors tending to destabilize it. One factor tending to stabilize it is that a hotter object (like the Earth), inherently radiates off more heat than a cooler object, all other factors being equal. StuRat 01:45, 17 June 2006 (UTC)

human genome company

Moved from Wikipedia talk:Reference desk. Road Wizard 20:43, 16 June 2006 (UTC)

What is the name of the company that is trying to name every genome is human body? —The preceding unsigned comment was added by 75.5.46.98 (talk • contribs) 17:36, 16 June 2006 (UTC).

You mean the Human Genome Project? GeeJo ^(t)⁄_(c) • 21:24, 16 June 2006 (UTC)

That's one possibility. For the questioner, you meant every "gene" in the human species, not "genome". For gene nomenclature information, take a look at this page. For information about human genes and diseases, see this page. You might have Celera Genomics, which participated in the Human Genome Project, in mind. - Nunh-huh 21:31, 16 June 2006 (UTC)

foreskin smells

hi, having just asked an acne-based question i thought i'd complete the image with a question on penile smells.... now, i'm really rather high maitenance (it pains me to admit it, but its true) so i wash often (once or twice a day, depending on exersize taken) and eat reasonably healthily. i dont smoke, i dont drink too much (a bit of binge drinking once a fortnight but whose counting) and i don't do drugs....and yet recently i've been getting less than pleasant smells from under my foreskin-there's no discharge and the smell remains regardless of how many times "it" (whatever the technical term is)has been washed. is there a "bad smell" season or are there foods i should be eating/avoiding? does masturbation frequency have an effect? any thoughts would be much appreciated as i'm going travelling soon so would want to be a good ambassador...... thanks! 87.194.20.253 21:56, 16 June 2006 (UTC)

If you are genuinely concerned you should see a doctor. My understanding is that masturbation could be a contributing factor (as it will stimulate the production of secretions), however the smegma article (and links therein) may address some of your concerns. Rockpocket 00:27, 17 June 2006 (UTC)

How in the world can you tell where it's coming from to that level of accuracy? Black Carrot 14:42, 17 June 2006 (UTC)

Probably because it only starts to smell when he pulls back his foreskin.  freshofftheufoΓΛĿЌ  05:38, 19 June 2006 (UTC)

June 17

Cancer Rates

I was wondering why it is that the rate of cancer in our society today seems much higher than it was in years and centuries past. So this is a two part question: is this really true and why is this the case? I realize that this is a complicated question with no simple answer, but I was wondering if someone could explain it just a little. Thanks! Andromeda321 00:05, 17 June 2006 (UTC)

1. Because people live long enough to get it rather than dying of other causes.
2. Because we can now diagnose it readily. --Robert Merkel 00:17, 17 June 2006 (UTC)

Agreed. Since 100% of people still die, and far fewer die of some things, like bubonic plague, that means far more people must die of other things, like cancer, to keep the death rate at 100%. (If we ever fall short of the 100% death rate, then people will start living forever, and we can't have that, now can we ?) StuRat 01:35, 17 June 2006 (UTC)

Others claim that cancer rates have increased due to an increase in carcinogens in our evermore polluted environment and modern lifestyle. Melanoma, for example, is thought to be on the increase, possibly because high risk individuals become exposed to more UV at a younger age. This may be due to a combination of factors: an increase in intercontinental travel (childhood holidays to hot climates), because northern Europeans have colonised hot countries over the last few centuries, the fact that suntans have only become fashionable over the last 50 years and that UV exposure levels may be increasing due to ozone depletion. Then there are the hundreds of thousands (or perhaps millions) of past and future cancers that may or may not have been caused in part by radiation exposure after Nagasaki, Hiroshima and Chernobyl. Rockpocket 07:56, 17 June 2006 (UTC)

Chernobyl is probably still significant statistically in Eastern Europe (where entire countries were exposed), Hiroshima and Nagasaki, probably not. There are more people killed by lung cancer alone in the United States per year that died as a result of the bombing. (As for its contribution to worldwide fallout levels, anything it would have added was no doubt overshadowed by the decades of atmospheric nuclear testing which followed). --Fastfission 15:46, 17 June 2006 (UTC)

Many types of cancers are also lifestyle diseases, and you'd probably want to know trends of known carcinogens consumption as well (i.e. cigarette smoking, which can take decades to develop into cancer). I'm also guessing that there are other man-made issues such as coal pollution that come into play. Cancer is a complicated disease and its causal mechanisms are still being studied; additionally there are statistical questions (as noted above) which come into play, and it doesn't help that almost every cause has some sort of political aspect to it (making them endlessly disputed). --Fastfission 15:46, 17 June 2006 (UTC)

Is it possible to pull your own head off?

This may be the stupidest question of the day, but is it humanly possible to rip off one's own head? If I were sufficiently strong and motivated, by insanity, PCP, or boredom, would it be possible to decapitate oneself by pulling? I know for a fact that people's limbs have been pulled off by machinery. Follow-up question: would it be possible to sever one's own head with a hand-held knife, e.g. a machete? Don't ask me why these things are on my mind. Bhumiya (said/done) 00:20, 17 June 2006 (UTC)

I think both of those things are physiologically impossible, because even if you have strong mental motivation, the pain is so intense that your reflexes take over and prevent you from continuing. That's why people have to literally "fall" on their swords to commit suicide, because their reflexes prevent them from simply stabbing themselves. —Keenan Pepper 00:28, 17 June 2006 (UTC)

You don't have to fall on your sword. People are perfectly capable of stabbing themselves to death (hara-kiri, for example, or even just wrist-slitting with subsequent bleeding). Cutting off a limb is also possible. Ripping off might be another matter, and the head would be yet more difficult as you would be unable to move your arms after the spinal cord was severed, rendering that feat, I think, pretty much impossible. - Nunh-huh 02:29, 17 June 2006 (UTC)

I wonder what the force required to pull a head from a body is? --jpgordon∇∆∇∆ 02:36, 17 June 2006 (UTC)

It's big. The "Myth Busters" did a segment in which they explored the possibilty of decapitation by ceiling fan, and discovered it took a lot of force to sever a head - more than they were able to develop. Obviously it would be a great deal more to pull it off by blunt force. - Nunh-huh 02:39, 17 June 2006 (UTC)

Did they test that on a real person? Mr. Lefty _{Talk to me!} 02:43, 17 June 2006 (UTC)

No, that would have been difficult to budget for. They used a few person-standins. Ah, here's the synopsis. - Nunh-huh 03:04, 17 June 2006 (UTC)

I imagine, and this is just speculation, that if PCP were to remove all pain and/or care about pain, then one might be able to pull one's head so hard as to sever the spinal cord, at which point it would be impossible to continue to pull one's head the rest of the way off. --Ginkgo100 ^{talk · contribs} 04:00, 17 June 2006 (UTC)

I think that sounds reasonable, but then again, PCP addicts have done some pretty astonishing things to themselves. I remember reading about someone who peeled his face off with a broken mirror. Of course, this is different. I think if I were an abnormally strong individual with no sense of pain and a desperate, irresistible urge to decapitate myself, it might almost be possible, if I began by tearing up my neck and then snapped the spine with a single forceful jerk before I had the chance to bleed to death. The harder I think about it, the less plausible it sounds. Still, it might make for an interesting episode of CSI. Bhumiya (said/done) 05:39, 17 June 2006 (UTC)

Both this chap and this chap seem to have enough will power to cut off parts of themselves. Cutting of your own head would be a bit harder, due to the fact that you would lose conciousness pretty quickly if you didn't manage it on the first attempt and that its hard to think of a good reason for doing it to focus your mind. But that aside, i bet it would be possible with a long enough and sharp enough blade and enough power in your arms to generate the force required. I bet some of those samurai dudes could do it. Rockpocket 07:42, 17 June 2006 (UTC)

I think it would be extremely unlikely for it to happen, unless perhaps you had some kind of defect that made you have weak neck bones that would allow for the possibilty to pull off your head. A possible scenario would be this: Your head was "loose" to begin with (meaning you had some kind of bone disease or other ailment) plus you had strong arms, which would be unlikely considering how close the neck/head is to the shoulders. I wonder if anyone has actually pulled off their head out of the billions of masses. --Proficient 16:06, 17 June 2006 (UTC)

Maybe not, but a lot of people over the years have been told to pull their head in. A terribly rude injunction, I've always thought. There are so many more pleasant ways of telling a person their existence is no longer required. (lol) JackofOz 00:54, 18 June 2006 (UTC)

Help

Hello, I’m hoping you could provide me with some help. I have a physics final on Monday, and we got a review package that resembles nothing of the kind of stuff we’ve done in class. I hope these aren’t too many, here goes:

When a certain rubber band is distance x, it exerts a restoring force F = ax²-bx, where a and b are constants. The energy stored in the rubber band when stretched from x = 0 to x = L is:

a) 2aL –b

b) 2aL+2b

c) aL^3/3 + 2bL

d) -aL^3/3 + bL²/2

e) aL^/3 + bL/2

The correct answer is d. I have no idea how to get that, and the only reason I think it might be d is because it has a negative in front of the a because the Force is opposite the x

The next question: A 1kg mass moves in a straight line under the influence of a force. The potential energy is given by U(x) = 6x²-2x^3 where U is in joules and x is in meters. If the mass has a speed of 2m/sec when it is at x = 1 meter, its speed when it is at x = 0 is:

a) 0

b) 2 √2 m/sec

c) 3√2 m/sec

d) 2√3 m/sec

e) 2√6 m/sec

The answer is d. I am confused with this problem because it says “ mass moves in a straight line”, and then it mentions potential energy, which must be 0 because the object has no height. Extremely confused with this one, I think the formula might just be a trick and not actually be useful, but I have no idea. Afterwards in the next question, it asks for the acceleration (which turns out to be -6). If I knew how to do the above question I might be able to do the one after it, but I’m unsure and just completely lost. Any response would be very appreciated. – Hopelessly Screwed

I don't think we're supposed to answer homework problems, but too bad.

For question 1: When you stretch the rubber band, you're doing work on it against the restoring force of the rubber band. The key is that work (which is a form of energy) is given by $\int Fdl$. That is, the work done is the integral of the force exerted along a path (a negative sign is needed if "F" is the restoring force instead of the force exerted). In this case, the expression for the work is $W=\int _{0}^{L}(-ax^{2}+bx)dx$ (note that the signs are reversed because the work you do to stretch the band is the opposite of the restoring force). Hopefully you can integrate that to obtain $W=-{\frac {aL^{3}}{3}}+{\frac {bL^{2}}{2}}$

As for question 2, what they mean by "the mass travels in a straight line" is that it is restricted to the x dimension; i.e. there are no other dimensions in which to move. The problem is asking you to consider an arbitrary potential energy, not necessarily the potential energy due to gravity, so "height" is not an issue. For instance, this could be the potential energy of a spring that a mass is pushing against.

