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December 21

vasaline

if you all can tell me how hot and long vasaline burns, that would be great. thank you. — Preceding unsigned comment added by 70.114.254.43 (talk) 09:09, 21 December 2011 (UTC)

Vaseline is a type of petroleum jelly, and the article on petroleum jelly says "It is only flammable when heated to liquid, then the fumes will light, not the liquid itself, so a wick material like leaves, bark, or small twigs is needed to light petroleum jelly". In other words, you can't burn vaseline without first vaporizing it. --Colapeninsula (talk) 10:20, 21 December 2011 (UTC)

FYI, every other entry from that IP has been vandalism. ←Baseball Bugs ^{What's up, Doc?} carrots→ —Preceding undated comment added 15:23, 21 December 2011 (UTC).

I suggest you re-read wp:vandalism, as well as wikt:all. Neither [1] nor [2] appear to be overt vandalism. Buddy431 (talk) 00:17, 22 December 2011 (UTC)

You're right, some of them aren't overt vandalism, but merely trolling. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:37, 22 December 2011 (UTC)

To actually answer the question, we have the article Adiabatic flame temperature. Vaseline is a hydrocarbon mixture distilled from petroleum, similar to kerosene or Fuel oil, though a bit heavier. These all have adiabatic flame temperatures of about 2100 ^oC, so I would bet Vaseline is similar. Buddy431 (talk) 00:17, 22 December 2011 (UTC)

How many muscles are there in the ears?

I would like to know how many muscles are there in the ear? — Preceding unsigned comment added by 77.125.22.128 (talk) 12:16, 21 December 2011 (UTC)

Our article would imply there are none... is that right? I'd love a second opinion though. --Ouro (blah blah) 13:22, 21 December 2011 (UTC)

However, the Muscles of auditory ossicles are in the middle ear. --Ouro (blah blah) 13:28, 21 December 2011 (UTC)

And there are the Auricular_muscles... and that should be it! --Ouro (blah blah) 13:30, 21 December 2011 (UTC)

I've seen people wiggle their ears as a party trick. That would require muscles. HiLo48 (talk) 17:13, 21 December 2011 (UTC)

There aren't any muscles in human fingers, either, yet people seem to be able to wiggle those as well. The muscles that control the fingers are in the hand and forarm, and they pull on tendons, etc. which are attached to the fingers. People wiggle their ears similarly, using muscles outside of the ear to pull on tissues that are attached to the ears. —Akrabbim^talk 18:00, 21 December 2011 (UTC)

Hey! I've got arrector pili muscles in my fingers. How about you? (please ignore this as it is off topic if you don't know what arrector pili muscles are) -- kainaw™ 18:30, 21 December 2011 (UTC)

Interesting...are these present on ears as well? I do have some fuzz on my ears, but I'm guessing that not all follicles have these things. —Akrabbim^talk 19:05, 21 December 2011 (UTC)

Depends, do you get goosebumps on your ears? --Jayron32 19:17, 21 December 2011 (UTC)

I work one floor above dermatology and see those docs when go get a coke. According to one of them, the hairs inside your ears and nose do not have muscles. He didn't know about hair on the outside of the ear and didn't seem too interested in finding out. -- kainaw™ 19:12, 21 December 2011 (UTC)

One floor above dermatology? That must be the Epidermatology Department.  :) -- Jack of Oz ^{[your turn]} 03:35, 22 December 2011 (UTC)

ha! DMacks (talk) 16:49, 22 December 2011 (UTC)

So, how many muscles are there? — Preceding unsigned comment added by 77.125.22.128 (talk) 17:02, 22 December 2011 (UTC)

It looks like Ouro did a good job, though arguably some other muscles attached to the Eustachian tube (see article for list) should count. But there's the problem... despite its obviousness, the definition of the human ear isn't entirely clear. Do these, or those outer auricular muscles, actually count? How about the vestigial ear muscles (see ear) that don't visibly move anything? That's the thing about biology - it tends to resist efforts to come up with easy numbers and simple lists. Wnt (talk) 17:15, 26 December 2011 (UTC)

boiling point of blood

Recently, a small article appeared in the Press regarding an interview with scientist/daredevil Kittinger who dropped out of a helium balloon capsule from the edge of space and lived to tell about it. Now tell me this. The interview mentions that at 62000 feet, blood boils It's obviously not because heat is applied to it but, I suppose, only because of the reduced pressure on every molecule of his body. Hence, at sea level, one's blood is at the much increased pressure of all that column of air above that person. What would happen then to his blood, were he to sink down into a, say, 2, 3, 5, 10 mile hole in the ground, assuming he does not encounter a column of lava on its way up to the caldera of some volcano? — Preceding unsigned comment added by 67.59.198.29 (talk) 18:17, 21 December 2011 (UTC)

You are basically asking about deep diving. The main concern is nitrogen narcosis. -- kainaw™ 18:25, 21 December 2011 (UTC)

No, that's for going under water with pressurized air.

He's asking about going down a vertical hole in the ground, so that you have a higher column air on top of you. --Enric Naval (talk) 21:18, 21 December 2011 (UTC)

Deep diving is not scuba diving. Deep diving involves holding your breath and seeing how far down you can go. The limitation used to be about how long you could hold your breath. Now, it is a problem with pressure on the blood causing the divers to act as if they are drunk and, sometimes, do things that endanger their lives - like start breathing. -- kainaw™ 21:22, 21 December 2011 (UTC)

You are confusing deep diving with free-diving, particularly competitive apnea. -- ToE 23:38, 24 December 2011 (UTC)

Wow, now that's an interesting risk sport.

I wonder if we would get the same effect when going deep inside a vertical hole in the ground. Would get air pressures much higher than 1 atmosphere, and start getting drunk? Someone should research that and sell tickets, surely lots of people would want to try it. --Enric Naval (talk) 21:50, 21 December 2011 (UTC)

The deepest dives are under 300m (about 0.2 miles). The questioner asked about going over 2 miles down a hole. I do not know, but I assume that air pressure builds up as you go multiple miles below the ground just as going far less than a mile below the water. I also have a gut feeling that the mammalian dive reflex won't kick in without being in water - which will greatly reduce how well the circulatory system reacts to increased pressure. -- kainaw™ 21:56, 21 December 2011 (UTC)

Looking at spelunking records, the records keep hitting around 1 mile below sea level. The caves go further down. I do not know why the records hang around that level. Is is pressure? Is it that the caves get to small to go further? Is it the heat from being so far down? -- kainaw™ 22:00, 21 December 2011 (UTC)

The Kennedy gold mine went to a depth of 5,912 feet which is over a mile (5,280ft). I assume miners worked a the bottom. Did they have special gear? Bielle (talk) 22:05, 21 December 2011 (UTC)

That is the depth of the cave, not the depth below sea level. It is only about 4,700 feet below sea level, which is less than a mile. -- kainaw™ 13:48, 22 December 2011 (UTC)

The TauTona Mine is some 2.5m deep apparently. this video (http://www.youtube.com/watch?v=lK3IUz80k9U) doesn't seem to show any special equipment though it's not clear how far down he ends up going (I think it mentions 3,000m which would be close to 2 miles down).ny156uk (talk) 22:18, 21 December 2011 (UTC)

Note that the reason you can go so much further down in an air shaft than a water-filled shaft is the much lower density of air, which means the pressure builds up far more gradually, due to less mass above you. Subsequently, I wouldn't expect any problems beyond your ears popping (if you go up or down too quickly), for any mine depth we can achieve.

As for blood boiling at low pressures, I'd expect it would boil at about the same pressure/temperature combos as water, although blood inside the human body is likely to be at higher pressure than blood in a pail, in your scenario, since the skin doesn't expand as easily as a balloon. And well before your blood starts to boil, I'd expect it to burst out of the alveoli in the lungs and for you to die from drowning in your own blood. StuRat (talk) 23:03, 21 December 2011 (UTC)

The person discussed is Joseph Kittinger who jumped from 102,800 feet (31,300 m) in a pressurized suit. His glove malfunctioned. Rmhermen (talk) 23:22, 21 December 2011 (UTC)

Should we expect the formula for Atmospheric pressure#Altitude atmospheric pressure variation

$p=p_{0}\cdot \left(1-{\frac {L\cdot h}{T_{0}}}\right)^{\frac {g\cdot M}{R\cdot L}}$

to apply for negative values of h? -- ToE 23:32, 21 December 2011 (UTC)

It applies for values of h that are small relative to the Earth's radius (the strength of gravity changes as you go deeper, first rising (the mass loss from being below the crust is outweighed by the r^2 increase from being closer to the high-density core), then falling, but you can ignore that as long as you stay near the surface). I get a depth of 6800 meters to double the atmospheric pressure. --Carnildo (talk) 00:47, 22 December 2011 (UTC)

In water you'd only have to go about 7-8ft (less than 3 meters) to double the pressure on your body. So all the strange effects that happen when you dive too deep are just about impossible in air.Tobyc75 (talk) 18:12, 22 December 2011 (UTC)

