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April 21

Do all flowers need sunlight to blossom?

Having located the linked article my wife and I have had a heated debate concerning flowers. We would like the following question answered.

Do all flowers require sunlight in order to bloom? Clearly not all flowers need sunlight to develop, and not all plants need sunlight in order to survive. Our question relates specifically to the opening and blooming of flowers.

https://news.mongabay.com/2019/08/new-orchid-species-from-japan-lives-on-dark-forest-floor-never-blooms/amp/

Thank you — Preceding unsigned comment added by 2A00:23C6:6888:C600:28F4:D64D:6F71:62B8 (talk) 20:57, 21 April 2022 (UTC)

There are a lot of plants that bloom at night (see Category:Night-blooming plants) I don't know what triggers them to bloom ("when it's dark" vs "when it becomes no-longer-light"). So I'm not sure if that does or doesn't qualify for your interest. DMacks (talk) 21:50, 21 April 2022 (UTC)

BTW, all plants need some sunlight, even if not directly - see photosynthesis. Alansplodge (talk) 22:43, 21 April 2022 (UTC)

Tell it to Gastrodia kuroshimensis. (That one doesn't bloom, which is the key to the question.) --jpgordon^{𝄢𝄆𝄐𝄇} 23:04, 21 April 2022 (UTC)

This being the Science Desk and all, I think some precision is required here. Is the question asking about direct sunshine on the flowers being required for them to bloom, or just daylight? If it's the former, the answer is obviously no. Many flowering plants in deep mountain valleys never experience direct sunlight. HiLo48 (talk) 00:07, 22 April 2022 (UTC)

OP here, different computer. Without being in a cave it would be well nigh impossible to have no sunlight. The question relates to the plant receiving direct sunlight in order for the flower to bloom. Deep valleys may have flowers but they are not dark to the point of near 0 sunlight such as experienced in deep jungle floors where the flower in question grows. Thanks — Preceding unsigned comment added by 62.252.54.42 (talk) 11:04, 22 April 2022 (UTC)

Flowering room plants often do not need (and do not receive) direct sunlight. For a few examples, see here.  --Lambiam 14:21, 22 April 2022 (UTC)

OP again. Thank you, and if the flowers do not receive any sunlight such as those that exist in caves...those never bloom because they never receive sunlight? Is that accurate without deviation and exception? Thanks — Preceding unsigned comment added by 62.252.54.42 (talk) 15:24, 22 April 2022 (UTC)

There are parasitic plants that don't do their own photosynthesis, and only emerge above ground or out of the trunk of the host plant to flower and set seed. The fact that the sun shines on them at that point is probably of only indirect interest to them. Abductive (reasoning) 07:37, 23 April 2022 (UTC)

It is disappointing that the original questioner seems to have a better grasp of the issue than most of those who have responded! One study has shown that in the parasitic plant Dodder the cue to initiate flowering comes from the FT protein generated by the host and used by the host plant to initiate its own flowering. The trigger for flowering in the host plant is in most cases photoperiod, so still you need to have light in the system, although not directly illuminating the Dodder plant itself. The same article points out that "very little is known about how flowering of parasitic plants is regulated". Jmchutchinson (talk) 09:16, 23 April 2022 (UTC)

That's what I alluded to by indirect interest. Even holoparasites have to engage with the pollinators and seed dispersers, and know what season it is. An example is beechdrops (interesting that both it and dodders have an always-plural name.) Dodders is an aboveground plant and only hemiparasitic. Abductive (reasoning) 16:19, 23 April 2022 (UTC)

Dodder, singular. Bazza (talk) 09:05, 24 April 2022 (UTC)

In any case, no evidence has been presented that the light plants may need for flowers to open and bloom has to be, specifically, sunlight. Here Corydalis lutea is reported to be a blooming perennial that thrives even in dense shade.  --Lambiam 10:01, 23 April 2022 (UTC)

April 23

Physics

How I can provide that after collision and before collision of the car when it was in the road and it have a passenger,,?? — Preceding unsigned comment added by 41.222.180.178 (talk) 10:23, 23 April 2022 (UTC)

Start at traffic collision. 2A00:23A8:4306:5D01:B995:7B23:A571:2AA9 (talk) 11:16, 23 April 2022 (UTC)

The question is not fully clear. Do you want to understand the physics aspects of a car collision (as in inelastic collision)?  --Lambiam 16:21, 23 April 2022 (UTC)

Computed tomography scan and slices

I would kindly ask for information, I know that in spiral CTs the data of "slice thickness" and the distance between two consecutive slices "Spacing Between Slices" are important. However, I would like to understand if there is a gap in the CT that I performed between two slices. I mean if there is a "dark spot" not represented between two consecutive slices. I have found the following data of two consecutive slices of a ct, and I would like to ask if it was possible to calculate a possible dark spot, that is, if there is a gap not represented by images between two consecutive slices.