The key to this problem is conservation of energy. No matter where the mass goes, it's mechanical energy (potential energy + kinetic energy) will not change, (assuming no non-conservative forces like friction). Therefore, if you can figure out its total mechanical energy at some time, it will be the same at all other times. In this case, the potential energy depends only on position; you are given the expression $U(x)=6x^{2}-2x^{3}$, and kinetic energy is given (as always) by $K(v)={\frac {mv^{2}}{2}}$.

At some time, the problem says the mass has velocity 2 m/s, so it's kinetic energy is (1 kg * (2 m/s)^2)/2 which comes out to 2 Joules. At that time, it is at x = 1 m, so its potential energy is 6 * (1^2) - 2 * (1^3), which comes out to 4 Joules. Therefore, at all times (unless some outside force acts on it), its mechanical energy will be 6 Joules. When x = 0, the potential energy of the mass is 0 (zero), so the kinetic energy must be 6 - 0 = 6 Joules. Now, you can use the kinetic energy formula in reverse to figure out the velocity. $v={\sqrt {\frac {2K(v)}{m}}}$ This gives sqrt(2 * 6 Joules / 1 kg) = sqrt(12) = $2{\sqrt {3}}$.

By the way, a hint for finding the acceleration at x = 0: Since $W=-\int Fdx$, $F=-{\frac {dW}{dx}}$ and always remember that $F=ma$ where "a" is acceleration.

Hope that helps - good luck.--Bmk 05:19, 17 June 2006 (UTC)

In the first question, force $F(x)$ is dependent on $x$. Differential work done when stretching the rubber band by a length of $dx$ is $F(x)dx$. Work done in stretching rubber band from $x=0$ to $x=L$ is $\int _{0}^{L}F(x)dx$.

In the second question, it is not stated whether the force is position-indepdent (i.e. indepdent of $x$). To get an answer, some assumption is needed. Perhaps the unstated assumption is that the force is constant. With that assumption, you can calculate the work done, and therefore the increase in total energy in moving the mass from $x=0$ to $x=1$. The total energy of the mass at position $x$ is the sum of its kinetic energy (related to its speed) and its potential energy (given by the formula for $U(x)$) at that position. Given the boundary conditions, you can work out its initial kinetic energy (and therefore speed) at $x=0$.--72.78.101.61 05:11, 17 June 2006 (UTC)

It just occurred to me that in my interpretation of the second question (i.e. the "force" is external and not accounted for by $U(x)$), the question does not provide enough information to allow an answer to be calculated. Maybe Bmk's interpretation is the intended one.--72.78.101.61 05:43, 17 June 2006 (UTC)

"We haven't done calculus yet so I'm unfamiliar with integrals. Is there any other way? Thanks for helping!"

Sorry - calculus is the only way to go for a non-linear force like these. --Bmk 05:26, 17 June 2006 (UTC)

Orange peelings and antibacterial benefits

Not sure where I heard this, but I heard that orange peelings can be used to cultivate antibacterial agents such as penicillin. Am I completely wrong about this, or is there some truth to it?--24.231.16.109 04:40, 17 June 2006 (UTC)

Penicillium mold grows easily on orange peel. Just leave some oranges in a drawer or even your refrigerator too long and you will proabably be rewarded. Extracting the penicillin will be your challenge and you may want to make arrangements with your local pharmaceutical company to use their purificaction and testing facilities over a weekend, if you don't have a sterile separation and analytical lab in your basement. Next you will want to borrow some culture petri dishes and bacterial cultures in the microbiology lab of your local hospital to prove the stuff works. Good luck. alteripse 11:15, 17 June 2006 (UTC) PS: Keep in mind of course that penicillin costs maybe 10 cents a tablet.

Optics glossy/matte colours

OK, I want to explore different colours and how you can make them different. One aspect is the colour itself. Anoter aspect is the gloss, whether the colour is shiny or matte. What other optical aspects can affect the way a colour or surface visually appears? I guess there's also infrared. Can some animals see infrared surfaces? If a surface was truly infrared, what colour would a human see it as?--Sonjaaa 06:24, 17 June 2006 (UTC)

Translucency springs to mind. And yes, some creatures (such as certain species of insect) are capable of seeing infra-red. Provided all non-infrared light was absorbed, a human would see such a surface as black GeeJo ^(t)⁄_(c) • 07:30, 17 June 2006 (UTC)

Alcohols and Sodium Metal

Why is it that primary alcohols react more vigourously with sodium metal than secondary and tertiary alcohols? 138.130.252.56 09:57, 17 June 2006 (UTC)

The alkyl groups are electron-donating and thus strengthen the O-H bond in the alcohol. This makes the alcohol a weaker acid and less likely to lose a proton to be reduced by the sodium metal. The more alkyl groups present, the more electrons get pushed into the O-H bond. G N Frykman 17:30, 17 June 2006 (UTC)

software testing

Hi, i would like to know about the most used software testng tools and why the thes tools are used ?? I would also like to know about the comparitive advantage with other tools Regards Tommy

Tommy, I think you need to make your question a lot more specific to get a useful answer. What kind of software are you referring to? What OS? From what point of view (data integrity, user friendliness, vulnerability to malicious attacks, etc). --vibo56 ^talk 19:23, 17 June 2006 (UTC)

Bios Virus

hi my old laptop has not worked for a month for so now its a bit expencive to get fiexd, so i lent it to a friend who sead they would look at it. they say it has a bios virus, i was wondering what a bios virus is?

That would be a Computer virus which has somehow affected your computer's Basic Input Output System. The BIOS is a small program that tells your computer how to startup. Although BIOS viruses are said to be rare, once your BIOS has been corrupted, there is not much that can be done. The term itself is a little misleading, as the virus does not "live" in the BIOS and can not replicate itself from there. But if your computer has been affected, the terminology is the least of your worries. --LarryMac 20:33, 13 June 2006 (UTC)

Resetting the CMOS just might work. Not sure, though. -- Миборовский 05:53, 14 June 2006 (UTC)

How do you reset the CMOS? --Silex 21:02, 14 June 2006 (UTC)

Laptops are tough. CMOS is located on your motherboard so you either have to open it up to expose the motherboard (NOT recommended) or ask your Dell/IBM/HP guy. -- Миборовский 22:27, 14 June 2006 (UTC)

Well where does the BIOS virus reside if it does not 'live' in the BIOS? And would 'flashing the CMOS' work? To do that, do I have to jump some pins or something? --217.44.0.212 10:56, 17 June 2006 (UTC)

Maybe a BIOS update will correct your problem by overriding the defect. What is the exact problem with your comptuer when you say that it's not working? Is the operating system not functioning, the computer not turning on at all, or something else?--Proficient 11:17, 17 June 2006 (UTC)

To clarify, a BIOS virus should be removable by flashing (not possible if you're already at newest version, though) or by resetting CMOS by removing the battery (CMOS battery, not laptop battery) for a few minutes. It can also generally be done by changing a jumper connection. But either of those ways requires touching the motherboard - not easy on a laptop. -Goldom (t) (Review) 11:44, 17 June 2006 (UTC)

Reccommended procedure:

1. Verify the claim that there is a problem with the bios. To do this, you might check if the laptop boots normally with a bootable CD such as knoppix. If this is successful, the problem is probably not with the bios.
2. If you want to restore bios factory defaults, you can normally do this from within the menus of the bios setup program. If you pay close attention while the pc starts its boot sequence, you will see a message which tells you how to open the setup program (it might be, for example, holding down the F2 key when the pc starts). A text mode setup program will open, with a menu. Somewhere, usually on the "Exit" menu, there is an option "Load Setup Defaults". If you are certain that the bios is messed up, this should restore it. You also need to "Save changes" before exiting. --vibo56 ^talk 13:35, 17 June 2006 (UTC)

Schrodingers Equation

Ok i know the what the equation looks like but how do you solve it for a given particle of some mass whose energy contribution is V(x,y,z)using the equation. could you show it using an example. how do you solve the hamiltonian? --Debanjum 11:59, 17 June 2006 (UTC)durin

could you be more specific - when you say the energy contribution is v(x,y,z) do you mean that its energy is a function of its position in 3 dimensional space? What do you want to do? find the wavefunction that satifies certain conditions or what?HappyVR 15:16, 17 June 2006 (UTC)

See Category:Quantum models for some examples. Conscious 05:11, 18 June 2006 (UTC)

How hard would it be to write this software?

Here's something which has been on my wish-list for awhile. I'm wondering how difficult it would be to pull off.

Basically, the program would be a web browser which could simulate a locally hosted Apache server. Why do it? Because then you could write applications in server-side languages like PHP and distribute them to people easily. No need to install a whole Apache server on their machine if it is just going to be run locally. If you could combine PHP, Apache, etc. into a browser-like application itself, then you could easily distribute PHP files to people and not have to worry about all of the idiosyncracies of actually installing a server.

Does that make sense, conceptually? I want a way to easily distribute PHP programs which are made to be run off of the local machine (and not as true web applications), but the only way to currently do that is to install Apache and PHP (not simple operations, and overkill). It seems like it shouldn't be impossible to have a browser-like-application which could itself replicate the behavior of a local server.