Those numbers (7-8ft) are way off. A rule of thumb used by divers is that, underwater, the pressure increases one atmosphere with each 10 meters or 33 feet of depth. Moreover, if the formula above is valid for the range of negative values of h suggested by the OP, then at 10 miles (16 km) down the pressure will be 5.1 atm absolute or 4.1 atm gauge, corresponding to a diving depth of 40 m which, these days, is considered by most agencies to be the absolute recreational dive limit. There would be no immediate physiological concerns on the level of "boiling blood". The big concern for technical divers breathing air at great depth is oxygen toxicity, and the NOAA diving manual considers 218 ft (66.4m) to be the absolute maximum depth on air, regardless of bottom time. (Beyond that, other gas mixes must be used.) 65 m depth yields 7.5 atm absolute, so the OP will have to extend the hole down to 20.7 km or nearly 13 miles to experience that pressure. My concern with the applicability of this formula was not a varying g, but whether the adiabatic lapse rate of 0.0065 K/m would continue to hold. If so, then pressure might be the least of your concerns, as 20 km down the air temperature will be 130 K greater than at the surface. Fortunately, the vapor pressure of water is only 4.66 atm at 150 °C, so while the temperature may not be conducive to good health, at least your blood won't boil. -- ToE 00:41, 24 December 2011 (UTC)

Size and cats

I've spent a while reading up various articles, but my basic question remains unanswered--why is there so much more size variation in domestic dogs than domestic cats? Why aren't there any cat breeds the approximate size of a St. Bernard or Great Dane? It looks like the Maine Coon is the largest domestic cat breed, but even that tops out around 25 pounds. I would assume that selective breeding could create larger cats, so why hasn't it happened? And why has it happened for dogs? Meelar (talk) 23:39, 21 December 2011 (UTC)

My impression is that selective breeding hasn't made dogs much larger than their ancestors - dogs are thought to have been domesticated from the Gray wolf, with the larger varieties pretty on par with larger dog species. Dogs have been selectively bred much smaller in some cases. Housecats are thought to have perhaps been domesticated from the Wildcat, again, on par with most species. I'm not sure if this is relevant (are there any very small domesticated cat breeds?), but it's interesting. Buddy431 (talk) 23:49, 21 December 2011 (UTC)

Yes, interesting. There are two factors that I can think of. One is that dogs have been domesticated much longer than cats. We simply had more time to breed them. The other is that humans had good reasons to breed smaller dogs (adult gray wolves reach 100 lbs and require a lot of food - sometimes a smaller dog may be more convenient), as well as to breed dogs in general (to adapt to different tasks (tracking wild animals while hunting, guarding settlements, herding sheep, pulling sleds, etc), whereas cats were always used for a singular purpose - to catch mice.--Itinerant1 (talk) 00:01, 22 December 2011 (UTC)

The Irish Wolfhound is an extremely ancient breed of dog, and the whole point of it is to be bigger than a wolf. (In fact I think it's my favourite prehistoric invention. We'll fight off the wolves ... by turning some of them into bigger, friendly wolves.)  Card Zero  (talk) 08:18, 22 December 2011 (UTC)

the obvious answer is that despite the cultural willingness to lump cats and dogs together into a sort of pair, they are wholly distinct species and cannot be directly compared. That the canine has been bred into such an extensive physical variety has no relationship whatsoever with the potential for felines to achieve the same. I have no references, but wished to correct your flawed original (though unstated) assumption. I'm sure someone will be along shortly to confirm with good sources. The Masked Booby (talk) 23:53, 21 December 2011 (UTC)

While dogs have been bred for many different tasks, which require different body types, cats have not. The only two purposes for cats I can think of are small rodent control and as pets. Since the same body type is appropriate for both of these roles, and matches their original body type, very little breeding was required. Only recently have people begun to breed both cats and dogs for "show". That is, to exaggerate some features and minimize others. This may eventually result in tiny cats and huge cats, just as it did for dogs, when they were bred to be tiny and huge. StuRat (talk) 23:57, 21 December 2011 (UTC)

Per Cat#Domesticated_varieties, cats have only been selectively bred for like 150 years or so. Cats have only been domesticated, as in raised specifically by humans, for only about 9,500 years. Given that short time period, there hasn't been much time to develop widely distinctive breeds. By comparison, Dogs have been domesticated for over 15,000 years, and per Dog breeding, the appearence of distinctive dog breeds is prehistoric, so they're have been several thousand years over which distinctive breeds have been developed. More time = more variation. --Jayron32 00:01, 22 December 2011 (UTC)

Restrictions on size get more complicated when you look at entire families. Domesticated dogs range from chihuahuas up to wolfhounds whereas domesticated cats run all around the same size. However, the biggest dog is about as big as the biggest wolf or any other canid; basically, we seem to breed them as big as that family can get. The feline family, however, covers a much larger range. The smallest housecat is only slightly bigger than the smallest breed of dog, but the biggest cats (tigers) are much, much, larger than even the biggest canine. So which group has the largest variation? Even weirder, the cat family is much more homogenous in terms of body plan than what we've managed to tease out of the canine one, so despite being "limited", the feline body plan seems to scale up better than the canine one. Who knows what kind of weirdness we might have gotten out of the felines if we';d been mucking with them for 10,000 years? Matt Deres (talk) 15:39, 22 December 2011 (UTC)

I don't think this is an actual reason they haven't been bred uber large, and I don't want to get cat lovers in a huff but, on average, if you bred 300, 300 lb healthy dogs and gave them to 300 owners who would treat them well, and 300, 300 lb healthy housecats and gave them to 300 owners who would treat them well, at the end of five years you'd have 300 happy dog owners and 250 terrified cat owners (the other 50 being dead).--Fuhghettaboutit (talk) 01:01, 23 December 2011 (UTC)

I disagree. I'd say both cats and dogs that large would be dangerous. Even much smaller dogs, like pit bulls, manage to kill people. StuRat (talk) 23:04, 23 December 2011 (UTC)

Of course there are far less stable breeds but even among the most unstable, very, very few people are killed by their own dogs attacking them. More on point, it's an extremely rare event for an unabused dog to attack it's own owner at all, and among stable breeds, you would need to look at the population in millions to find examples. On the other hand, despite that there are cats that are very loving, it is not uncommon at all for a cat to get a bit riled and claw you. There's no comparison.--Fuhghettaboutit (talk) 01:04, 24 December 2011 (UTC)

Dogs bite millions of people each year. Whether the people bitten are their owners doesn't seem particularly relevant to whether they are dangerous, or not. StuRat (talk) 06:45, 25 December 2011 (UTC)

As you have correctly stated, the largest breed of domestic cat is the Maine Coon. The smallest is the Singapura. The smallest breed of dog is the Chihuahua. As others have stated, cats are far less advanced in domestication than dogs are. Next up in line, size-wise, after the domestic cat (and their counterpart, the Wildcat) would probably be the Lynx. They don't make good pets, as they usually become aggressive at maturity. Does anyone feel like selectively breeding them for tameness? It'd be cool to have them as pets, and they're endangered, so it might help guarantee the species' survival in captivity. Takers? 58.111.186.225 (talk) 18:31, 25 December 2011 (UTC)

This link [3] from our feral cat article has a feral cat shot in Australia 91 cm calculated long or about 170 cm calculated from head to tip of tail compared to the largest domestic cat about 122 cm long from head to tip of tail. Scientists mistakenly believe that feral cats were introduced by Europeans and escaped but Aborigines report that cats arrived in Australia 500 years ago. The so-called feral cats have been breeding in the wild of Australia for 500 years and were larger than domestic cats when European colonists first arrived.
Sleigh (talk) 19:08, 25 December 2011 (UTC)

Re-read my premise. Large dogs being dangerous or not has nothing to do with what I said.--Fuhghettaboutit (talk) 04:13, 26 December 2011 (UTC)

I like the arguments here. The gist seems to be: it's easier to train dogs than cats, so people designed breeds to do a wider variety of tasks, some of which involved quite large or quite small physical size. Wnt (talk) 17:18, 26 December 2011 (UTC)

And dogs are easier to train because dogs/wolves naturally have a pack structure, with the alpha male and alpha female calling the shots. So, it's not that hard for humans to take on that roll, and get their pack to do as they're told. StuRat (talk) 17:43, 26 December 2011 (UTC)

December 22

Contact lenses

hello. Can people who wear contact lenses go longer without blinking? Since the lens keeps the cornea, iris and pupil covered the film that forms on the eye usually does not form on these most sensitive parts, correct? I've never worn contacts, but this is something I've always been curious about. Thanks. 24.92.85.35 (talk) 00:50, 22 December 2011 (UTC)

I wear contacts and I've never noticed anything like this, fwiw. Also, removing film from the eye is only one function of blinking; according to our article, it's also important for spreading tears evenly across the surface of the eye. So there shouldn't be any less need for blinking among contact wearers. Meelar (talk) 00:58, 22 December 2011 (UTC)

Agreed. Since water evaporates just as quickly from contact lenses as from the eye, you need to blink just as often to replenish it. (I'm talking about soft contact lenses, which are water permeable. The old hard contacts might be different.) StuRat (talk) 02:00, 22 December 2011 (UTC)

Yes; I used to suffer from sore eyes after a day in an air-conditioned office. My optician advised me to increase my "blink rate". I just went back to glasses. Alansplodge (talk) 15:50, 24 December 2011 (UTC)

Nose blowing

Do children inherently know how to blow their nose when it is plugged or does the skill have to be taught? Thanks, CBHA (talk) 01:58, 22 December 2011 (UTC)

WP:OR here, but my kids had to be taught to do it. --Jayron32 05:09, 22 December 2011 (UTC)