DATA: Spiral pitch factor. value: 0.65

slice thickness. value: 1.0

Gantry tilt: +8.5 — Preceding unsigned comment added by 37.161.25.209 (talk) 08:18, 24 April 2022 (UTC)

FIRST SLICE:

image position patient. value: -130.2261\-165.1111\1790.323

image orientation patient. value: 1.00000\0.00000\0.00000\0.00000\0.98902\0.14781

SECOND SLICE:

image position patient. value: -130.2261\-165.1111\1791.124

image orientation patient. value: 1.00000\0.00000\0.00000\0.00000\0.98902\0.14781

In practice the only value that changes is the third component of image position patient Δ=0.800 about.

I'm asking to myself if slices all overlap, that is, if there are not dead acquisition spaces or if there are, according to these data. It is absolutely not a medical question, I'm just a curious engineer about the data of the exam I took.

Thanks :) --37.160.236.73 (talk) 16:33, 23 April 2022 (UTC)

• I'm not sure, but I think the beam should be minimally overlapped during the scan (to reduce patient exposure to X-rays), then the computer processes the slices into a dataset that can be rotated into whatever 3D view the technician or physician desires. Maybe one can set the settings such that slices don't overlap and leave gaps. Abductive (reasoning) 20:01, 23 April 2022 (UTC)
• My understanding is that a pitch factor < 1 means that the distance travelled by the scanned body during one rotation by the scanned body is less than the beam width, so there is no gap. In fact, there is some overlap, which helps in stitching the slices together to a continuous sinogram, also when the patient is not absolutely still. What is as relevant from a medical perspective as the absence of significant gaps, is the resolution. If I understand the basic mathematical principles of CT correctly, only detail that is significantly wider than the beam width will be visible in the resulting image, which is also what one would naively expect.  --Lambiam 20:23, 23 April 2022 (UTC)
• Just to confirm, pitch < 1.0 means overlap.[1] DMacks (talk) 20:29, 23 April 2022 (UTC)

Thanks for answers:D! It was also my idea. Buy i read (about tilt gantry and and normal to the slice):

1- http://xrayphysics.com/ctsim.html

2- https://groups.google.com/g/comp.protocols.dicom/c/Qw2nWtElu2c

3- https://groups.google.com/g/comp.protocols.dicom/c/lEp7NmiHIT0 that instilled doubts to me. In 5° message looks like that to calculate any spacing between two slices you have to project the reference system of patient onto the machine reference system (directory cosines). --37.163.149.54 (talk) 21:52, 23 April 2022 (UTC)

Fuel source for electricity production in the US

The war in Ukraine has raised concerns regarding Europe's dependence on Russian gas/oil. But here in the US, where we gobble power.... The New Yorker states "Electrifying your home one machine at a time is today’s Victory Garden", and referred to The Hill, which recommends "Electrifying the machines we use to heat our air and water, cook our food, dry our clothes, and take our kids to school..." So, how is the electricity produced? In the US, hydroelectric is not universally available?? Same for nuclear, wind power, solar? That leaves coal, natural gas, etc. I live in a rural area, and have used "propane" (stored in a 500 gal tank) for heat, hot water & cooking, for the past 36 yrs.