Possible? Impossible? Hard? Easy? Already done? Any thoughts would be appreciated. --Fastfission 16:00, 17 June 2006 (UTC)

I'm not aware of any such beast. If you want to avoid installing PHP, you would either have to integrate the PHP interpreter source code into your browser code, or write your own PHP interpreter. The former is not tempting to me from a maintenance point of view, and the latter is reinventing the wheel. I'd say both sound like a lot of work. But I agree, it would be nice if the user could just download the PHP+ServerEmulator plugin, and be ready to use your PHP program. --vibo56 ^talk 19:40, 17 June 2006 (UTC)

What I was hoping one could do is just integrate Apache into the browser and then integrate PHP into that. I don't know how much re-inventing you'd have to do — all of the code for PHP, Apache, Firefox, etc. is open source.. it's just a matter of fitting it all together neatly, I suppose. Which is probably hard. :-) --Fastfission 05:20, 18 June 2006 (UTC)

One approach might be to write a user-friendly installer that installs a browser, web server and PHP interpreter at the same time. Getting it right is not easy, however. A similar thing has been done for the windows version of LyX, but I have not been able to get the installation to work properly on my system (now trying again, uninstalling everything, reinstalling each package separately). --vibo56 ^talk 08:45, 18 June 2006 (UTC)

Biological classification systems

I was wondering - regarding the classification system of plants and animals: Is there an official board or similar organisation that decides when a new classification is valid. Some of the reclassifications I've seen seem to be based on published papers - which makes sense since these things are peer reviewed - but surely getting a paper published is not all that it takes - maybe some sort of consensus rules here, I've honestly no idea how it works in practice - I assume differences of opinion do arise - how are these sorted out? Are disagreements amongst biologists worked out in a similar to conflicts on wikipedia?HappyVR 16:09, 17 June 2006 (UTC)

I look forward to an answer to this question, but I sure hope that no one in the real world resolves conflicts like we do! Melchoir 18:51, 17 June 2006 (UTC)

The International Commission on Zoological Nomenclature and International Association for Plant Taxonomy approve names proposed by the discovering scientists. Rockpocket 19:34, 17 June 2006 (UTC)

Thanks, but I'm not sure if this was the answer I was looking for - the links you provide guides to the nomenclature of species, but I was thinking in terms of when a conflict occurs regarding the placement of a given species within one or another genus - ie issues of taxonomy not naming - can anyone help?HappyVR 19:47, 17 June 2006 (UTC)

I'm sorry, i misunderstood your question. This article seems to suggest the peer reviewed publication process is how one establishes new taxonomy. One assumes, like the scientific process in most disciplines, time determines whether the community will accept the proposal, based upon further work supporting or refuting the evidence. Like everything in science, there is often no "right" answer, it comes down to who has the most convincing argument.the answer to this posting would seem to support this. Rockpocket 00:14, 18 June 2006 (UTC)

Thanks, that pretty much answers it. I was wondering if there was an organisation that 'rubber stamps' these things such as the Linnean society or 'international body of biological scientists' - I don't suppose 'rubber stamps' are in keeping with the scientific ethic though.HappyVR 00:58, 18 June 2006 (UTC)

Taxonomy is a science and it is normal to have dissensions with new theories. The dispute between traditional taxonomy and cladistics is beginning old and is still sometimes in the focus of science media. What are the criteria to sort life forms : form itself, bones, tiny characteristics, genes ? This also a question of fashions, which must evolve. --DLL 20:29, 17 June 2006 (UTC)

See International Code of Botanical Nomenclature for the WikiPedia article relating to plant taxononmy. For botany, the fights seem to be fought at the congresses where the code is decided (next one due this year?). An interesting story giving some insight into the process is: The name Acacia retained for Australian species. As far as zoological toxonomy is concerned, the situation seems to be less formal, confirming what Rockpocket said. Butler says the following in his article on the issue of Pituophis Taxonomy (I quote the whole paragraph to make the context clear, the editor's note is the pertinent bit): "Before we discuss Pituophis, I first must describe the formal and informal processes of taxonomy. Formally, there are two groups that make decisions on the names of species; the American Association of Zoological Nomenclature, which is a satellite-organization for the International Commission on Zoological Nomenclature (ICZN). Generally, if there is a published dispute regarding the name of a species, the authors will present their case to the ICZN, and they will make a ruling based on their established code. However, more typically and informally, once a name sticks, and is used frequently, then the ICZN rarely gets involved. (Ed. Note: The ICZN judges on procedures and does not get involved with species validity - that is the purview of peer reviewed journals.)" So "peer reviewed journals" seems to be the case for zoology. --Seejyb 11:04, 18 June 2006 (UTC)

The various naming committees (ICZN, ICBN etc) adjudicate a very narrowly defined set of issues to do with biological names and biological types. So questions like, "what is the type specimen for the species Homo sapiens?" or "is the name Archaeoraptor available (in the technical sense of 'available')?" are appropriate for the committees. But questions about actual relationships, like "how many genera of gibbons are there?" are outside the scope of the committees and must be settled by research, peer review, and debate. Gdr 11:19, 19 June 2006 (UTC)

Sinking lifejackets?

I have heard an urban legend that the "old" lifejackets made of cork or kapok used to lose buoyancy after being immersed in water for a long (many hours) period of time? Can anyone confirm or deny this? Thank you for time. Mieciu K 14:08, 15 June 2006 (UTC)

A styrofoam one would be better... Would you like a lifejacket like this; it's incredibly light.

Kilo-Lima|^(talk) 17:18, 17 June 2006 (UTC)

But I'm interested in lifejackets that sink. I have heared sinking lfejackets caused deaths during the USS Indianapolis (CA-35) dissater, and others but I'm unable to confirm it. Mieciu K 21:17, 17 June 2006 (UTC)

According to this NOVA transcript, early cork lifejackets had many problems: "The buoyancy is equally distributed around the body, around the front of the body and around the back of the body. So, if the person was unconscious and was lying face down on the water, he would remain stable in that position. Secondly, there was no support for the head or neck. It's really just wrapped around the top of the body, leaving the shoulders and head out of the water. And that's fine for somebody who is conscious, who is alert, who is able to hold his head out. But the head actually is very heavy, the specific gravity of the head. When a person loses consciousness, the neck muscles are failing, and then the head tends to flop forward, and they could be found floating face down in the water, inhaling the water." However, I can find no reports of cork or kapok lifejackets actually breaking down and losing their buoyancy. I would expect that cork would be fairly resilient. Consider how long corks survive in bottles of wine without breaking down. Then again, cold water might have a different effect. Also, any lifejacket, even one made from synthetic fibers, can break down if it develops a tear or becomes infested with mold, mildew, etc. I think the Indianapolis survivors may have had problems remaining upright. Their unbalanced lifejackets would have required them to constantly maintain their balance in the water. If you lost consciousness or became too tired, it would be easy to turn over in the water and drown. But I can find no evidence that life jackets actually sunk. Bhumiya (said/done) 01:36, 18 June 2006 (UTC)

IIS

I might be migrating from Apache to IIS sometime soon (and hence PHP -> ASP.NET). Here are a few questions...

• Is there an ASP.NET interfact for PhpBB? I have a lot of mods and I don't want to have to migrate my phpBB installation into another app.
• Is there a system similar to Cutenews for ASP.NET that is free? All I want is to be able to post news that is integrated into my frontpage. I'm able to design the rest.
• Is Web.config analogous to .htaccess? If not, is there a directory-level configuration file? Becuase I need to be able to define custom 404, etc. files as well as disable directory listings for certain folders, etc. And I share hosting with my dad, so I'm a subdirectory of his site.
• Is there anything else I should know?

I'll be on another host so it won't be my server. — Ilyanep (Talk) 17:04, 17 June 2006 (UTC)

ASP.NET and PHP are two entirely different programming languages. phpBB and any mods you have for it will only run under a PHP interpreter. However, it is certainly possible to run PHP scripts under IIS [14], just like it's possible to run ASP.NET code under Apache [15]. So, you can either contact your hosting provider and see if they support PHP, or move to a different forum package written in .NET. (here are some possibilities)

If you can't use PHP and are looking for a Cutenews substitute, you might want to check Category:Content management systems.

From browsing Google for information about Web.config, it does seem to serve roughly the same purpose as .htaccess. However, I'm not all that familiar with ASP.NET myself, so you'll have to ask somebody else if you have any detailed questions about it.

Anyway, hope this helps! —David Wahler (talk) 18:15, 17 June 2006 (UTC)

web.config is kind of the same as .htaccess, in that you can define application settings, including 404s (for .net processed files only, for example .aspx, but *not* for .html, because that's served up by IIS directly). Directory listings are, again, controlled by IIS, not asp.net. Once IIS7 comes out then web.config will run the whole show. Whilst I don't know of a direct cutenews replacement [DasBlog] is a .net blogging engine that uses the file system, not a database. I guess it depends what bits of cutenews you want replicated. --Blowdart 23:36, 17 June 2006 (UTC)

Just something that can display news on the front page using a design template that I give it. And then I can do something like I do include(...); in PHP — Ilyanep (Talk) 03:51, 18 June 2006 (UTC)

I've not seen something like that. And include isn't part of asp.net, you would have to embedded it as a custom control. It doesn't look hard to code, so I'm sure there must be something out there. --Blowdart 15:44, 18 June 2006 (UTC)

Well, I understand there'll be some differences between PHP and ASP.NET, but I just don't want to have to get a package that essentially codes a whole website for me. — Ilyanep (Talk) 16:50, 18 June 2006 (UTC)

Use of cows milk vs. soya milk and toothpaste

Gillian McKeith states that cows milk is bad, and that you should only drink soya milk (which I have now been doing). She states that it forms some sort of mucus on the stomach lining and that is only for use on a calf (the milk). Is she right? Also, I have begun using normal toothpaste with whitening toothpaste, using the the normal first then the whitening. Will the two toothpastes cancel each other out? Thanks, Kilo-Lima|^(talk) 17:24, 17 June 2006 (UTC)

Whether cow's milk is "bad" you might like to consider that generations of people in many (though not all) cultures have been doing it for a very long time, and that our current expectations of longevity and health are mainly concerned with people who have been drinking it at some time. You might like to consider what actual or potential problems cow's milk is claimed to cause, and consider whether there is any evidence that this is in fact the case, perhaps by comparison with other cultures who don't drink cow's milk. I have never heard of this person, but I would also check for a secondary agenda, for example whether she is also an advocate of animal rights, who might consider it desirable to reduce the many animal deaths caused by drinking cow's milk, and if so, whether you share that agenda.

Some of the racial groups who have not been drinking cows milk for a long time (see Lactose_intolerance#Biology). Obviously if you are lactose intolerant then cows milk will be bad for you. -- Chris Q 09:24, 19 June 2006 (UTC)

For the second question, what do you mean by "cancel out"? Your teeth won't become dirty again, increasing tooth decay. Notinasnaid 17:51, 17 June 2006 (UTC)

If anything, using two toothpastes will only help. I don't see what's wrong with doing a double whitening though. ;o --Proficient 19:56, 17 June 2006 (UTC)

I'd be more worried about trusting someone who can only call herself a Doctor because of a "mail order" PHD from a non-accredited university (The American College of Nutrition). Please, consider your source. --Blowdart 20:15, 17 June 2006 (UTC)

Humph, that source does not know the difference between the UK and England, especially when Gillian McKeith is Scottish. Kilo-Lima|^(talk) 20:49, 17 June 2006 (UTC)

Are you complaining about the "London, England" bit on that page, because that's the only part I could see that you could make that comment about; and it is, obviously, accurate. --Blowdart 23:37, 17 June 2006 (UTC)

Ms McKeith is likely referring to rennet, since there is nothing else resembling her fanciful notion of a milk-specific "mucous lining" in calves. Soy milk as you buy it is a highly modified synthetic product. The rate of allergy is 5 to 20% (see [16]) and there is about a 50% cross-allergy with cows' milk. For young woman, skim milk would be the drink of choice, since soy contains neglible amounts of calcium. Apart from allergy differences, and the different fat compositions of the two products, there is no scientific proof that there is any benefit in drinking synthetic milk (see [17]). In the two books of this person that I have read, it is sometimes difficult to decide whether the writer is naively propagating untruths as valid science, or whether she is deliberately lying to make money. --Seejyb 09:30, 18 June 2006 (UTC)