Instinct seems to favor wiping their nose of their sleeves or sucking it back in, for liquid snot, and picking their nose and wiping it on anything handy, for boogers. StuRat (talk) 06:27, 22 December 2011 (UTC)

On a tangent, I wonder if anyone has tried to explain why picking your nose is such a pleasure? After all, it can damage the mucous membranes and make you more susceptible to disease (or that's what they tell me). The same goes for picking at scabs.--Rallette (talk) 07:34, 22 December 2011 (UTC)

Trichotillomania. This isn't really an explanation, but it seems relevant. Oh wait, dermatillomania is more on target. It's all much the same thing, anyway. I like the second link better because it mentions it as (yet another thing) affected by dopamine. Delusional parasitosis is also related. On a more cheerful note, nose-picking mentions the theory that picking your nose and eating it is good for the immune system.  Card Zero  (talk) 09:00, 22 December 2011 (UTC)

Before the invention of handkerchiefs, there wouldn't really be any point to blowing your nose - it would just be even messier than the approaches StuRat mentions, and wiping your nose with the kind of coarse fabrics that used to be used wouldn't be pleasant. I doubt there's any nose-blowing instinct. Smurrayinchester 08:49, 22 December 2011 (UTC)

I remember reading that blowing your nose forcefully when you have a cold may make the cold worse. The only evidence I can find for this now is a brief mention from the New Scientist [4] which has a broken link to an abstract. I seem to remember the research involved pumping fake snot into people's nasal passages, and won an Ig Nobel prize.  Card Zero  (talk) 09:23, 22 December 2011 (UTC)

You can blow your nose onto the ground if you're skilled. I've seen professional sportspeople do it.

(As an aside, I wonder if there is a human instinct to remove material stuck to the body, which would apply to scab picking and nose picking, as well as to getting rid of insects on your skin, washing, etc.) --Colapeninsula (talk) 10:09, 22 December 2011 (UTC)

Well, define instinct. Since drugs can turn the urge on or off (see my links above), it looks pretty low-level. Then again, drugs can make you loquacious or silent, and it would be a mistake to conclude that languages are therefore instinctive, so I guess the specifics of skin-picking might be cultural too. I'd say there's an instinct that tends to manifest as picking at various things on the body. I never knew nose-blowing was a professional sport. People are so competitive.  Card Zero  (talk) 10:44, 22 December 2011 (UTC)

If you're skilled, you can blow your nose into the trashcan. I can easily lean over and shoot snot out either nostril and right into the trashcan by my desk. As for skill, I've been doing it for over 30 years, so I've had a lot of practice. I prefer it to using a tissue because it doesn't cause irritation around the nose, but I avoid doing it if I'm not the only person in my office. -- kainaw™ 18:19, 22 December 2011 (UTC)

Aussies call that technique the bushman's hanky. Vespine (talk) 00:34, 23 December 2011 (UTC)

Quelle etiquette. Alansplodge (talk) 15:48, 24 December 2011 (UTC)

I'd tend to say that nose blowing is a variation on the very natural phenomenon of sneezing, which is of course experienced by many species, not just humans. Regardless I'd say nose blowing in the sense of clearing your nose of blockages would be a natural thing to do, the actual mechanism we use in typical western societies today is probably learnt, as others have suggested. --jjron (talk) 14:31, 22 December 2011 (UTC)

Incredible calculation

This TED Talk is fun, but unfortunately the most interesting part where he's showing his thoughts is limited. His amazing performance does not show what "the trick" is. It seems to have to do with a representation of numbers in words but I don't understand what he's really doing to get the right result. (Btw I happen to relate numbers to words, 9 being "blue" is pretty obvious to me, but that wouldn't doesn't help me calculating!). Does anyone have a rational explanation on what's really going in his head? Joepnl (talk) 02:05, 22 December 2011 (UTC)

See Mental calculation, in particular the Squaring numbers section. For the day-of-week calculations, see Weekday determination and Doomsday rule. Red Act (talk) 03:26, 22 December 2011 (UTC)

See also, synesthesia. Grapheme-colour synesthesia seems to be the most common form, and a part of me doesn't really believe other people don't experience this. The one that really surprised me when I read that article is temporal-spatial synesthesia, because I simply cannot imagine how else people perceive time. (It does explain why time as the fourth dimension is treated as anything other than obvious by some). 86.163.212.160 (talk) 16:21, 22 December 2011 (UTC)

I always find color synesthesia hard to image because it so clearly conflicts with the actual color information of text. I believe I as a child (and perhaps my son now) have a type of Personification as described in that article. It was obvious that to me adding two "good" numbers could never yield a "bad" number which sped up addition problems, double checking answers, determining even and odd, etc. Faster than analyzing the problem or even evaluating the numbers. But this added "moral" dimension doesn't conflict with the black (or mimeo blue) color of the number on the page. I had a college music professor who would tune us up by having us sing laser-sharp green E flat, etc. I suspect he literally saw the colors and that it improved his speed at determining the pitch. Rmhermen (talk) 17:21, 22 December 2011 (UTC)

Mimeo blue? Sure you're not thinking of a pastel dark-purplish from a spirit duplicator? DMacks (talk) 17:29, 22 December 2011 (UTC)

While purple was perhaps the most common, spirit duplicator waxes in a variety of colors were readily available—including blue. TenOfAllTrades(talk) 18:15, 22 December 2011 (UTC)

Yup. But my point is that spirit ≠ mimeo. DMacks (talk) 18:34, 22 December 2011 (UTC)

Yes, Mimeograph duplicators usually had black ink, but any colour was possible, and several were available. Dbfirs 22:25, 22 December 2011 (UTC)

In my school days, before xeroxes were in wide usage, exams and such were typically printed with a mimeograph, and they were typically in that sort of light-purple-ish color, although I recall sometimes seeing them in black instead. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:33, 23 December 2011 (UTC)

I'm glad you see E-flat as green, Rmhermen. Me too. Hence the association with forests, hunting horns and the like, and it's no coincidence that the "natural" key of the horn is E-flat. The name Richard is also green and in E-flat. No wonder Richard Greene was chosen for the title role in The Adventures of Robin Hood (TV series). -- Jack of Oz ^{[your turn]} 19:32, 22 December 2011 (UTC)

Alexander Scriabin would not have agreed.--Shirt58 (talk) 08:11, 23 December 2011 (UTC)

@ 86.163.212.160 About time: do you agree with me that "pushing back" an event, meaning to make it happen later should be "pushing forward" as it going to be further from you? Joepnl (talk) 00:50, 24 December 2011 (UTC)

Well, I'd say that you're pushing it forward in time, so yes, it has always confused me that people would call that pushing back. But at least it's pushing, which makes sense for moving something further away from you. I guess if the event is facing you, it is backing away from you? Merry Christmas! 86.164.77.59 (talk) 20:25, 25 December 2011 (UTC)

I found out what is meant by "pushing back" I guess. You have to imagine a football team, where the players are events. If one of them comes forward he's actually walking towards you. Joepnl (talk) 01:16, 27 December 2011 (UTC)

Where does the higgs boson go?

This is a three-part question (although the answer to one might answer the other two).

First question: Where does the higgs boson go on this diagram? Given that it's related to mass and mass is related to gravity, my guess is that it would go beside the gravitron, but from what I understand, the higgs boson is not a force carrier.

Second question: Why isn't the higgs boson a force carrier? From what I understand, charge is mediated by photons, so they are a force carrier, and colour is mediated by gluons, so they are a force carrier. So if mass is mediated by higgs bosons, why aren't they a force carrier?

Third question: If the answer to question #2 is that the higgs creates the mass and the gravitron mediates it, then why don't colour and charge and spin also require a seperate creator and mediator?

Thank you. —Arctic Gnome (talk • contribs) 08:30, 22 December 2011 (UTC)

Higgs does not naturally fit into that diagram. I'd draw it as a side "leg" entering into "grand unified theory". Whether it is a force carrier or not, that depends on the point of view, normally we don't look at it as a force carrier.

You could, in principle, say that Higgs is the carrier of the coupling between left-handed and right-handed particles. You could think that there's not just one particle, "the electron", but "the left-handed electron" and "the right-handed electron", and each of these are naturally massless and travel at the speed of light. But there is a coupling between the two which makes it possible for a left-handed electron to emit a virtual Higgs and to turn into a right-handed electron travelling in the opposite direction. The net effect is that the whole thing looks like a single particle, which appears to be massive and travels in a zigzag pattern at a sub-light speed.

Graviton does not couple to mass. Graviton couples to energy. Even massless particles can couple to gravitons. Higgs prevents particles from always moving at the speed of light.