My question: Is it more effective to use fossil fuels (at a power plant) to produce electricity for the end user, versus just using natural gas or "Propane"/LPG as the end user? Thanks, Tribe of Tiger ^{Let's Purrfect!} 21:41, 23 April 2022 (UTC)

The overall efficiency of "heat at the home" from various fuel-sources and routes of transmission is a popular topic. A furnace (central heating), per our article, "can be up to 98% efficient...with a typical gas furnace being about 80% efficient." That's about the most direct "burn fuel-->heat air" route. A combined cycle power plant is up to 64% for electrical generation, and then there would be further losses when that electricity is converted to heat at the home. However, even the poorest heat pump has a coefficient of performance higher than two, so when that device is used for heating, it more than makes up for the lower efficiency of the electrical generation. This is all just back-of-the-envelope...I'm sure it's been analyzed in more detail in many published references. DMacks (talk) 23:05, 23 April 2022 (UTC)

DMacks Thanks, this is helpful.Tribe of Tiger ^{Let's Purrfect!} 20:54, 24 April 2022 (UTC)

The question does not take into account the likelihood of commercial electricity generation itself becoming less and less dependent on fossil fuels in the future.

In my own country, the UK, non-fossil fuel sources (other than Nuclear power) were a negligible component of National Grid electicity supply well into my adult lifetime; as I type right right now (in the middle of the night), fossil fuels are supplying only 16.62% of the total demand, with the rest coming from Nuclear and Wind power, renewable Biomass (using purpose-grown trees and sawmill waste), plus 0.62% of Hydroelectricity. During the day Solar power makes significant contributions (averaging around 20% at noon over the past week), and stored Hydroelectic power is deployed around dawn and dusk to smooth out transitions. (See this handy site.) The trajectory is to continue reducing routine fossil-fuel use to near-zero over the coming decades.

Assuming the USA chooses to follow the same trajectory, supplied electricity there should also become increasingly non-fossil derived, so domestic electrical appliances will become increasingly less dependent on fossil fuel without the homeowner even having to do anything further to bring this about. Moreover, as the technology improves and economies of scale ramp up, increasingly efficient home installations of solar power panels and heat exchangers (as technology advances) can also be deployed where possible to reduce dependence on external supply and even yield income by selling power to the grid.

Note that "efficiency" of supply won't matter a damn if the place one lives becomes uninhabitable due to the effects of Global warming largely caused by fossil-fuel use. I personally expect this to happen in the South Western states of the USA around 2050 unless drastic measures are implemented, but I'm not an expert. {The poster formerly known as 87.81.230.195} 90.197.101.71 (talk) 02:13, 24 April 2022 (UTC)

You might want to check the EIA's prediction of fuel source for electricity 2022-2050. Bit of a drop in coal, more gas. https://www.eia.gov/outlooks/aeo/pdf/AEO2022_ChartLibrary_Electricity.pdf p5 Greglocock (talk) 07:38, 24 April 2022 (UTC)

Our article say that the US uses about 40% natural gas, 20% coal, 20% nuclear and 20% renewables for its production of electricity, so that's about 60% fossil fuels and the coal is worse than the propane you burn at home. The efficiency of fossil fuel power stations is around 50%. The most modern units reach around 60%, some claim a bit more as they say they found some use for their waste heat, but the oldest units still in use are around 40%. When you want high temperature heat (like in cooking), this electricity can be turned into heat only by resistors (induction cooking also uses a resistor, the cooking pot itself), so the efficiency is 50%. A gas stove has limited efficiency too, assuming the burners aren't too large around 60% or so, so for cooking, electrifying right now may not be much of an improvement, but gets better as the proportion of fossil fuels in electricity generation falls.

For low temperature heat, you can use heat pumps. A properly functioning heat pump has a coefficient of performance more than high enough to compensate for the losses in a fossil fuel power station. Unfortunately, heat pumps don't always function properly. In temperatures close to freezing and moist air (which, depending on your climate, may be when you need most of your heating), many types (in particular the more affordable ones) can get clogged with ice, turning them into resistive heaters, which is worse than heating your home with gas directly.

So, yes, electrifying your home helps, but it's not magic. Try to cut back on energy use, get solar panels if you haven't already and tune you power consumption to match generation of the solar panels during the day. And I've got no kids, but when I was one myself, I went to school by bike. Fully muscle powered, it doesn't get cleaner than that. PiusImpavidus (talk) 09:29, 24 April 2022 (UTC)

In California where I live, as of 2020, electricity is generated 48% by natural gas, 15% by solar, 11% by hydroelectric, 9% by nuclear, 7% by wind, 6% by geothermal and 3% by biomass. Coal, oil and waste heat are negligible factors here. See this government report for details. Cullen328 (talk) 02:44, 27 April 2022 (UTC)

April 24

handheld scale

I was at an outdoor Chinese market and the lady there weighed vegetables on a handheld scale that looked pretty cool, primitive and yet totally functional. I didn't manage to look at it closely since she didn't seem to like it when I tried. I am wondering what it worked. I think it may have been a steelyard balance but according to the article, those work by having the weighing pan at one end, the pivot in a fixed location some distance from the end, and a sliding weight that you move on the arm to make the arm horizontal.