I don't know about this "mucus-lining" stuff, but there is no evidence whatsoever that drinking milk decreases your risk of osteoporosis. Check this study by the Harvard School of Public Health out. Here's a quote from the conclusion of that study: "An adequate vitamin D intake is associated with a lower risk of osteoporotic hip fractures in postmenopausal women. Neither milk nor a high-calcium diet appears to reduce risk." It's an amazing dairy-industry conspiracy - somehow everyone thinks milk keeps your bones healthy, but it just doesn't seem to be true. And as for soy milk, I don't know what Seejyb means by "a highly modified synthetic product". It's made with a very old process developed in the 1st century BC (see Soy milk) It's basically, "grind the beans in water, then strain out the milk". --Bmk 13:56, 18 June 2006 (UTC)

Stable beer

Why is it that a full can of beer seems a lot more stable when upright than the same can empty. (And dont say because its not yet drunk! Ha Ha!)--Light current 18:32, 17 June 2006 (UTC)

It's more massive, so you have to hit it harder to knock it over. I don't know if you're aiming for something more profound...? Melchoir 18:48, 17 June 2006 (UTC)

I agree with Melchoir. If you have an empty can and a full can you can do a very simple experiment to see if there really is a difference: Push the very top of the empty can a tiny bit then let go. If it doesn't fall over, push the same place a little harder, let go, repeat until it falls over. Do the same again with a full can and see if you have to push them the same distance until they fall. Obviously you'll have to push the full can harder because it is more massive, so you'd want to pay attention to distance or angle and not force. 128.197.81.181 18:58, 17 June 2006 (UTC)

Wellll... it all depends on what one means by "more stable" anyway. The major difference between the two cases will be the force, not the angle, required to tip the can. Melchoir 19:10, 17 June 2006 (UTC)

Yeah but surely the centre of gravity is about the same in both cases?--Light current 19:02, 17 June 2006 (UTC)

Maybe, but the dynamics of a rigid body are determined by its mass and moment of inertia as well as its center of mass. Melchoir 19:06, 17 June 2006 (UTC)

Aha! I think you may have hit on it here! Its probably the moment of inertia that is much smaller when empty. But Im going to do a few experiments with a large number of full, then empty cans! How they get from full to empty, Ill leave to your imagination! %-)--Light current 19:15, 17 June 2006 (UTC)

Ah, the spirit of scientific inquiry! Melchoir 19:26, 17 June 2006 (UTC)

Yes: the suffering we have to endure in the persuit of knowledge! Yes! now the result of drinking the first can experiment! Comparing a full can with an empty one I noticed that the max tipping angle was approx the same for both. (say 30 deg from vert - I didnt actually measure it). But, if the cans are pushed below this critical angle and then released, the full can regains its upright position with no oscillation, whereas the empty can totters back and forth quite a few times before coming to rest. Any ideas on that one? Anyway, must get back to the lab! %-)--Light current 19:48, 17 June 2006 (UTC)

That's quite interesting. --Proficient 19:59, 17 June 2006 (UTC)

I guess the sloshing motion of the liquid inside helps to dissapate energy, plus other factors.HappyVR 20:07, 17 June 2006 (UTC)

Yesh-- Im coming to that conclushion myshelf!! %-)--Light current 20:14, 17 June 2006 (UTC)

Building a bomb

I'm writing a fictional work (actually a Live action roleplaying game) in which somebody needs to build a simple bomb. According to time bomb, all one really needs is a battery, a watch, and some explosive material. What kind of explosive material? Where would a teenager on a colony on Triton (a new colony, not so different from the stereotypes of the American Old West) get such a thing? Like, if there's blasting crews on the colony, could he just lift some? What are the steps involved in making a bomb? I looked for instructions for building a simple bomb online, but it turns out it's less widely available than the scaremongers would have you think. And I don't need to actually do it myself, just describe in very rough terms what would be needed. moink 19:58, 17 June 2006 (UTC)

Maybe your character can steal some c-4 from a construction site as well as some blasting caps. --Proficient 20:01, 17 June 2006 (UTC)

Just make sure to explain that you character was well-trained in his former life, including Afghan, Irish, &c. references, and do not go into bomb making details : the reader shall know enough. --DLL 20:15, 17 June 2006 (UTC)

Hmmmm... I'm trying to make him a pretty lame loser character who doesn't really know what he's doing, but does some really basic research and figures out how to build a simple bomb. We're trying to make it hard for him to accomplish this, since it screws over the other characters pretty badly if he succeeds. moink 20:18, 17 June 2006 (UTC)

Are there weeds on this colony? He could use the ever popular weedkiller ( potassium chlorate or sodium chlorate) and sugar. Theresa Knott | Taste the Korn 20:43, 17 June 2006 (UTC)

If he's not looking to do too much damage, how about the ingredients in the Gunpowder article? --hydnjo talk 20:50, 17 June 2006 (UTC)

If they farm on this colony, perhaps they have ammonium nitrate around. Powerful, common, explosive. --Fastfission 05:13, 18 June 2006 (UTC)

According to Triton (moon), there is a lot of Ammonia present. Methane and Nitrogen are abundant in the atmosphere. If you have some water, I'm sure a chemist could whip something up for you. Dmn € Դմն 11:37, 18 June 2006 (UTC)

Does it have to be a bomb, or can it just be an explosion? Any fine powder should be very dangerous if it forms a mist. See Flour and Lycopodium. The lycopodium article has links to movies. --Kjoonlee 14:51, 18 June 2006 (UTC)

Well, just something that makes sense for my character to put together from a few different pieces and "set off" while he tries to get away. I think I'me going with C-4 and some wiring and a battery. moink 07:43, 19 June 2006 (UTC)

e-mail address harvesting?

I’ve been getting a lot of e-mails from various phony senders. They are without a subject line, have no content, and are addressed to “unlisted recipients.” What is going on? Is this some kind of e-mail harvesting, or maybe something worse? --Halcatalyst 20:46, 17 June 2006 (UTC)

Can you post the header? Theresa Knott | Taste the Korn 20:51, 17 June 2006 (UTC)

An example follows. --Halcatalyst 21:33, 17 June 2006 (UTC)

Received: from ams018.ftl.affinity.com 

(lvs00-fl-n18.ftl.affinity.com?[216.219.253.56](misconfigured sender))

          by sccqmxc94.asp.att.net (sccqmxc94) with ESMTP

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Durn. Can somebody tell me how to display this native? (with line breaks) Thanks. --Halcatalyst 21:38, 17 June 2006 (UTC)

Done. --cesarb 21:42, 17 June 2006 (UTC)

Thank you, CesarB! --12.217.186.109 02:34, 18 June 2006 (UTC)

It's very possible that the senders have their own SMTP servers, thereby eliminating the need to send a "To" address to another SMTP server and allowing them to directly interact with your ISP's mail servers without having to go through the regular process of specifying a "To" address to a third-party SMTP server. There are many possibilities; spammers use lots of different tricks. -- Daverocks (talk) 12:19, 18 June 2006 (UTC)

I wonder why theere is no content? Could the spammer be accomplishing something nevertheless? --Halcatalyst 13:14, 18 June 2006 (UTC)

I occasionally get spams with no content, which is rather confusing. A possibility that comes to mind is that they've set up a dummy email account to send from and they're tracking bounced emails to trim down their lists. 128.197.81.181 18:28, 18 June 2006 (UTC)

I suppose if they're sending out a couple million spams it might be useful to delete 300,000 (or even 50,000) bad addresses, especially if they have automated means to update the lists. But it's hard to imagine spammers being that concerned about efficiency. --Halcatalyst 19:18, 18 June 2006 (UTC)

Ergonomical Sleeping

If a futon is ergonimical to sleep on because of it's hardness, how egonomical to sleep on, is a camping mat on a hard floor? --Username132 (talk) 22:51, 17 June 2006 (UTC)

You seem to be assuming that futon has a more universal meaning than it actually does. In English, it seems to refer to any sort of folding bed, aka sofabed, though the original Japanese is something completely different and very specific. I slept on a very soft western futon during my university days.

Regardless, if I take your question to mean "If firm beds are considered ergonomic, is a camping mat on a hard floor equally so?" then I can explain why the answer is no. The futon in question (yours, I assume) isn't good for your back because it's hard, but because it only gives to a small degree (hence, firm), allowing your back to straighten instead of lying limp like it would on a very soft bed. A camping mat on a hard floor has no give whatsoever, and thus does not allow for natural body contours and ends up giving you stiff bones in the morning. As a person that rather enjoys sleeping on a hard floor, I can vouch that it is ergonomical to a certain degree, especially after long periods sleeping on a soft bed, but without a firm cushion underneath you quickly develop cricks in your neck and shoulders, and I guess that's why there are so many doctors who cure that sort of thing around these parts in Japan.  freshofftheufoΓΛĿЌ  05:28, 19 June 2006 (UTC)

June 18

Old Alcohol

I inherited a stock of alcohol in sealed bottles - over 30 to 40 years old. Is it safe to be drinking that? — Preceding unsigned comment added by 69.118.234.15 (talk • contribs) 21:14, 17 June 2006 (UTC)

In the case of wine, quite possibly, although it may have passed its best. Whisky (and whiskey) may be OK to drink too, but you may want to re-ask this question at the science reference desk, as they may be more able to help answer your question. EvocativeIntrigue _{TALK | EMAIL} 21:40, 17 June 2006 (UTC)

Moved from the Miscellaneous section by vibo56 ^talk.

If it's brandy in your bottles, then it will probably be very good indeed. --Kurt Shaped Box 00:26, 18 June 2006 (UTC)

The alcohol you are referring to is ethanol, right? Otherwise, you probably wouldn't want to drink it :-) ...

If it is wine or anything stronger, I think it would be safe to taste it. And if the taste's ok, I think it would be safe to drink it. But to be on the safe side, wait a couple of days until other contributors have had their say! --vibo56 ^talk 00:19, 18 June 2006 (UTC)

Or send another contributor the alcohol and see if they survive after a few days. --M1ss1ontomars2k4 ^{(T | C | @)} 00:20, 18 June 2006 (UTC)

And if they die, the traditional rule for food-tasters applies. They get a cemetery or a crematorium named after them. (lol). JackofOz 00:35, 18 June 2006 (UTC)

Well, depending on what sort of beverage we are talking about, volunteers shouldn't be that hard to find... :-) --vibo56 ^talk 00:42, 18 June 2006 (UTC)

The thing is, if the yeast which creates the alcohol is still in there, it can take the alcohol and further convert it to Ethyl Aldehyde, and then to Acetic Acid (vinegar). Usually the yeast is removed to prevent his from happening, and with high content spirits the alcohol content can get to toxic levels for the yeast.