I know that I'm probably confusing things rather clarifying them.--Itinerant1 (talk) 09:27, 22 December 2011 (UTC)

Gravity couples to the Stress–energy tensor which includes energy density, momentum density, energy flux, pressure, and shear stress. Mass is related to energy and momentum through the dispersion relation$E^{2}=(mc^{2})^{2}+(pc)^{2}\,$. Dauto (talk) 14:42, 22 December 2011 (UTC)

area vector

my teacher told me that area is a vector. if so then adding the surface area of a 3D cube, the opposite sides get cancelled out and resultant becomes zero vector.but mathematics says that area of a cube is 6a2. what went wrong ? mathematics?? or physics?? or me?? — Preceding unsigned comment added by Gokul cv india (talk • contribs) 08:58, 22 December 2011 (UTC)

Area can be a vector (see bivector and exterior algebra), but when you are asked for the total surface area, the answer required is a scalar equal to the sum of the magnitudes of vector areas of the six faces. Dbfirs 09:30, 22 December 2011 (UTC)

hypothyroid

homeopathy or allopathy what is the best way of treatment of hypothyroiodism ?Rikisupriyo (talk) 10:06, 22 December 2011 (UTC)

The article hypothyroidism discusses treatments, none of which involve homeopathy, so allopathy is your answer. Note that we are unable to advise you on specific treatments or offer any medical advice. --Colapeninsula (talk) 10:14, 22 December 2011 (UTC)

Recommending any particular real treatment for any particular disease, such as recommending any particular one of the treatments listed in the hypothyroidism article, would be a clear-cut violation of the reference desk's "no medical advice" policy. But homeopathy isn't even real medicine; it's just bullshit. Asking whether homeopathy or allopathy will work better for treating hypothyroidism is effectively asking whether you should ask your doctor about what to do, or just independently choose to not treat the disease at all. The answer is to ask your doctor about what to do. Red Act (talk) 15:34, 22 December 2011 (UTC)

Well stated. :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:06, 22 December 2011 (UTC)

Taste of pills

What substance makes pills taste like they taste? I suppose some specially bitter, but inert, component is added, and that placebos are not actually sugar pills. But options regarding flavor are there? 88.8.69.150 (talk) 14:48, 22 December 2011 (UTC)

The article Pharmaceutical formulation doesn't directly answer your question, but I infer from it that because the inert ingredients have to be compatible with the drug itself, they will vary depending on what the actual medicine is... and by extension, some of those ingredients might taste more bitter for some medicines than for others. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:11, 22 December 2011 (UTC)

The inert components of a pharmaceutical (excipients) are not bitter - they generally have little or no taste except that some have sweetness (some excipients are, in fact, sugars). As a broad generalization, the chemical properties that make a chemical compound "drug-like" often also cause a bitter taste, so it is typically the active pharmaceutical ingredient that is bitter. As a side note, the class of natural chemical compounds known as alkaloids have similar properties that make them both bitter in taste and the chemical inspiration for novel pharmaceuticals. — Preceding unsigned comment added by 148.177.1.210 (talk) 16:33, 22 December 2011 (UTC)

It depends a lot on what medication is involved. Capsules enclose the powdered or liquid medication in an inert material that dissolves or breaks up in water; these generally have a very neutral flavor, though in theory one could add any number of food-safe flavoring agents. Coated tablets could be similarly modified, provided that the flavoring didn't interact with the underlying drug. (In prinicple, I suppose one could manufacture a tablet with multiple layers – flavoring outside, protective coating, and active drug at the core – but this adds cost and complexity to the manufacturing process, would likely require additional safety and efficacy testing, and also makes the pill larger and therefore more difficult to swallow.)

In regular uncoated tablets, the taste will depend on the taste of the drug itself, along with the flavor of whatever binders and other agents have been added. Making drugs (especially over-the-counter drugs) less unpalatable to consumers can be an important marketing tool. To take one example, [Paracetamol]]/acetaminophen is a common drug that is inherently bitter. This paper examines modifications to the tablet manufacturing process to limit the rate at which the tablet releases paracetamol in the mouth, thereby reducing the perceived bitterness.

In preparations intended for children, flavorings are more common. By far the most common are probably children's multivitamins; the largest chunk of the market probably belongs to Flintstones Chewable Vitamins, which are available in fruit flavored chewable tablets and 'gummies'. This paper reports on taste-tests of various oral antibiotic liquids for children. Here's a grape-flavored chewable acetaminophen tablet in a children's dose. TenOfAllTrades(talk) 17:04, 22 December 2011 (UTC)

space balls!

In reference to these space balls reportedly falling for the past 20 years in Australia, Latin America, and Southern Africa, have they actually been reported? Can the reports be found? What are the theories as to the balls' origin? Do those locations on Earth line up in some special way? Thanks Adambrowne666 (talk) 22:33, 22 December 2011 (UTC)

Lots of things fall out of orbit, or off of high-altitude aircraft and rockets. I'm a subscriber to Orbital Debris Quarterly, a free newsletter from NASA's Johnson Space Center; and (almost) every issue packs an exciting new discovery of space junk landing in unusual places. (There's also a lot of coverage of space-debris that does not re-enter the atmosphere). You can sign up at http://orbitaldebris.jsc.nasa.gov and read archived issues. Nimur (talk) 23:05, 22 December 2011 (UTC)

A helium pressure tank? They are often made of titanium (that might be a novel metal in those parts of the world) and of about that size--Aspro (talk) 01:32, 23 December 2011 (UTC)

Thanks, both; have subscribed to ODQ - what a great resource. Adambrowne666 (talk) 23:19, 23 December 2011 (UTC)

December 23

Standing on a satellite

I know that astronauts and whatnot "float" around their spacecraft because they are in freefall, tumbling around the earth. If they were falling at the exact same rate, could an astronaut stand normally (albeit at a potentially reduced weight due to distance from the center of the earth) if the physical forces were lined up correctly? How about on a geosynchronous satellite? If not, what conditions would allow it? Mingmingla (talk) 01:52, 23 December 2011 (UTC)

An astronaut could "stand" on any object, so long as neither attempted to move. As soon as the astronaut stepped anywhere, or crouched, or did anything which exerted a force on the satellite, the two would fly off from each other in opposite directions (relative to their old position based on their difference in mass). In order for that not to happen, the "satelite" would have to be large enough to exert enough gravity to hold the astronaut fast. I'm not sure what size that would be, but it would be substantially larger than any object we could build and launch from earth. --Jayron32 02:02, 23 December 2011 (UTC)

The astronaut could be said to "stand" on the satellite if he can't jump fast enough to escape its gravitational pull. Assuming that the satellite is spherical and it has the same density as Earth, its escape velocity is proportional to the radius. The escape velocity of the Earth is 11 km/s, its diameter is 12700 km, jump speed is ~1 m/s, so the astronaut should be able to stand on any planetoid that is larger than ~1 km in diameter.--Itinerant1 (talk) 04:26, 23 December 2011 (UTC)

Whether a spaceship is orbiting or plummeting, you will not feel earth's gravity relative to your ship. (ie:You'll float around.)

If you were stationary compared to earth, but at a low orbital altitude, (Say, at the top of two hundred mile tall flag-pole) you would feel Earth's gravity, but somewhat reduced.

If you were stationary compared to earth, but with an geostationary altitude (Say, at the top of a 22,236 mile tall flag-pole) you wouldn't feel any gravity. It would be like free-fall. APL (talk) 02:16, 23 December 2011 (UTC)

The OP's question is answered in Hill sphere. HTH, Robinh (talk) 07:46, 23 December 2011 (UTC)

These help, thanks. So basically, if the geostationary satellite were the same size as a football field, an astronaut could not stride upon it like we would in an airplane, even if it were between him and the earth. I know it's way to small to have any significant gravitational effect (that's not what I was really going for to begin with anyway). Mingmingla (talk) 18:06, 23 December 2011 (UTC)

Right. I'll note that APL's description of a ludicrously tall flagpole is exactly the same situation as one would experience at different positions along the cable of a space elevator. TenOfAllTrades(talk) 16:50, 24 December 2011 (UTC)

Wanted: Uranium asteroids?

Is there any asteroids or space objects like in the asteroid belt or those that do a "fly-by", that contain Uranium(oxide) in any useful isotope and amount like >1% ..? Electron9 (talk) 04:22, 23 December 2011 (UTC)

Maybe? Probably? There are all but certainly asteroids with deposits of uranium. Asteroids of > 1% uranium and of substantial size (i.e. not just a fistful of uranium ore) are, I expect, highly unlikely, as that's orders of magnitude above the expected concentration of uranium. — Lomn 14:17, 23 December 2011 (UTC)

As Lomn notes, there will be trace amounts of uranium in just about any asteroid you care to lay your hands on—the difficulty is in finding a concentrated ore. Our article on uranium ore gives a pretty thorough overview of the natural processes by which uranium is typically concentrated to form commercially-viable deposits. All of the known processes involve flowing magma, flowing water, or copreciptiation or chelation with carbon compounds in water—or more often, a combination of these processes. Unfortunately, none of these things will happen to any great extent on an asteroid; they're too cold and too small for flowing water, let alone flowing rock. You may get very small, localized deposits, but that's it.

I suppose it's conceivable that a uranium-rich asteroid could be formed by a major impact event; if you hit a pre-existing planetary deposit of uranium ore with a big asteroid or comet, then at least some of the uranium ore could be kicked off into space to become a uranium-rich asteroid. (It's believed that the moon formed through one such particularly large impact.) Still, the odds against that happening are...astronomical. TenOfAllTrades(talk) 15:45, 23 December 2011 (UTC)

Well Uranium in any form would do, even Thorium in larger amounts. As both can be used to fuel a reactor to produce electricity beyond where solar power can be utilized. I wonder if any survey has been done at all regarding this. The article on the Asteroid belt mentions some elements. The Uranium on this planet was not produced here, so there ought to be more of it in space. The processes of magma, water flow, copreciptiation and chelation with carbon compounds in water can't be needed to produce these elements. Electron9 (talk) 03:28, 24 December 2011 (UTC)

Those processes aren't needed for production, but they are a key part of concentration. Asteroid mining is undoubtedly a good SF-style source of materials (of all types, not just radioactives), in large part because the whole thing is already out of Earth's gravity well. However, until practical industrial-scale interplanetary travel is achieved, bringing the cost of space industry below that of its terrestrial counterpart, the whole thing will remain strictly within the realm of SF. — Lomn 15:48, 24 December 2011 (UTC)

"prealloy"?