I am wondering if there is a known variant of this, where the weighing pan is fixed at one end of the arm, the counterweight is fixed at the other end, and you move the pivot until the arm is horizontal. The pivot would be a knife-like edge and the arm would have a bunch of marked notches for different weights. So you'd put the knife edge under whichever slot brought the whole thing into balance.

If that's not a common design, is there a reason it wouldn't work? I'm thinking of making something like it as a very portable weighing scale. Materials would be a wooden chopstick as arm, pocket knife blade for pivot, and water bottle or similar for counterweight. Thanks. 2601:648:8202:350:0:0:0:4671 (talk) 07:50, 24 April 2022 (UTC)

Well it would work, but (if I understand correctly) to adjust it you would need lift much of the mechanism plus the load, rather than simply slide a small mass along the bar, so it would be a bit fiddly. And it would only be as accurate as the distance between the notches.--Shantavira|^{feed me} 08:21, 24 April 2022 (UTC)

A simpler design is the traditional apothecary’s balance, and our weighing scale article also has some details. Alansplodge (talk) 09:53, 24 April 2022 (UTC)

Thanks both. The apothecary balance is a double pan balance that needs a set of weights, so it doesn't seem practical here. I'm trying to have something very lightweight and simple. Lifting the balance with the load isn't likely to be a problem since it would only be for weighing light stuff. I gave the example of a water bottle (500g of 1kg) as counterweight but in practice the loads and counterweights would be a lot lighter, like a few ounces. 2601:648:8202:350:0:0:0:4671 (talk) 10:55, 24 April 2022 (UTC)

Chinese "daching" scales for traders were first mentioned in western literature in the 17th century as "dotchin" scales. They are a type of steelyard. On one side of a horizontal rod hangs the pan and a brass weight hangs on the other side of the rod for counterbalance. The rod is marked with dots as counters for weights. An object is weighed by putting it on the pan and moving the weight along the long arm of the rod. When the rod is exactly horizontal the weight of the object is indicated on the engraved scale on the rod. See this antique example in Singapore. Philvoids (talk) 10:58, 24 April 2022 (UTC)

Thanks! Yes I think that is what I was looking for. Some further searches turned up more examples, including this one on fleabay that has some good photos. I think the purpose of the multiple cords on top of the arm are to weigh heavier and lighter objects by moving the pivot closer to the load. I love the levelling needle on the one that you linked. I think I can concoct something like this based on the pictures. Wow! 2601:648:8202:350:0:0:0:4671 (talk) 16:11, 24 April 2022 (UTC)

Closely related is the "Pendulum Scale", which has a fixed counterweight. The advantage of this type of scale is that you don't have to fiddle around with the counterweights because they're fixed. I think the disadvantage is that they have fairly narrow ranges of weights they can handle. You mostly see them sold as pocket postal scales, because they're more portable than comparable digital models. ApLundell (talk) 00:14, 28 April 2022 (UTC)

Raindrops on eyelashes

When I see e.g. large green reflections from traffic lights due to raindrops on my eyelashes, is it diffraction, refraction or something else? Thanks. 212.180.235.46 (talk) 15:39, 24 April 2022 (UTC)

The droplets are rounded, so they act as lenses. which is refraction, and at that scale you are likely to see some diffraction, so yes. Abductive (reasoning) 17:26, 24 April 2022 (UTC)

April 25

Two types of snakes.