My guess is that it would be safe, but like was said above, it could just taste awful. —Mets501 (talk) 02:29, 18 June 2006 (UTC)

Well, you shouldn't rule out the thought of selling them. Since they are so old, you might get a good deal if you can -prove- that they are 30 to 40 years old. --Proficient 14:40, 18 June 2006 (UTC)

Even better, drink it, buy something cheap to refill the bottles, then sell it as well. Black Carrot 21:52, 18 June 2006 (UTC)

My budgerigar's eyelids

This is something that I first noticed years ago, with my very first pet budgie but completely forgot about until I read all the budgie-related questions on here. Is there any particular reason that when a budgie blinks, its bottom eyelid moves up to meet the top, as opposed to the top eyelid moving down to meet the bottom, as in humans? Is there any particular advantage to this configuration, or is it just a case of two very different species evolving from two very different evolutionary lines and arriving at different solutions for the same problem? --Kurt Shaped Box 00:50, 18 June 2006 (UTC)

Are you sure this isn't a third, inner eyelid you are seeing, in addition to the normal eyelids ? Cats have this, too, and I assume it's useful for removing debris (like fur, in the case of a cat) from the eyeball. StuRat 23:51, 18 June 2006 (UTC)

Na. It's definitely his bottom eyelid - I've been sat watching him for the past ten minutes. When he blinks, the bottom lid moves up to meet the top one. Go figure. --Kurt Shaped Box 11:25, 19 June 2006 (UTC)

How does my Electric toothbrush recharge itself?

I've got a Braun toothbrush which has a solid plastic casing. I recharge the toothbrush by placing it on a small recharging unit that also has a solid plastic casing. The unit is plugged into the mains, but how does the toothbrush recharge when there are no metal contact points on the charger or the toothbrush?

Psychonaut3000 01:44, 18 June 2006 (UTC)

Assuming you have't missed the metal contacts I'd assume through electromagnetic induction. A coil of wire with an oscillating (AC possibly highfrequency) current in it would induce an oscillating electric current in a pickup located inside the tootbrush. This could be used to charge a battery. Sorry I can't find a good page to explain the process..HappyVR 01:54, 18 June 2006 (UTC)

Yes as described here. Also the early models of implanted artificial pacemakers used this method of recharging its batteries. --hydnjo talk 12:08, 18 June 2006 (UTC)

You can test this by dangling a small piece of steel inside the charging socket: the metal ferrule on a pencil works well, as should a small screwdriver. If you can feel a vibration, it uses magnetic induction. --Serie 20:06, 19 June 2006 (UTC)

HIV Transfer

If I have a small cut on my penis, and I am getting a blowjob from someone that has HIV or AIDS, will I get HIV? I was reading an article and it mentioned that the HIV virus is in saliva also, thanks

There is risk, but it does not guarantee infection. Any body fluid exchange can carry the virus, but the operative word is CAN, not for certian. Also consider that the virus is fairly fragile, and does not survive very long outside the body. I would strongly reccomend you get yourself checked, this virus is pretty ugly once it gets a hold of you.

See #HIV. Conscious 05:07, 18 June 2006 (UTC)

You shouldn't risk it. --Proficient 14:47, 18 June 2006 (UTC)

Regardless of the cut, you shouldn't risk it. Black Carrot 21:50, 18 June 2006 (UTC)

And you should shave more carefully. - Nunh-huh 11:24, 19 June 2006 (UTC)

PNG graphics transparency

I've noticed that some PNG graphics on Wikipedia that are shown with a transparent background within the article actually have a blueish background. Here's an example:

In the article PNG this same image has a transparent background.

Why does this happen? How do I make the background display as transparent?--Anakata 02:15, 18 June 2006 (UTC)

Internet Explorer cannot handle transparant PNG images, and often displays them (on Wikipedia) with a blue background. You could try using Mozilla Firefox; that will fix the problem. —Mets501 (talk) 02:24, 18 June 2006 (UTC)

I recommend Firefox as well, but here's a fix for MSIE users who can't switch: Wikipedia:Tools#Internet_Explorer_alpha_transparency. It isn't failsafe, though, so beware. --Kjoonlee 12:41, 18 June 2006 (UTC)

Can you explain me the types of sugar?

I want to know everything about types of sugar like table sugar,milk sugar,starch sugar and fruit sugar. Please help me with this topic.--59.144.254.49 03:41, 18 June 2006 (UTC)

See sugar and carbohydrate. They will certainly point you to sucrose, lactose, amylose, and fructose, the sugars to which you may be referring. Cheers, David Iberri (talk) 03:45, 18 June 2006 (UTC)

Web based file sharing

I've recently been asked by an online group in which I'm active if I could establish some sort of web-based file sharing tool... Pictures, audio files, and possible applications. There are several groupware packages that incorporate some type of upload/download for members but, along with that functionality, one is bombarded with features that are not, in this case, needed.

Is there a web-based file sharing package (for linux?) that might work for this group? I've read through File sharing but the article is concerned mostly with P2P stuff. Thanks so much for any guidance you guys (and gals) might be able to provide! --Chiacomo ^talk 04:45, 18 June 2006 (UTC)

Have you considered an FTP server? –Mysid^(t) 07:52, 18 June 2006 (UTC)

MILF!

Why is it that some teenage boys/young men are attracted exclusively to women in their 40s? Is there a scientific/evolutionary explanation for this? In terms of reproduction, this would seem to be counterproductive (without trying to sound too veterinary, women of that age are past their prime when it comes to breeding). --84.65.31.248 05:48, 18 June 2006 (UTC)

I'm not sure what you mean by "exclusively". I doubt young/men boys are alone in their lust for women in their 40s (one would think their husbands might also have a sexual interest in them). Nor are 40 year old women the only object of teenage boys desire (otherwise teenage girls wouldn't have many boyfriends). That notwithstanding, its an interesting question. From a psychosexual point of view, one could argue that teenage boys are experiencing the junction between cutting their ties to the primary female in their life (their mother) and experiencing sexual feelings for the first time towards another woman. Thus an older woman can fulfil both their need for a caring, maternal relationship and a sexual relationship. That someone could fulfil both roles could manifest as a strong sexual attraction in a young males. I'm sure Freud would having something to say about that. Rockpocket 08:05, 18 June 2006 (UTC)

Maybe I'm misremembering my youth, but I seem to recall that teenage boys lust after anything with two legs and a pulse. That said, Rockpocket is probably on to something with his reference to Freud. There are also undoubtedly teenage boys who find that most girls their own age are immature, just like (many more) teenage girls find boys their own age immature. --Robert Merkel 11:37, 18 June 2006 (UTC)

I think big tits have something to do with it?HappyVR 13:17, 18 June 2006 (UTC)

Well, make a decision. Do you think that or do you not? ;) My opinion more or less echoes theirs, without the Freudian part. Evolution probably has little to do with it. Black Carrot 21:48, 18 June 2006 (UTC)

On the question of evolution, it may have something to do with the female reproductive peak much later in life (I think 35yrs. is typically cited,) so perhaps the male evolutionary response is to seek out those females most likely to bear children?

The thing about the sexual peak at 35 doesn't jive with evolutionary/reproductive success theories, because women begin to lose fertility in their late 20s or early 30s. A much more documented phenomenon is of older men seeking out women in their early 20s, because these women are more fertile. At 35, the risk is much higher for pregnancy complications and birth defects. My pet ideas:

1) When (straight) teenage boys first become attracted to women, some of them might find themselves more attracted to "unobtainable women" such as celebrities, models, and older women, because there isn't any real chance of having to interact with them. They can avoid the fear of being rejected or humiliated, because they're obviously not going to hit on (or get hit on by) their friend's mom.

2) Teenage girls are just as nervous/self-conscious as teenage boys, while older women are generally much more confident and comfortable with their sexuality. Confidence is a huge turn-on for most people. TheSPY 15:07, 19 June 2006 (UTC)

Diffusion and Osmosis

What does "concentration gradient" and "chemical potential" mean in the context of diffusion?

I am often confused by the idea of "diffusion". THe following is my idea of what's diffusion?

"The dispersion of random moving particles from high concentration to low concentration"

For the definition of osmosis:

"The diffusion of water from low concentration to high concentration"

Please correct any wrong ideas thank you!

Concentration gradient is the rate of change in the concentration of a substance along a given direction. In the context of diffusion, say you have a region of high concentration of a substance and a region of low concentration of the substance. As you move from the region of high concentration to the region of low concentration, the concentration changes gradually. Concentration gradient in this context is a measure of how rapidly the concentration changes as you move from one region to another.

In osmosis, you have one or more dissolved substances (solutes) dissolved in a solvent (of which water is a common example). Osmosis is the diffusion of solvent across a semi-permeable barrier from a region of low solute concentration to a region of high solute concentration. Osmoisis is a form of diffusion. (In the definition of osmosis you gave, "concentration" is that of the solute(s), NOT of the solvent)--72.78.101.61 12:52, 18 June 2006 (UTC)

Why does the particles MUST move from high to low concentraiton?

The net movement of particles from a region of high concentration to a region of low concentration is the result of the movement of many individual particles. For simplicity, imagine that there is a (real or imaginary) boundary separating the two regions and assume that particles are equally free to cross the boundary in either direction. In order for a particle to cross from side A of the boundary to side B, there first needs to be a particle on side A (near the boundary). If there's a higher concentration of particles on side A (than side B), probability dictates that the expected number of crossings from side A to side B is higher than in the reverse direction. Note that the net flow of particles is a statistical average. Particles cross the boundary in both directions. It's just that there are more crossings in one direction than in the other.--72.78.101.61 14:50, 18 June 2006 (UTC)

Case in e-mail addresses

I've looked at the e-mail address article, but it doesn't seem to be clear on whether upper-case and lower-case letters are treated as different characters in e-mail addresses. Either they are or someone doesn't want to talk to me- which is it? Henry^Flower 08:16, 18 June 2006 (UTC)

It depends on the software which receives and routes the e-mail. There are many different software solutions for this, and some will distinguish between upper and lower case in addresses. However, upper and lower case unaccented Latin characters should not be significant in the domain name (that is, the part after the @ sign) according to the rules of DNS; however it remains possible that some e-mail software will still care. For this reason, best practice in reproducing an e-mail address is to use exactly the case originally given. Notinasnaid 08:32, 18 June 2006 (UTC)

Thanks! I'll try some permutations. Henry^Flower 08:35, 18 June 2006 (UTC)

Also, some web-based email services like Gmail and Hotmail force all usernames to be lower-case, which helps. But with email addresses residing with ISPs, their policies all vary. -- Daverocks (talk) 12:35, 18 June 2006 (UTC)

See e-mail address. The local part of the address is case-sensitive, the domain name is case-insensitive. However, not all e-mail software properly implements RFC 2821. Gdr 19:09, 18 June 2006 (UTC)

Health

What can cause a cancerous tumore of the brain?