I was reading Ferrosilicon and came across the term "prealloy". What does it mean, and why isn't there a Wikipedia article for it? Looks like it's something to do with a state were metals and such are physically combined, but not yet alloys at the atomic level. Especially on guitar strings, apparently. --Shirt58 (talk) 06:04, 23 December 2011 (UTC)

Prealloy is an article that exists, but it is very short. It does have a rudimentary definition. There's also a reference in the article, which you could follow. --Jayron32 03:47, 24 December 2011 (UTC)

I'm fairly sure the editor who started that article may have added the article maintenance tag "This article may contain original research" because there is currently no "This is educated guess-work, but nevertheless still guess-work" article maintenance tag.--Shirt58 (talk) 13:45, 24 December 2011 (UTC)

motion in speed of light

why it is not possible to give a movement to an object with the speed of light? — Preceding unsigned comment added by Sahir jutt (talk • contribs) 06:30, 23 December 2011 (UTC)

Because, according to the math involved, it would require infinite acceleration. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:28, 23 December 2011 (UTC)

The closer to light speed you measure something to be moving, the less increase in speed you will get per unit of energy you use to speed the object up. The way this works out is so that no matter how much energy you put in, you will never get the object to quite light speed. If you are interested, look up Special Relativity, this is the subject that covers the details of why light speed is unobtainable and why it is important. Phoenixia1177 (talk) 08:42, 23 December 2011 (UTC)

That raises a question I've sometimes wondered about: How is it that photons can travel at light speed, with seemingly very little energy input? ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:03, 23 December 2011 (UTC)

I think it's because the photon is (as we presently understand it) massless. The infinite energy to accelerate to light speed bit holds true only for objects which have mass. --Ouro (blah blah) 16:43, 23 December 2011 (UTC) sorry this got lost in edit-conflict. DMacks (talk) 21:52, 23 December 2011 (UTC)

That's because photons have zero rest mass. They are massless. Dauto (talk) 17:10, 23 December 2011 (UTC)

Sorry about that, I shouldn't have left that that off. As, clearly answered above by Dauto, things travelling at light speed have zero rest mass. The converse also holds, things with zero rest mass travel at light speed. Phoenixia1177 (talk) 17:38, 23 December 2011 (UTC)

So, infinity times zero equals the speed of light? ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:05, 24 December 2011 (UTC)

The mathematics of mechanics calculations at or near the speed of light aren't trivial. See Special_relativity#Physics_in_spacetime. No, I don't really understand it either. But it isn't as simple as the basic mechanics math you were taught in high school physics for calculating things like velocity and distance and time. --Jayron32 03:49, 24 December 2011 (UTC)

"[I]nfinity times zero" is Not a number (Indeterminate form). It is undefined. In some sense it equals every number, in some other sense it equals none. --Martynas Patasius (talk) 14:53, 24 December 2011 (UTC)

Could Solar roadways also reclaim the energy of vehicles pressing down on the pavement?

The Solar road movement is gaining momentum in various places. I now wonder whether even more use can come out of them by also capturing the energy of the weight of vehicles pressing down on said roadways.

Couldn't anyone else have thought of this idea already or am I the first one? (Please post links.)

How viable is it for solar roads to have the two ways to capture energy? Will it thusforth pay for itself faster? Thanks. --76.250.249.130 (talk) 07:39, 23 December 2011 (UTC)

Weight cannot produce energy unless some motion is involved. The energy would have to come from the engines of the vehicles travelling along the road, thus increasing fuel consumption and further polluting the planet. Sorry -- forget it! Dbfirs 07:48, 23 December 2011 (UTC)

Motion is VERY MUCH involved. The motion of the tires rolling onto each panel section is the motion needed, is it not? If not, then would a physics major please explain how? --76.250.249.130 (talk) 08:41, 23 December 2011 (UTC)

Work is done, and energy recovered, only if there is motion in the direction of the force. Weight acts vertically downwards. The motion of the car on a horizontal surface is perpendicular to the weight, so no energy can be obtained from the weight as the vehicle moves forward. Work is done against friction as the tyres roll forward, and energy could be obtained by placing miniature plates that are depressed by the tyres, but this will significantly increase "friction" and hence fuel consumption and pollution, and is a very inefficient way to produce energy. Forget the idea. It is a non-starter. Dbfirs 10:45, 23 December 2011 (UTC)

Why does concrete & asphalt need to be replaced every so often, and why are there weight limits for trucks? Isn't that because the pressure of all that traffic bearing down on the roads is wearing out the surface? Then as the weight is bore down on the roads, if that's not energy pressing down on it, then what else would it be? --75.39.138.86 (talk) 15:59, 23 December 2011 (UTC)

Moreover, if the weight pressing down on solar surfaces won't be a viable source of reclaimable energy, what about absorbing the heat from the tires? (And maybe the engines themselves, if their proximity is close enough?) --75.39.138.86 (talk) 16:05, 23 December 2011 (UTC)

(Edit Conflicts) There was mention of experiments (possibly in The Netherlands) with roadways designed to recover energy from vehicle movements in this way a couple or so years ago in New Scientist magazine, so someone has actually investigated the possibility. As I recall, the main drawback was that (just as the commenters above have said) the movements in the road's surface necessary for harvesting any appreciable energy significantly slowed the vehicles, causing them to burn more fuel for the same speed and/or mileage - effectively, the process converts some of the energy from the vehicles' stored fuel, via their engines, their wheels and the road's recovery system, to energy that then gets re-stored, very inefficiently. It would be far more efficient simply to allow the vehicles to move unimpeded as normal, and use the extra fuel not used to generate energy directly in a conventionally efficient engine. {The poster formerly known as 87.81.230.195} 90.197.66.126 (talk) 16:10, 23 December 2011 (UTC)

The weight limits for trucks are usually because of bridges, but the tyres of a heavy truck do gradually tear up the road surface, especially when braking and on corners. Recovery of heat from the tyres and engine is certainly possible, but is very inefficient. How would it be collected? Thank you to "The poster formerly known as 87.81.230.195" for explaining the problem more clearly than I did! Dbfirs 17:28, 23 December 2011 (UTC)

Kinetic sidewalks: How viable are they?

If it's possible to build a Solar sidewalk, how easily developed & constructed can such sidewalks be made to recapture the kinetic energy of anyone walking on it? How much quicker would it pay for itself if it could also capture the energy of anything pressing its weight down on it? Thanks. --76.250.249.130 (talk) 07:39, 23 December 2011 (UTC)

This idea possibly has some validity, since walking is such an inefficient method of locomotion, but such a sidewalk would be noticeably harder to walk along and very expensive to maintain. A better idea would be capture the wasted energy of those who visit gymnasiums. Dbfirs 07:52, 23 December 2011 (UTC)

Sir, aren't solar panels made today already rated for a 20, 30 or 40-year lifespan? Longer than normal concrete/asphalt now, right? --76.250.249.130 (talk) 08:43, 23 December 2011 (UTC)

They are not designed for being walked on, and they cost many times the cost of concrete. Does anyone make solar panels with a 40-year guarantee? Dbfirs 10:57, 23 December 2011 (UTC)

Is walking an inefficient method of locomotion ? Isn't it one of the most efficient other than cycling (or possibly falling) ? Sean.hoyland - talk 08:07, 23 December 2011 (UTC)

Cycling is much more efficient because the centre of mass doesn't move up and down as it does with walking. Walking on a surface that moves down as you put your weight on it would be less efficient, and some energy could be recovered, but it would not be popular, and it would be very expensive to build, with many moving parts. Dbfirs 10:57, 23 December 2011 (UTC)

Cycling is a LOT more efficient mostly because of the mechanical advantage provided by gears. --Jayron32 00:19, 24 December 2011 (UTC)

On the contrary, energy is lost in any gearing mechanism, reducing the efficiency (but, of course, making it much easier to cycle uphill). Dbfirs 10:36, 24 December 2011 (UTC)

Whey

Does whey protein consumption cause hair loss or impotency? — Preceding unsigned comment added by 119.235.51.130 (talk) 11:28, 23 December 2011 (UTC)

No. Of course, if you're substituting a whey protein shake (human breast milk is high in whey content, so there's no issue of any protein "incompatibilities") for a proper diet, everything is possible, but it's not the whey. PЄTЄRS J V ►TALK 04:02, 25 December 2011 (UTC)

Time Dilation

Do we have an article that shows the derivation of the special relativistic formulae? — Fly by Night (talk) 13:40, 23 December 2011 (UTC)

Do you mean the Lorentz factor? There are a variety of ways to derive it; one is shown in the linked-to article. If you Google "lorentz factor derivation" you can find other approaches as well. As far as derivations go it is pretty straightforward — it is just relatively simple geometry with a constant speed of light. --Mr.98 (talk) 14:07, 23 December 2011 (UTC)

It's not too hard to just follow the derivations in section I of Albert Einstein's 1905 paper, in which he first explained his theory. Here's an English translation.[5] Red Act (talk) 15:37, 23 December 2011 (UTC)

Thanks to you both. I wasn't asking how to derive the formulae; I was asking if we have an article about how to derive the formulae. I couldn't find one, and was thinking about writing one. — Fly by Night (talk) 16:19, 23 December 2011 (UTC)

which colour light travels speed and for long distance?

dear frens, i have following query: among all known colours(including white),which colour light travels for larger distance? and which colour light travels with larger speed?