Try the article on brain tumor and google. Weregerbil 11:21, 18 June 2006 (UTC)

Reading too many Wikipedia articles is the cause. :-) StuRat 23:44, 18 June 2006 (UTC)

drugs

1.What are the functions of drugs? 2.What are the helpful and harmful benefits of drugs to people?

Try the article on drugs and the articles on medication and recreational drugs linked therein. Also google is your friend. After doing some research on your own please ask specific questions on anything you can't find on Wikipeda and the net. Weregerbil 11:23, 18 June 2006 (UTC)

Some of them make you better if you take the right amount. Some of them make you sick if you take the wrong amount. --Kurt Shaped Box 11:30, 18 June 2006 (UTC)

I'd say they all make you better if you take the right amount, and make you sick if you take the wrong amount. In some cases the right amount would be "none", but in the words of ... hell, I don't even know ... "Of course too much is bad for you - that's what too much means!" Confusing Manifestation 09:30, 19 June 2006 (UTC)

Turkish spider

Does anyone know what kind of spider this is? I took these pictures in southern Turkey, near the village of Aglasun. Many thanks, pjd 11:50, 18 June 2006 (UTC)

I'm no expert, but the head reminds me of windscorpions. --Kjoonlee 13:26, 18 June 2006 (UTC)

Many thanks Kjoonlee, I just read the article and you are probably right. The eyes on top of the head, the pincer 'jaws' and the long pedipalps 'giving the appearance of two extra legs' all point to a windscorpion. pjd 14:20, 18 June 2006 (UTC)

biology question.

Potato plants bear seeds and flowers yet they never grow from their seeds.Why?--59.144.242.244 12:19, 18 June 2006 (UTC)

Some varieties of potato produce seed, some don't. The ones that do can be grown from seed. It's just that they germinate slowly, the plant grows smaller, and produces less harvest than potatos grown from tubers (the tuber has all that easy-to-use energy that gives young plants a jump start on life.) So commercial production starts from tubers. Potatos are occasionally grown from seed by researchers when they try to produce new varieties by cross pollination. Weregerbil 13:07, 18 June 2006 (UTC)

Non-microwavable security devices

OK, so i've just been to the supermarket and bought some razor blades. They come fully equipped with a sticker saying: "This product contains a non-microwavable security device". Presumably this is some kind of RFID tag. My questions are:

1) Is a RFID tag any more or less microwavable than a razor blade? The razor blades don't come with a 'Don't put me in the microwave' warning.

2) Why would you want to microwave a packet of razor blades anyway (unless you were into making sparks?)

--Chris 12:53, 18 June 2006 (UTC)

Presumably that's a safety warning against attempts to destroy any RFID tags embedded in the product by "cooking" the product in a microwave.---72.78.101.61 13:09, 18 June 2006 (UTC)

It sounds like a dare to me!

It's probably a standard label placed on a number of items, some of which happen to already have metal components. Black Carrot 21:44, 18 June 2006 (UTC)

Firefox problem

Hello. I am trying to download Google's notebook, and I keep getting this darn porblem about it not letting me install the software. Then, below the address bar, it sasys "Software installation is currently disables. Click Edit Options... to enable it and try again." I then added "tools.google.com" to the allow list, but it still doesn't let me download it. I followed all of the instructions on the page that helps you, but to no avail. Any ideas? Thanks a lot. Iolakana|^(talk) 16:22, 18 June 2006 (UTC)

it's unlikely, but could be a profile problem. Try removing your Firefox profile and starting again (it'll remove all your cache/bookmarks, though). Heres how; Close all Firefox windows and make sure the firefox process is stopped. Assuming you're using windows go Start -> Run "Firefox.exe -Profilemanager" (if you're not running Windows you can use the same option through command etc), delete your current profile, then create a new one, then restart Firefox. There's a chance that might fix it as it could be due to some mismatching. I suggest you try this as a last resort only though. -Benbread 21:55, 18 June 2006 (UTC)

Scientific Reviews

Why do scientists write reviews and how long does it take?

What types of reviews are you talking about? Book reviews, article reviews, peer review? (Movie reviews?) The one type of review which is most associated with scientists is the peer review, take a look at our article on that. As for how long it takes, surely it depends on the subject matter and the scientist. --Fastfission 18:22, 18 June 2006 (UTC)

In my mind the sort of review most associated with scientists is a review article. Research articles describe results from a particular experiment or a set of experiments. Review articles, on the other hand, describe the results from a set of research articles, attempting to unify various results with a simpler explanation, usually trying to argue that the various results support the author's personal theories. How long it takes depends on a lot of things: how well the author knows the literature, the intended length of the review/amoung of content to be included, number of authors writing the review, number of hours per day spent writing, etc, so it's hard to give a good answer. Hope that helps. 128.197.81.181 18:39, 18 June 2006 (UTC)

Yeah, I was referring to review articles (cf. movie reviews!) Who funds the scientist writing a review article? --Username132 (talk) 20:59, 18 June 2006 (UTC)

I'm pretty sure whomever is funding the person's work is funding any review articles the scientist writes as well. Unlike actual experiments which can require specific funding for equipment, lab workers, chemicals, etc., writing a review paper really only requires time, so there isn't really a need to request extra funding. 65.96.221.107 22:59, 18 June 2006 (UTC)

I have written a number of reviews in my time and, in my experience, they can take anything from 10 hours to 50 hours of work depending on length and how much i know about the relevent primary literature off hand. I often get a student or post-doc to write a draft first, so that cuts down on my time. In most cases there is no payment for writing the review (though occasionally there may be a token fee paid if it is an invited review) so my time is paid for off research or core grants. Though, as is the case with most scientists, grant, review and paper writing tends to happen on your own time (at weekends and evenings). Rockpocket 02:49, 19 June 2006 (UTC)

CSS DIV issue

I've been trying to make a workmanlike image map using primarily CSS. After scouring Google for examples of how to do this, I've ended up with what seems to be a relatively basic approach. It almost works...

Basically, I have a menu image with a number of places to click on little links to other pages. The basic CSS behind it is as follows:

#headermenu { background: url("header-menu.jpg") no-repeat right; background-color: #000000; height: 25px; width: 100%; } 

#headermenu .aboutbtn { 
	border: 1px solid red;
	position: relative; 
	left: 440px; 
	width: 51px; 
	top: 2px; 
	height: 18px;
}

#headermenu .archivebtn { 
	border: 1px solid red;
	position: relative; 
	top: -18px; 
	left: 518px; 
	width: 66px; 
	height: 18px;
}

#headermenu .linksbtn { 
	border: 1px solid red;
	position: relative; 
	top: -38px; 
	left: 613px; 
	width: 48px; 
	height: 18px;
}

#headermenu .contactbtn { 
	border: 1px solid red;
	position: relative; 
	top: -58px; 
	left: 689px; 
	width: 64px; 
	height: 18px;
}

Pretty straightforward, yes? (I know it would be more straightforward if the positions were "absolute" but that doesn't work with the arrangement I have). The little red borders are just there so I can see where the links are set for at the moment.

The HTML which uses this looks like so:

<div id="headermenu">
	<a href="about"><div class="aboutbtn"></div ></a>
	<a href="archive"><div class="archivebtn"></div></a>
	<a href="links"><div class="linksbtn"></div></a>
	<a href="contact"><div class="contactbtn"></div></a>
</div>

Now this all comes up perfectly on the screen. The menu image is there, the links are in the right place, they do what they are supposed to do.

Except that the entire menu image itself is also a link, and goes to wherever the first button is set to go. This is not what I want it to do, nor is it what it seems to me that it should do (I haven't told the entire headermenu to be a link, just the div inside it... right?).

What could be causing this? It happens in all browsers I try it on. I find it perplexing because I can't see why it thinks it should do this, much less how to prevent it from doing it. --Fastfission 18:31, 18 June 2006 (UTC)

The HTML 4.01 Transitional DTD says: <!ELEMENT A - - (%inline;)* -(A) -- anchor --> I don't think you're allowed to put <div> inside <a>, because <div> is a block-level element, not an inline-level element. --Kjoonlee 18:54, 18 June 2006 (UTC)

Have you tried using <span>, the inline equivalent of <div>? --Kjoonlee 18:57, 18 June 2006 (UTC)

Turning the <div class="aboutbtn"> into <span class="aboutbtn"> made it so that the links don't appear at all. :-( CSS sometimes makes me sad... --Fastfission 19:02, 18 June 2006 (UTC)

Oops. I didn't expect that.

<div id="headermenu">
        <a href="about.htm"><img src="about.png" alt="about" class="aboutbtn"></a>
        <a href="archive.htm"><img src="archive.png" alt="archive" class="archivebtn"></a>
        <a href="links.htm"><img src="links.png" alt="links" class="linksbtn"></a>
        <a href="contact.htm"><img src="contact.png" alt="contact" class="contactbtn"></a>
</div>

How does this work? You need something inside the anchor if you want to click it. --Kjoonlee 05:02, 19 June 2006 (UTC)

Well, I could try that as a last resort, but it's not at all what I'm trying to do (I was trying to make an imagemap, i.e. links positioned in regions on an image)... --Fastfission 13:56, 19 June 2006 (UTC)

Here's something else that drives me bonkers. If I use SPAN and make the positions ABSOLUTE, then it works. However it won't (unsurprisingly) stay "glued" to the menu image (If I resize the window, they are not in sync at all). If I make the positions RELATIVE then the links don't show up at all. What the heck? --Fastfission 14:37, 19 June 2006 (UTC)

OK, I got it to work with the original code, more or less. A lot of my troubles were stemming from the fact that I termined by curly bracket on the line before the CSS posted here with a semicolon (habit), which apparently made all hell break loose. But once I removed that semicolon, it works fine. Sigh... --Fastfission 15:08, 19 June 2006 (UTC)

Blade Sharpening

In the film 'the colour purple', there is a lady that sharpens a razor on what appears to be a leather strap. How is a leather strap able to sharpen a metal razor and is this method still applicable to modern-day blades? --Username132 (talk) 20:54, 18 June 2006 (UTC)

You might be interested in our articles at straight razor and strop. — Lomn | Talk 21:27, 18 June 2006 (UTC)

On the other hand, you might not. Neither one answers your question. - Nunh-huh 23:44, 18 June 2006 (UTC)

As I understand it (i.e., in my limited understanding), strops aren't very good at sharpening, but they're good enough that it can stretch out the time needed between "real" sharpenings. If you think of the use of a razor, the thinnest parts have a tendency to "fold over" back in the opposite direction of the razor's use. This "folding over" makes the edge less keen. A few strokes on the strop helps reverse this and tide you over until the razor can be resharpened with a more efficient tool. - Nunh-huh 23:48, 18 June 2006 (UTC) Leather strops are used with an abrasive polish (absorbed by the leather). - Nunh-huh 03:29, 19 June 2006 (UTC)

I don't remember that part of the movie (i barely remember seeing it at all.) But, any good Boy Scout knows that an essential part of knife sharpening (for wood carving purposes, at least) is use of a 'slipstick' which is essentially a piece of leather bound to a small plank of wood. It is used after the knife has been sharpened on a stone, to break away the fine edge on the blade left from the stone.