-Regards — Preceding unsigned comment added by Challenging arjuna (talk • contribs) 14:37, 23 December 2011 (UTC)

All colors of light travel at the same speed, the speed of light. And in space at least, all colors of light can essentially travel for arbitrarily long distances, although for such extremely long distances that red shifting due to the metric expansion of space is significant, light that starts out as violet is the visible light that can travel the furthest while still remaining in the visible spectrum (assuming all observers involved move along with the Hubble flow). Red Act (talk) 15:26, 23 December 2011 (UTC)

Well, all colors of light travel at the same speed in a perfect vacuum. Light travels a bit slower whenever it passes through any medium (air, water, glass, or whatever). The ratio between light's speed in a vacuum and its speed in a particular medium is that medium's index of refraction. Travelling through the air, light travels about 0.03% slower than it does in a vacuum; travelling through glass, light only goes about two-thirds as fast as it does through vacuum.

Further, the refractive index of a medium isn't the same for all wavelengths (colors) of light. The change in refractive index with wavelength is known as dispersion. (Dispersion is what makes it possible for a prism to separate a beam of white light into its component colors, as each color behaves a little bit differently as it enters, passes through, and exits the glass.) Inside a chunk of ordinary glass, blue light will travel about 2% faster than red light. In general, light at shorter wavelengths will travel faster through a medium than light at longer wavelengths. TenOfAllTrades(talk) 16:34, 23 December 2011 (UTC)

All light is the same. The color is just how energetic it is. That is, how "fast" it goes. As far as we can tell, they all go the "speed of light", but if you start moving, the color changes instead of the relative speed. If light is actually massive, and we just can't tell because it moves very, very close to the "speed of light", then higher energy light (bluer) is faster and lower energy light (redder) is slower. Also, the "speed of light" is a universal constant and isn't just how fast light goes. For one thing, it's the lowest upper bound for how fast massive objects can go. As such, it still means something even if light doesn't go that fast. — DanielLC 07:57, 25 December 2011 (UTC)

LED v/s CFL?

dear frens, i have following query: i have read articles on LED and CFL in net..but still can anyone of u pls tell me diff between LED and CFL in simpler terms. Which one would be best for large developing countries like india to invest on?CFL or LED considering energy efficiency and cost factor?

-Regards, — Preceding unsigned comment added by Challenging arjuna (talk • contribs) 14:40, 23 December 2011 (UTC)

India should invest on both IMHO. Dauto (talk) 16:34, 23 December 2011 (UTC)

Our Compact fluorescent lamp and LED lamp articles each have a section comparing the technologies. They differ in how much they cost to produce, how energy-efficient they are, and how long they last in various uses. The "best" choice is something we can't answer because there is no clear winner--neither is better in all aspects but both do have substantial advantages depending on what you think is important to consider. Dauto is right though...because it's a trade-off (up-front cost vs long-term savings, for example) they are both important to consider for current applications. DMacks (talk) 18:51, 23 December 2011 (UTC)

I would say buy CFLs now, and if the price goes down enough on LEDs in the future, then buy those. Since they both work with the same fixtures, it's not a major expense to switch over later. StuRat (talk) 21:24, 23 December 2011 (UTC)

CFL's should be recycled rather than dumped. They're also as fragile as eggshells. ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:03, 24 December 2011 (UTC)

That remains unclear. I'm pretty sure many fixtures remain primarily designed for incandescents not CFLs. Either way, they often appeared to be not well suited for LED lamps. Definitely at the current time luminaires purposely designed for LEDs are likely to perform better due the heat management requirements. While there will undoutedly always be a market for replacement, it seems likely to me a purposely designed fixture will always be better overall with better heat management, as well as better handling of the output to give the effect you want (and reduce loss). And in fact on the point about most fixtures being designed for incadescents, in terms of handling the output it seems it would probably be easier to design an LED to replicate the output pattern of a incandescent then a CFL.

And on that point, if you want to use CFLs, it's questionable if you should use the incandescent replacement ones with integrated ballast. Quad pin ones where the electric ballast is in fixture seem a better bet to me. And non compact fluorescents are far more common including in households in parts of Asia then in much of Europe, the US and Australia/NZ anyway AFAIK. If you aren't talking about a desk lamp or something similar, I'm not convinced there's any real reason to go CFL or whether a normal non compact fluorescent lamps.

Perhaps I will one day eat my words, but of the two I think it's clear LEDs have a far brighter future (pun semi intentional) even if they still have a way to go before clearly overtaking a CFL. (Yes people hype LEDs too much some times but I think that's more about 'when' and 'how soon' rather then 'if'.) It appears I'm not the only one who thinks this because our article notes "Philips Lighting has ceased research on compact fluorescents, and is devoting the bulk of its research and development budget, 5 percent of the company's global lighting revenue, to solid-state lighting". Of course none of this is to suggest there aren't still plenty of problems LEDs have to face.

Nil Einne (talk) 13:04, 24 December 2011 (UTC)

It's pretty clear that CFLs' time has peaked. I expect LED bulbs will last long enough that people will take them with them when they move. They can also be disposed of normally versus CFLs. The main challenge right now (aside from costs, which are already dropping as volume ramps up) is that LED maximum light output is not matching CFLs (which are readily available in up to 200W incandescent luminescence equivalents). PЄTЄRS J V ►TALK 03:55, 25 December 2011 (UTC)

Why does a tubelight does not start as soon as it is switched on?

dear frens, this is my query:

1.Why does a tubelight does not start as soon as it is switched on?but an electric bulb/CFL will switch on as soon as it is switched on... — Preceding unsigned comment added by Challenging arjuna (talk • contribs) 14:47, 23 December 2011 (UTC)

Flourescent_tube#Starting pretty much explains that. FWIW CFLs in fact do have a delay, but this has been improved over the years; see Compact_fluorescent_lamp#Starting_time. It also depends on the design; some of my CFLs have a noticeable delay in starting (possibly around 1 sec) followed by a further period of up to a few minutes until they reach full brightness, others come on virtually immediately, are generally brighter when they come on, and while still having a delay before reaching full brightness this is quicker than the first design mentioned. Regards incandescent light bulbs, since these rely on the basic principle of simply heating a metal filament until it glows white hot, this can be achieved in a time imperceptible to our senses. --jjron (talk) 15:39, 23 December 2011 (UTC)

I have a CFL that does something a little different, it starts out dim, but instead of gradually getting brighter it snaps to full brightness a second later. I wonder how they got that effect. StuRat (talk) 21:22, 23 December 2011 (UTC)

While incandescents (generally) illuminate faster than fluorescents, it's not quite correct to say that the time that they take to turn on is completely imperceptible. If you compare an incandescent bulb and an LED lamp side by side, you will be able to see the difference quite clearly. The LED will 'snap' on and off, while the incandescent 'fades' in and out. This usually isn't an important difference, but it has a key application in automotive safety. Studies have found that replacing incandescent brake lamps with LED brake lamps improves driver response times by about 200 milliseconds: [6]. (At highway speeds, 200 ms is about 6 meters (20 feet) of travel.) TenOfAllTrades(talk) 16:17, 23 December 2011 (UTC)

I don't think any of this answers the OP's question. The tubelight has a chock to store the energy with which to strike the arc. The circuit’s electronics can only wait until the bimetallic switch has warmed up enough to complete the circuit to dump that energy between the tube's cathodes. That is where the delay occurs.--Aspro (talk) 21:57, 23 December 2011 (UTC)

And here is the circuit. The delay is due to component 'D'. Wikipedia had the answer all the time; should one look for it.--Aspro (talk) 22:11, 23 December 2011 (UTC)

Sugar = non-aqueous

I remember hearing in Chemistry class that sugar is a homogeneous mixture (I think), unlike salt which is aqueous. Does that mean that if you let a glass of water with sugar in it sit for long enough, without letting the water dissolve, that the sugar will not float to the bottom due to gravity? I'm assuming that the interactions between atoms of the molecules is enough to keep the sugar in such a state. Magog the Ogre (talk) 16:32, 23 December 2011 (UTC)

I think you are remembering that sugar (sucrose) is a covalent compound that stays as whole molecules when it dissolves in water whereas table salt (sodium chloride) is an ionic compound that separates into individual atoms when it dissolves in water. But either way, you have an actual homogeneous solution even down to the molecular level not simply macroscopic particles spread among each other (like sand in water). There are reasonably strong attractions between the solvent (water) molecules and solute (sugar molecules or salt ions) that actually keep them mixed and prevent settling-out or other spontaneous separations. Technically, it is more stable for them to be dispersed among each other than to coalesce into clusters apart from each other. DMacks (talk) 16:43, 23 December 2011 (UTC)

physics

well there was a question in which there was a very small angle, and in the question it was noted that the angle x is so small that sinx=tanx=x and while I was solving the problem, I chose the approximations in a way that the problem could be solved, for example, when there was

integral(sinx-tanx)d(tanx), what I did was: integral((1-1/cosx)sinx)d(tanx)=integral(1-1/cosx)sinx dx=-integral(1-1/cosx)dcosx=ln(cosx)-cosx

is it right in principle to do so?--Irrational number (talk) 19:50, 23 December 2011 (UTC)

You should probably try WP:RD/MA. Magog the Ogre (talk) 23:55, 23 December 2011 (UTC)

Hospital admission procedures

First-time poster.