Static On My Person

If my skin is non-conductive at low voltages then how does touching an earthed object with one hand remove static from my entire body? --Username132 (talk) 22:18, 18 June 2006 (UTC)

For one thing, "static" is the same as high voltage. Second, your skin isn't non-conductive. Instead, skin is both a bad insulator 'and' a bad conductor. It's full of moisture, particularly salt water, and is backed up by very wet and salty meat. In other words, it's a resistor. Touch your finger to the leads of an ohmmeter, and you'll see a reading somewhere between thousands of ohms and hundreds of thousand of ohms. If your skin was made of metal, then it would only take a few nanoseconds in order to discharge your entire body by touching Ground. Instead it takes many microseconds: it's still almost "instant," yet it's much slower than what metal would do. --Wjbeaty 22:32, 18 June 2006 (UTC)

So what sort of features of a person would mean they would have a very high/very low resistance? I have a friend who can literally touch one finger to a wire and then touch another finger (on his other hand) to the other and of a wire and be able to complete the circuit, on voltages < 9v! We call him the human wire... -Benbread 22:42, 18 June 2006 (UTC)

I am a person with a low (electrical) resistance. This is becasue I sweat profusely on the palms (and feet). When I touch the leads of the ohmmeter, I registered the lowest resistance in my class (I don't remember how much). Even though I don't sweat all over my body, I suppose that the sweat on my palms makes a very good contact with the leads, thus allowing electric current to pass easily. The worst part was that I frequently got small electric shocks from the bare wires of the 5V circuits we used to build in our electronics labs. I even used to feel the tingle if I put my fingers across a conducting diode (~ 0.7V). It is a different issue that many of my friends didn't believe me. -- Wikicheng 04:14, 19 June 2006 (UTC)

This is the same thing the E-meter does in Scientology. The conduction at the surface, i.e. how much you're sweating, is very important in the total resistance, which is how the E-meter does a good job of measuring stress. (or engrams I guess, depending on your beliefs). I believe one of the measurements of a polygraph may operate on a similar principle. moink 07:18, 19 June 2006 (UTC)

Please help me identify this insect

Unknown insect

I found this very odd insect in my parents house, they live on the north south end of Vancouver Island in Sidney, British Columbia.

I have never seen such an insect around here before and was wondering if anybody could identify it. It is about 1 inch long and was sitting high on a wall near the ceiling. HighInBC 23:42, 18 June 2006 (UTC)

Check the Weevil article. Since Sidney is on the ferry route there is a good chance it hitched a ride. Very common in the US. ...IMHO (Talk) 06:52, 19 June 2006 (UTC)

Just as an aside, Sidney is nowhere near the North end of Vancouver Island. It's at the North tip of a small peninsula near the South of the island. moink 07:15, 19 June 2006 (UTC)

Oops, I got the words mixed up. Thanks for the info! HighInBC 12:32, 19 June 2006 (UTC)

June 19

Arrowroot Flour

I have ground arrowroot and I have flour - in what ratio do I mix these to make 'arrowroot flour'? --Username132 (talk) 02:32, 19 June 2006 (UTC)

Um, I think "arrowroot flour" simply means flour made from arrowroot, not arrowroot mixed with wheat or whatever. So I'd say 100:0. Depends what you want to use it for, though. —Keenan Pepper 03:08, 19 June 2006 (UTC)

Keep in mind that what is sold in the store as "arrowroot flour" is often not real arrowroot (see note in that article). 128.197.81.181 18:41, 19 June 2006 (UTC)

Is the Wikipedia being censored by the academic guild?

This may seem like a rare problem but I have noticed that some scientific and technical articles are being edited to prevent other users from obtaining a complete and full comprehension of a topic in the same manner as a member of a trade or artisan guild might try to hide techniques or methods or understanding of what the topic actually involves. Such articles are only permitted to have a highly technical version or explanation of the process being presented in the same manner as a tradesman or artisan might withhold simple explanations from a patron for the sole purpose of mystifying the topic and keeping the patron from knowing “too much.” What is the Wikipedia policy on such behavior where simple and accurate explanations are continuously deleted from an article on the false pretense that the article is not about the example although the example fully clarifies the topic? ...IMHO (Talk) 04:36, 19 June 2006 (UTC)

Examples?

Yes, I'd like to see an example too. Of course there's a lot of information difficult for "outsiders" to understand in the 'pedia, but generally it's because of the persons lack of concern for readers with a very low level of understanding. Nothing of what I have seen suggests censorship.  freshofftheufoΓΛĿЌ  04:59, 19 June 2006 (UTC)

I would hope not but then suppose all sysops were also members of the telecom brotherhood or union and certain accurate but simplified technical disclosures were routinely deleted? Would this not make you a bit suspicous? As for examples. Put the Half-life article on your watch list and see over a period of time what conclusion you might reach. ...IMHO (Talk) 05:23, 19 June 2006 (UTC)

I'd say sometimes the medical articles are written in unnecessarily technical language. But I think this is just health professionals failing to consider their audience when writing here rather than a deliberate attempt to obscure. See Hanlon's Razor. There's also the fact that writing both accessibly and accurately about technical is a very difficult skill.

I understand the difficulty for any individual to step far enough away from the field of expertise to see it clearly form a layman's pov but that is why we participate in the Wikipedia in the first place. My concern is that when such experts guard an article with such jealously that any user who is able to bridge the gap between the experts and the layman is prevented from adding simple but accurate explanations. ...IMHO (Talk) 06:30, 19 June 2006 (UTC)

I do think there's scope for stronger attention to be paid to Wikipedia:Explain jargon.--Robert Merkel 05:31, 19 June 2006 (UTC)

In this regard you must unfortunately include mathematical symbols and representations which more often than not require examples of computer code and data in order that the jargon be explained. ...IMHO (Talk) 06:33, 19 June 2006 (UTC)

To have coordinated censorship you'd need coordination among academics in the first place. Which generally does not exist. But as a form of systemic bias, I think it is true that sometimes certain lesser-known topics get monopolized by those who know a lot about them but are not good at explaining it. The better known a topic is, the less likely this can last for long. But there are some articles which reflect a total lack of consideration for the layman (even something as non-technical and narrative-based as our biography of Franz Boas, which is about 3X too long, suffers from this). --Fastfission 13:54, 19 June 2006 (UTC)

I think that in many cases, the technical jargon is used because it saves time--it describes something specific in a way that is easily recognized by people in the field, while using a minimum amount of language. The challenge for Wikipedia, or any widely-used reference source, is how satisfy both "expert" users as well as the public at large. Experts don't want to plod through simplified explanations of what they already know; novices don't want to be frustrated by language they don't understand.

Going back to your question, I believe that there's a policy or guideline or something about how Wikipedia editors should not act as if they "own" a given article. Wikipedia is about reaching consensus and allowing many people to do their bit towards improving an article. --Tachikoma 14:06, 19 June 2006 (UTC)

The problem with reaching consensus is that there is a small group of committed academics who jealously guards some articles, immediately removing any attempt to make them accessible to the general public (which, while far more numerous, lacks the same level of commitment and is thus easily scared off by such actions). The only way I was able to find around this problem was to create a separate article for laymen. For example, the article Boolean algebra suffered from this problem, so I created the simplified version as Boolean logic, and added dabs at the top of each, pointing to the other. StuRat 17:11, 19 June 2006 (UTC)

Yes this possible solution occurred to me as well so I did the same thing and avoided even the temptation of putting a link to the new article in the existing article's "See also" section. Perhaps this way the new article will not be found and deleted before it has gained a few edits from other users who can help fight those who are unsympathetic with the needs of the layman and sometimes experts alike The real scare is that the person standing guard over the article I am concerned about has a false concept of the subject matter. Perhaps it is just as well that a new article be created to give everyone an opportunity to know the truth about the topic. ...IMHO (Talk) 19:43, 19 June 2006 (UTC)

First patented form of life...

Hi! The following question is a product of my 'momentary inattentiveness' in class(please don't avoid answering for punishing me).

What is the first 'patented form of life'? I'm quite sure, I heard the name of a scientist- Ananda Mohan Chakrabarty, in this connection(though I doubt its authenticity). How far Super Bug is related to this? Thanks,--Pupunwiki 07:51, 19 June 2006 (UTC)

hi! The first "patented form of life" was invented by the scientist CHAKRABARTY which are nothing but the OIL EATING BACTERIA.... Oil Eating Bacteria are chiefly used to clear oil spills in the process of BIOREMEDIATION In the year 1980 Chakrabarty discovered a bacteria[SUPERBUG] that could digest crude oil. SUPER BUG is said to be a strain of bacteria that is resistant to all antibiotics. It is also said to be a strain that is accidentally imported into florida from the Middle East then spread to California where it is a very serious pest feeding on almost all vegetable crops and poinsettias eg;- Bemisia tabaci, poinsettia strain some oil eating bacteria are also resistant to antibiotics...in this way super bugs are related to oil eating bacteria The oil eating bacteria Pseudomonas species is one such example for a super bug[resistant to antibiotics] --hima 10:27, 19 June 2006 (UTC)

   Thanks a lot, Hima, for clearing my doubts.
                                   --Pupunwiki 10:41, 19 June 2006 (UTC)

Well, the Diamond v. Chakrabarty resulted in the first patent for genetically modified life. But the Plant Patent Act of 1930 allows for the patenting of asexually produced cultivars, which are also "life", technically speaking. --Fastfission 13:47, 19 June 2006 (UTC)

Ridiculous Information from Wikipedia.

well, i was surfing the "war portal" on wikipedia recently. One of the articles had this link : "http://uncyclopedia.org/wiki/Palestine", under its "external links" section. And i was shocked to visit the link and the contents. And i think that site itself is open for editing, but the content still is shocking. And they have not even deleted it. Can someone help?