At a gated Internet community, we're writing a collaborative science fiction story. It is a tale of inner-body travel, set in the year 2028. A 16-year-old boy named Steve has just been driven via ambulance to the hospital after passing out at his job site, having a prion-caused disease that kills everyone who has it.

What we'd like to know is: what are the procedures that doctors and nurses do with new patients admitted to a hospital? Among other things, we'd like to know what the standard list of questions for in-patients is. (Things like . . . "What's your full name?", "Are you allergic to any medications?", "What diseases and disorders do you have a history of in your family?")

If we could get some help from someone here who works in the medical professional, our online community would be eternally grateful. Enzingiyi (talk) 20:43, 23 December 2011 (UTC)

Starts with asking a Medical history. --BozMo talk 21:15, 23 December 2011 (UTC)

In the US, at least, they will want to know about your insurance, to determine if they should release you immediately or perform a million dollar surgery. :-) StuRat (talk) 21:17, 23 December 2011 (UTC)

With two ER admissions in the past year, I will try to recall. If you are conscious, the admissions nurse will ask why you are there, have you ever had a similar condition before, are you in pain? Do you have a family (or a regular) doctor? Who is it? Can we have permission to obtain your medical records? Where is the pain? How intense is it? When was the last time you ate? What did you have? Are you on any prescription medications? Have you taken any non-prescription drugs in the past week? How often do you consume alcohol? How often do you use any other drugs, legal or illegal? Are you allergic to any foods or medications? (This is just the beginning, and the sequence may be different.) A nurse will routinely take blood pressure, temperature, basic height and weight info. You will probably be asked to provide a urine sample. Insurance information will also be taken, but in the U.S., emergency facilities are required to treat emergency medical situations regardless. This is all before you see a doctor. The doctor may repeat some of these questions, and may ask for a routine blood sample to be drawn. Results of this preliminary exam will determine the direction it proceeds further. — Michael J 23:06, 23 December 2011 (UTC)

Thanks for all your help, guys! Enzingiyi (talk) 20:12, 24 December 2011 (UTC)

Quenching and tempering

My understanding, which I've checked on the Wikipedia page is that, quenching steel increases its Vicker's Hardness, tempering should slightly decrease the Vicker's Hardness whilst increasing its ductility. However in a set of results I have for an experiment testing this, the Vickers Hardness of the quenched and tempered steel is slightly higher than that of the quenched. Is this likely an error in the experiment or is there a scientific explanation for this? Clover345 (talk) 23:06, 23 December 2011 (UTC)

Likely the manner of quenching/tempering: degree and manner of conversion of austenite to martensite and retained austenite, influence of the thickness of the material, and so on. You need to review your process in detail to work through its expected effect on the crystalline structure. How soon you measured hardness might also influence; on re-tempering, you need to allow 24-48 hours to pass before re-measuring hardness, but I don't know if that also applied to initial tempering. (Just curious, did you get the same results measuring hardness a couple of days later?) PЄTЄRS J V ►TALK 03:47, 25 December 2011 (UTC)

Aspirin and gastrointestinal bleeding

Why is the stomach damaged by Aspirin? Isn't it acid-resistant? Aspirin#Gastrointestinal describes the phenomenon, but does not explain the why. 88.8.69.150 (talk) 23:46, 23 December 2011 (UTC)

It's more about the the "salicylic___" aspect rather than the fact that it's an acid. That is, there's something else about the structure that matters. Aspirin is actually a fairly weak acid too, so it's not even noticeably "acidic" in already highly acidic stomach (that is, as you note, it doesn't seem reasonable for it to be causing acid burns or similar effects). As a result, it is likely to be mostly in its neutral form, and therefore can interact more easily with certain types of tissues and membranes. I don't know any of the specifics for it (which types of cells are affected, the actual mechanism, etc.) though. DMacks (talk) 08:00, 24 December 2011 (UTC)

If I recall correctly (which I may not), the reason aspirin can sometimes cause damage to the gastric lining is for the same reason that aspirin works — namely, that it inhibits the action of COX, and thereby interferes with the synthesis of prostaglandins. That's the way it controls inflammation and pain, but it also interferes with the way the gastric mucosa protects you from your own stomach acid.

By the way, I don't think salicylic acid in fact does act that way, particularly, though I'm not sure of that either. The aspirin article claims that aspirin works by irreversibly acetylating COX, which is something salicylic acid can't do (it has no acetyl group). --Trovatore (talk) 10:34, 24 December 2011 (UTC)

Well, it used to claim that. It seems to have been changed. I'm not sure what the exact situation is and would be interested in clarification from anyone who has better information. --Trovatore (talk) 07:13, 25 December 2011 (UTC)

December 24

what travel is?

Base on our current technology, what is more likely to happen first.. Travelling thru time or travelling thru other galaxy in short period of time, (like going for a vacation in other galaxy). MahAdik _usap 01:15, 24 December 2011 (UTC)

That's easy. Under our current technology, traveling to another star (never mind galaxy) and living to tell about it, is impossible. Travelling through time is not only possible, but we're doing it right now. :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:17, 24 December 2011 (UTC)

(edit conflict) We already travel through time, but it is a one-way trip. Interstellar travel is a future possibility, though if we were to do it in a short amount of time that would, of itself, be its own form of time travel. An interesting treatment of the matter, if you are interested, is the song "'39" from the band Queen. It was written by the guitarist Brian May, who is also a trained astrophysicist and has a good grasp on the time-related issues of interstellar travel. --Jayron32 01:21, 24 December 2011 (UTC)

From what I read it's possible for subatomic particles at present to travel back in time. But no further than the start of the machine. I guess traveling through loopholes in space is more likely. Electron9 (talk) 06:20, 24 December 2011 (UTC)

I don't believe that is exactly correct. My understanding is that mathematical physics does not disallow negative time (backwards time travel), for example Closed timelike curves are hypothetically possible. Also, it is possible, in my understanding, to work the mathematics so that a particle described as having some "negative" properties to be mathematically equivalent to moving backwards in time. That doesn't mean that the particles actually travel backwards in time, just that the mathematics doesn't disallow it. The Chronology protection conjecture also has some interesting things to say on the matter. --Jayron32 06:31, 24 December 2011 (UTC)

Another area would be to be able to probe the past to see what really happened etc. Ie move information, not people. Electron9 (talk) 09:13, 24 December 2011 (UTC)

Moving information backwards in time (or, rather, arbitrarily moving information at a past point in time forward in time, to the present) is as prohibited by current science as moving people is. I wouldn't wait up for it. Also, it seems like kind of a bad idea. --Mr.98 (talk) 14:00, 24 December 2011 (UTC)

Probing the past wouldn't involve sending information backwards in time, it's about getting information from the past. We do that whenever we look at things - we see them as they were when the light left them. If you can set up or find a suitable mirror, you can see whatever you like at any point in the past (as long as it is long enough ago for the light to have reached you in a straight line). --Tango (talk) 14:26, 24 December 2011 (UTC)

You could hypothetically set up a mirror today which would reflect information about today into the future, so that future people can investigate what happened today (whether this is technologically possible is neither here nor there. It is merely not disallowed by the physics). What you cannot do is outrace the light from the past and install a mirror to catch that light and reflect it to today. That train has already left the station, as it were. --Jayron32 15:31, 24 December 2011 (UTC)

The theory would be to either somehow reconstruct or retrieve photons from the past. So maybe you could actually watch famous events or find out details otherwise impossible to find out. The other approch is to exploit some quantum or subatomic particle interaction such that past events can be sufficiently reconstructed.Electron9 (talk) 17:24, 24 December 2011 (UTC)

That's where finding the mirror comes in - a black hole in just the right position could cause the light to do half an orbit around it and come back the way it came. It's unlikely that you could find one just where you wanted it, but it's physically possible. --Tango (talk) 20:04, 24 December 2011 (UTC)

Assuming the OP means travelling in time at an arbitrary and possibly negative rate, going to another galaxy is "more" likely, with "more" in scare quotes because both are completely impossible with any technology we have now or will have in the foreseeable future. The difference is that travelling to another galaxy in a (subjectively) short time is at least theoretically possible due to time dilation, whereas our current understanding of the universe essentially prohibits backwards time travel entirely. Forward time travel at a rate noticeably greater than one second per second doesn't require any technology that is very far beyond what we have now, and is even a prerequisite to getting anywhere out of the solar system in a reasonable subjective time-frame. Of course, going for a vacation in another galaxy sort-of-implies returning and expecting to see Earth more or less as you left it, which requires backwards time travel anyway. We do have some ideas on how backwards time travel could be possible, but they tend to involve negative mass (and lots of it, too), which probably doesn't exist in any usable form. The Casimir effect might work (see the section "Wormholes" in that article), but even then, the effect is so incredibly tiny compared to the vast negative energies required for wormholes or Alcubierre drives capable of transporting a human (plus life support systems, baggage, etcetera) that I'd say hyperrelativistic spacecraft are still more feasible. --Link ^(t•c•m) 10:24, 24 December 2011 (UTC)