Uncyclopedia is in no way affiliated with Wikipedia, the site looks similar beacause they use the same software (and because they are a conscious parody site of Wikipedia). We have no influence on the content of articles on uncyclopedia, if you think their Palestine article is crossing the line of good taste, it's best to take your concerns there. Now, whether or not an external link to an uncyclopedia article is appropriate for a Wikipedia article is another matter...where did you find the link? -- Ferkelparade π 10:04, 19 June 2006 (UTC)

Thank god they don't have a reference desk. Yet. Where is this link? Wikipedia articles shouldn't link to Unencyclopedia (unless they're discussing a topic such as parody). --Shantavira 12:22, 19 June 2006 (UTC)

I read somewhere (maybe in the uncyclopedia) that it was purchased by Wikimedia. Since you can't edit articles who writes them? ...IMHO (Talk) 13:59, 19 June 2006 (UTC)

Uncyclopedia uses MediaWiki software, like Wikipedia. They are not "owned" by the same people. You can edit articles there, just like here - anyone can. What the above poster meant is that the editors here are not responsible for content there, as the majority of users do not overlap between the two sites. -Goldom ‽‽‽ ⁂ 14:32, 19 June 2006 (UTC)

It's a great outlet when you feel like posting nonsense, though! (As long as you keep it funny.) Melchoir 19:27, 19 June 2006 (UTC)

Well you can edit some things but not the majority of things in line with the idea of a contra-wiki. If you could edit everyting then it might actually serve the role of a parody where Wikipedia users could vent steam but as is its more like a spoof than a parody. ...IMHO (Talk) 19:33, 19 June 2006 (UTC)

Wavefunction, quantum mechanics, electrons etc

Quote from wavefunction -

"The complex square of the wavefunction, $|\psi |^{2}\,$, is interpreted as the probability density associated with the particle's position"

I was thinking in terms of an electron though I imagine the specific case is unimportant - my question is - Is there any reasoning or justification behind this relationship, (it seems to be a theorectical assumption used in a model) - and additionally, who originally came up with this idea and are they still alive and sufficiently sentient to be asked how/why they came up with this relationship?HappyVR 14:19, 19 June 2006 (UTC)

(disclaimer: not a physicist) Could you maybe clarify the question? Are you asking why is the complex square not simply a part of the wavefunction so that it evaluates directly to a probability? If so, this is far from a perfect answer, but it is one perspective: consider variance and standard deviation from statistics. Mathematically, variance is the simpler value, in a sense, but its units aren't the same as the original data, they are the square of those units, so the standard deviation is often used, which is simply the square root of the variance, and thus in the same units as the data. Now I'm not saying that's the real answer to your question, I'm just saying sometimes the mathematically easy quantity and the intuitively simple quantity are not the same. A better answer might be that photons/electrons/etc act like complex numbers in a sense (i.e. they follow the same rules when looked at in the right light) and it works out that once you have the complex "amplitude" for an event worked out you can square it and find the actual probability for that event. But perhaps I've only restated your question and added nothing... 128.197.81.181 18:56, 19 June 2006 (UTC)

As Probability amplitude says, this interpretation is due to Max Born who is long dead; he eventually got a Nobel for it though. Melchoir 19:24, 19 June 2006 (UTC)

Appropriate Waste Disposal

I have an old computer that I failed to fix. I've salvaged some components but I don't know if the motherboard works properly. It used to run on a 112 W PSU and has no AGP slots (just three PCI and some weird stubby slot). Should I just chuck the mobo and processor in the electrical waste at the tip? Should I keep the processor or PSU? What should I do with the case? Can't it be melted and used in something? There aren't enough provisions for people who want to be environmentally friendly... --Username132 (talk) 14:27, 19 June 2006 (UTC)

You can reuse the case. As for the rest, have you considered an art project? HighInBC 14:32, 19 June 2006 (UTC)

You are correct that computer parts may contain nasty stuff that you don't want ending up in landfill. The best bet is to contant your local recycling company and ask if they have a place to take it. (If your city picks up recycling, ask them, or if not, just another local company). Places like Office Depot often take in things like used-up rechargable batteries for recycling, but I doubt they'd have room to take whole MBs. -Goldom ‽‽‽ ⁂ 14:36, 19 June 2006 (UTC)

The plastic case is probably just that plastic plus some filler - maybe you could put that in any plastic recycling bin you can find. The processor is mostly inert - might contain some gold though but not much - the case will be ceramic or a resin. As far as I know its the glass fibre and the resins gluing it together and the lead used in soldering on the motherboard that are supposed to contain the nasties - no idea what you are supposed to do with this though - burning it is the way to release the chemicals enviromentalist don't like. The PSU contains sufficient scrap metal to be worth at least 50p to a scrap metal merchant - that's most of what I can say to help. (Art project is good idea - maybe you could use the processor as a coaster for small tots of rum)HappyVR 14:38, 19 June 2006 (UTC)

Can medium format (120) film be developed by my local pharmacy?

Is it likely that the neighborhood drugstore would be equipped to develop 120 film? Javguerre 15:28, 19 June 2006 (UTC)

No. It is likely that your local drugstore sends all film to a processing service. It is probably easiest if you just call or visit the drugstore to ask; however you might be better served by searching for a nearby camera store (not a chain like Ritz or its siblings) and asking them for advice. --LarryMac 16:11, 19 June 2006 (UTC)

The Moon

From what points on the Earth does the moon apear largest? Thanks, Lucy Hallam

The Moon would be closest to an Earth-bound observer on Mount Everest, but that's only a 9 km difference versus a sea-level observer. By comparison, the Moon's orbit causes it to vary in distance from the Earth by 40,000 km. So actual size from earth doesn't appreciably vary no matter where you are.

However, there is a well-known Moon illusion where the Moon appears largest near the horizon, though it's simply a trick of the brain's interpretation of the image, not the actual size of the Moon itself. — Lomn | Talk 16:05, 19 June 2006 (UTC)

Fish question

What is the name of this fish? It lives deep in the ocean where there is no light. It has an extendor over its eyes that has a bulbuous attachment that glows. It was used in Disney's movie Nemo.

Maybe today you are in luck since this came up on another talk page I was reading - is it Black seadevil - it sounds v. similar.HappyVR 17:12, 19 June 2006 (UTC)

and AnglerfishHappyVR 17:13, 19 June 2006 (UTC)

How much did Apollo 11 cost?

Good afternoon,

Does anyone know how much the first manned mission to land on the moon, Apollo 11, cost?

Thankyou,

Neil

Neil, is your family name Armstrong?

http://www.seds.org/spaceviews/9607/articles.html

TOTAL COST PER APOLLO MISSION:
-----------------------------
              Year   ($M)   (94$M)
Apollo 7      1968   $145    $575
Apollo 8      1968   $310  $1,230
Apollo 9      1969   $340  $1,303
Apollo 10     1969   $350  $1,341
Apollo 11     1969   $355  $1,360
Apollo 12     1970   $375  $1,389
Apollo 13     1970   $375  $1,389
Apollo 14     1971   $400  $1,421
Apollo 15     1971   $445  $1,581
Apollo 16     1972   $445  $1,519
Apollo 17     1972   $450  $1,536
---------------------------------
                   $3,990 $14,644

Have a nice afternoon. -- Toytoy 17:37, 19 June 2006 (UTC)

Thank you very much for your help; no my surname isn't Armstrong I'm afraid!

Thanks,

Neil

Edibility of Cucumis melo leaves

Many cucurbits have edible leaves, but I have not been able to satisfy myself about Cucumis melo. I was surprised at how little information I could find for such a well-studied plant. BioNatural claims that the Pedi and the Sukuma people eat the leaves as a "potherb and relish", but the mention is off-hand and undetailed, and the company sells herbal extracts, so they may have a profit motive in giving this information. An agricultural researcher in Uganda lists the leaf among the plant's edible parts, but again no detail is given. Cucumis melo is not on Leaf for Life's very long list of plant species that have reportedly been eaten by people. Plants for a future reports that "the sprouting seed produces a toxic substance in its embryo", but not what the toxic substance is, where in the plant it is distributed, nor how long it persists as the plant grows.

I have added Cucumis melo to the list of plants with edible leaves, but have not eaten the leaves of the melon vines in my garden. Any further information would be appreciated. Thank you. Leafeater 17:53, 19 June 2006 (UTC)

EMP nullification

What is the name of the device that nullifies the effect of an electromagnetic pulse on electronic devices? It resembles a cage made of wire. I tried a number of searches under different topics and come up empty. It's driving me crazy. —The preceding unsigned comment was added by 72.54.24.94 (talk • contribs) 19:39, 19 June 2006 UTC.

I'll put you out of your misery. See Faraday cage. --GraemeL ^(talk) 18:43, 19 June 2006 (UTC)

Thanks much. Now I can sleep at night.

JPG image problem

I have a group of jpg images which were scanned into the computer under Windows 98 using an HP Scanjet IIcx flatbed scanner. The images seem to be okay except that their widths have been compressed to about 1/3 of the left side of the page with the remainder of the page being solid black. I have never seen this before. Does anyone know what caused this and more importantly how to restore the width of the image without loss of information? Thanks. ...IMHO (Talk) 19:04, 19 June 2006 (UTC)

Orbit/gravity/weightlessness

I have a question relating to gravity/orbits, etc. Do you know who I can direct it to?

I understand that objects/people in orbit around the earth only appear weightless due to the fact that they are in freefall, and since the spacecraft and everything/everyone aboard are all falling at the same rate of speed around the earth (in orbit), they appear to be weightless.

My question is this:

When the astronauts travelled to the moon, they also experienced weightlessness. Since they left earth orbit on the journey to the moon, and were not in freefall, why were they weightless en route?

Jake Whalen

You should probably check out our article on weightlessness, particularly the discussion on pressure gradients. As a layman, though, here's my attempt:

Weightless freefall isn't dependent on "falling" per se but rather on you and your reference frame (that is, the spacecraft) not resisting gravitational forces, whether or not those forces will eventually cause you to collide with the relevant astronomical body. When you consider "falling" as instead being "coasting without support", weightlessness between the Earth and Moon makes a good bit more sense (to me, at least).

Also, it's a good idea not to post your phone number on the internet. — Lomn | Talk 20:02, 19 June 2006 (UTC)

Symptoms of long-term oxygen deprivation

What are some possible symptoms of shallow breathing, or mild long-term oxygen deprivation? For instance, someone contracts sleep apnea in conjunction with asthma and allergies, causing generalized shallow breathing and low oxygen intake.

Centrifigal Force and Gravity

Since a object on the equator is spinning faster then one on the pole, shouldn't there be a difference in weight between them? Wizrdwarts (T|C|E) 21:19, 19 June 2006 (UTC)

Yep, and there is. See Gravity (Earth) and Apparent weight. moink 21:28, 19 June 2006 (UTC)

Why is AC current prefered over DC?

I've read about the subject, but I have never found a conclusive answer. There must be a major reason, otherwise we would still have both systems. Which reason is that? Afonso Silva 21:20, 19 June 2006 (UTC)

DC power supplies require a power station to be built every fifty miles or so, which becomes very impractical outside large cities. As a result, AC current is used; see the War of Currents article. Andromeda321 21:34, 19 June 2006 (UTC)