Travelling backwards in time and travelling faster than the speed of light (which I expect are the two things you are really asking about) are essentially the same thing, according to general relativity (just from a different point of view). If we can find a way to do one, it will probably allow us to do the other as well (not definitely, because if we do find a way to do one of them, it could be because general relativity is wrong so they aren't necessarily equivalent after all), so I would say they are equally likely (which is to say, both extremely unlikely). --Tango (talk) 14:22, 24 December 2011 (UTC)

The theory regarding speed of light seems to been broken by neutrinos this year. Other discoveries may show up. Is negative mass different from anti-matter? Electron9 (talk) 17:24, 24 December 2011 (UTC)

Chances are there is something else going on with those neutrinos rather than them actually violating a fundamental principle of special relativity. Anti-matter has positive mass, but opposite electric charge. Matter with negative mass is often called exotic matter and there is no evidence that it exists. --Tango (talk) 20:00, 24 December 2011 (UTC)

They're the same thing. If you can move faster than light, you can go one way, change your point of reference, go the other way, and end up where you started before you left. If you can go back in time, you can go to another galaxy the slow way, then go back in time to "when" you left (scare quotes due to the relativity of simultaneity). Admittedly, that second one isn't very useful if you don't have cryonics or some other way to make taking a trip like that not seem to take forever. I suppose you could take the trip really, really fast, so time dilation makes it seem like it doesn't take very long. — DanielLC 07:50, 25 December 2011 (UTC)

Differnce

Whats the diff betweemn virginal hypertrophy and macromastia. And where can i get pics?--213.98.69.99 (talk) 14:20, 24 December 2011 (UTC)

Have you read Hypertrophy of breast? If not, start by reading that and then come back if you have any further questions. --Tango (talk) 14:23, 24 December 2011 (UTC)

Is it true that electricity was originally used almost exclusively for just lighting?

Topic says it all. ScienceApe (talk) 14:47, 24 December 2011 (UTC)

I don't know about that. Electricity was vital to the Electrical telegraph, and that was in widespread use several decades before Edison's light bulb was. --Jayron32 15:26, 24 December 2011 (UTC)

Domestically, it may be true, though. I think when houses were first being connected up to electricity supplies, it was primarily for lighting. Edison played a key role in setting up the first mains electricity supply, so I wouldn't be surprised if it went along with his light bulb. The relevant article seems to be History_of_electrical_engineering#19th_century_developments, but it's a little light on details (no pun intended). --Tango (talk) 15:38, 24 December 2011 (UTC)

Ah, I can do better than that. Electricity_distribution#History says: "Low DC voltages were used (on the order of 100 volts) since that was a practical voltage for incandescent lamps, which were the primary electrical load." It doesn't say it was exclusively used for lighting, but it was primarily used for lighting (in the domestic setting - obviously there were telegraphs and other specialist uses as Jayron mentions). --Tango (talk) 15:44, 24 December 2011 (UTC)

Electric lighting was the killer app for electricity in the early days of domestic use. Edison gets a lot of credit for inventing the light bulb (which is only partially true), but he ought to get the most credit for creating the first electricity infrastructure. --Mr.98 (talk) 01:15, 25 December 2011 (UTC)

The first public electric utility was in New York (Edison's), the first use of electricity being for light (residential and commercial) and power (commercial enterprises using electric motors). Used to walk past the building all the time when I worked in downtown NYC. PЄTЄRS J V ►TALK 03:18, 25 December 2011 (UTC)

evolution

if any one gives me a Wikipedia article on this, it's enough. I saw a youtube video in which the uploader claims that there is no known mechanism under which genes "add", and goes on to compare the number of genes in humans and bacteria.Now even if he/she is right, it doesn't disprove evolution, just because of something we don't know YET, but... is it true?--Irrational number (talk) 20:30, 24 December 2011 (UTC)

How about gene duplication? --69.113.197.155 (talk) 20:36, 24 December 2011 (UTC)

is it the only one?--Irrational number (talk) 20:52, 24 December 2011 (UTC)

Genome#Genome_evolution is a good starting point, also be sure to check out horizontal gene transfer. --69.113.197.155 (talk) 22:34, 24 December 2011 (UTC)

December 25

Help identifying plant pest

Please see this imgur album. Something is creating these on my houseplants, and I'd like to know what so I can figure out how to kill/discourage it. Thank you! The Masked Booby (talk) 07:32, 25 December 2011 (UTC)

Forgot to add I live in China. The Masked Booby (talk) 10:49, 25 December 2011 (UTC)

Looks like a mealy bug to me, or a scale insect. --TammyMoet (talk) 10:56, 25 December 2011 (UTC)

Neurofeedback in time management

I've read that EEGs can measure attention fairly accurately. Has the effectiveness of using it in time-management software, to determine when a user should switch tasks or whether to repeat a reminder, been studied? (I'd expect it to be particularly helpful for users with autism spectrum disorders or ADHD who hyperfocus.) NeonMerlin 08:02, 25 December 2011 (UTC)

Even if it works, how do you suppose that we use it? I can hardly carry an EEG machine with me, or have I missed the question entirely? Plasmic Physics (talk) 13:06, 25 December 2011 (UTC)

In principle it ought to be possible, because the EEG pattern during a state of focused attention is quite different from the EEG pattern of somebody whose attention is wandering. Several companies that provide neurofeedback products claim that they are useful in time management, but I don't have much faith in the reliability of those claims. There is, however, some proper research showing that neurofeedback is sometimes helpful to people who have ADHD. Looie496 (talk) 18:14, 25 December 2011 (UTC)

Whereas a Defibrillator was invented to restart hearts, what needs to be invented to restart brains?

Also, what must be developed and overcome in order for a brain-restarter to be made that will bring back the activity of life to the brain? --75.39.137.175 (talk) 08:38, 25 December 2011 (UTC)

Magic needs to be invented. Hearts are nothing like brains, your logic does not follow. A brain cannot be restarted by electricuting it. Plasmic Physics (talk) 12:57, 25 December 2011 (UTC)

(Atleast not in the same way.) To restart a brain you'd have to create a very specific neorological stimulation pattern, much like taking a second photograph that looks exactly the same as the first, accurate down to the pixel level. Impossible to do with current technology, or technology in the foreseable future. Plasmic Physics (talk) 13:02, 25 December 2011 (UTC)

A defibrillator does not restart the heart, it just forces it into synchrony -- see fibrillation. A heart that is completely stopped cannot be restarted. The brain equivalent of fibrillation is an epileptic seizure, but epileptic seizures stop of their own accord when the metabolic energy of the brain runs down. Looie496 (talk) 18:02, 25 December 2011 (UTC)

Is there a brain EKG?

Whereas EKGs are for heart activity, what's a device that gives us readings of brain activity? --75.39.137.175 (talk) 08:38, 25 December 2011 (UTC)

EEG is what you're describing. Also, see fMRI or a PET scan with 18F-FDG for different ways of detecting brain activity. Fgf10 (talk) 09:46, 25 December 2011 (UTC) _{Edit:forgot to log in.}

Animals don't like the taste of humans?

Why is that predators usually don't hunt humans for food? In the rare cases they do attack humans, they do it for other purposes than hunting, for example they feel threatened, and even if they kill a human, they usually don't consume the corpse. Is there something special in our meat that makes it unhealthy or untasty for them, or is it more that the animals learned to fear and avoid humans (because of hunting, making loud noises, etc.) ? --79.116.95.237 (talk) 17:40, 25 December 2011 (UTC)

(Adult) Humans are quite big. There aren't many predators that will hunt such large animals. Big cats will, but that's all I can think of. Those few that do would rather hunt things that don't fight back so effectively (we are particularly good at working together to defeat predators, which is a key different between us and, say, antelope). Animals learn from experience, the same way we do - when they hunt antelope they get a nice meal, when they hunt humans they get shot (or speared, or hit on the head with a rock, or whatever). There is probably an evolutionary aspect as well - those individuals that tried to hunt humans didn't do very well so weren't able to pass on those genes, while those that gave humans a wide berth did pass on their genes. (Children are another matter entirely - there are plenty of animals that will take a human child for food given a chance.) --Tango (talk) 18:01, 25 December 2011 (UTC)

Saltwater crocodiles will attack humans to prey on them. See Crocodile attack. So will Great white sharks, if given the chance. Most other animals will only attack a human in perceived self-defense, such as if a snake gets stepped on or spooked. (Actually, I've heard that a lot of snake bites happen when a human idiot tries to kill the snake. If you see a poisonous snake, you leave it alone, and it'll likely leave you alone). 58.111.186.225 (talk) 18:18, 25 December 2011 (UTC)

Pneumoencephalography in The Exorcist

The Regan MacNeil character in The Exorcist was shown to be undergoing pneumoencephalography. But the first X-ray computed tomography was done on 1 October 1971 and announced in 1972. On the other hand, Exorcist was released in 1973. If so, why MacNeil was undergone pneumoencephalography, not CT? --Xogogog (talk) 18:11, 25 December 2011 (UTC)

It typically takes years between the first time a technology comes onto the market and the time when it is widely available at an affordable price. Also, a movie typically takes a couple of years to make, and the book the movie was based on was published several years before the movie came out (if that matters). Looie496 (talk) 18:18, 25 December 2011 (UTC)