I watch animal and zoo stories on TV. Sometimes the staff begins to handle nonvenomous snakes. Example is Indigo snakes [2]. They are absolutely docile, never bite. How does the snake "knows" that it is not venomous? I also once observed a video whereas a young keeper opened a glass door of a highly venomous snake. The snake threw its entire body toward his arm and bit him. Obviously he ended up in a hospital. How do venomous snakes "know" they are so poisonous? Thanks AboutFace 22 (talk) 00:25, 25 April 2022 (UTC)

They bite their prey. Their prey dies. They eat. Clarityfiend (talk) 02:51, 25 April 2022 (UTC)

How do you "know" you have legs? How do you "know" you have a tongue? --OuroborosCobra (talk) 03:23, 25 April 2022 (UTC)

That's proprioception. --Jayron32 12:29, 25 April 2022 (UTC)

Without getting mired in questions of animal cognition, if we think of them as bundles of habits, the bitey habits evolved (or evolved away) along with the venom glands that make the biting effective. If a black mamba had its venom glands removed, I would expect it to continue trying to envenomate anybody nearby who it was tired of, at least to begin with. Possibly it could learn not to, in time, if the experience was unsatisfactory enough.  Card Zero  (talk) 04:18, 25 April 2022 (UTC)

You might as well ask, "How does a cow 'know' that if she munches on grass it will provide her with nourishment?". If she could talk, she might say, "Gee, I didn't 'know' that. I eat it because it is yummy."  --Lambiam 07:29, 26 April 2022 (UTC)

As a former keeper of snakes, I can assure you that at least some non-venomous snakes do bite. If a snake is acting docile and not biting when it's handled, it is more likely that it is used to being handled rather than some sort of self-awareness. Venomous snakes can also be trained to put up with being handled.[[3]] --Ykraps (talk) 10:16, 26 April 2022 (UTC)

Bow acceleration math

I don't know if this is a math or science question. I've been asked how fast does a bow accelerate when fired. By that, the question is asking how fast does the point where the arrow is notched to the string accelerate. This is about old bows, not fancy mechanical compound bows. Is there a change in acceleration? Doing some doodling, I suspect that the point of contact between the string and arrow changes speed in a sinusoidal manner. I simplified it to a diamond and looked at the change in length of the horizontal line as you increase angle of either side. That is a sine or cosine wave (depending on how you measure it). But, bows don't have a single vertex, so my guess could be completely wrong and the only reference book we have that has good bow information is A GLossary of the Construction, Decoration, and Use of Arms and Armor by Stone. It doesn't go into much detail about how the bow works. 97.82.165.112 (talk) 14:17, 25 April 2022 (UTC)

• First, the pedantic but correct answer: the acceleration of the bow string at the moment the arrow leaves it is zero, regardless of the bow mechanics. The acceleration starts positive, and the arrow will leave whenever it becomes negative, which means at the moment it crosses zero (acceleration being a continuous function of time for all practical purposes).

Obviously, one might ask about the speed/acceleration at other moments in time, and there some physics is required. In a spherical cbow-approach, the point where the arrow is notched does move in a sinusoidal manner. More precision may be obtained by a damped harmonic oscillator model, but I don’t think we care about that.

Let x be its position in the referential attached to the bow (where x=0 is the position at rest), the position varies as $x=L\cos(ft)$ where L is the draw length and f is the frequency of oscillation (times 2π if you want to be pedantic). The maximum speed reached is then $L\times f$ (and that is when the arrow leaves the string at x=0). The maximum acceleration is $L\times f^{2}$; that is reached at x=±L.

Two random archery websites I found (one, two) give the following values: draw length L is 30 inches (0.76 m) and arrow speed (when leaving) Lf is 400 feet per second (120 m/s) for a compound bow, 200 feet per second (61 m/s) for (I assume) the more standard stuff. Taking 300 feet per second (91 m/s) so I can do the calculation in my head, the maximum acceleration is 3000 feet per square second, or roughly 900 meters per second squared. That is roughly 100 times the standard gravity (i.e. the acceleration of a falling object without air friction). Tigraan^{Click here for my talk page ("private" contact)} 15:38, 25 April 2022 (UTC)

I'm going to quibble the claim that "the arrow will leave whenever [the acceleration of the bowstring] becomes negative". The arrow is being accelerated backwards by air resistance, so it doesn't leave the string until the string's acceleration reaches a sufficiently large negative value to match that effect. --Trovatore (talk) 19:33, 26 April 2022 (UTC)

First, how dare you being such a nitpicker, and second, how dare you beat me at that game! Tigraan^{Click here for my talk page ("private" contact)} 15:58, 27 April 2022 (UTC)

This site points out that speed claculations (such as those quoted above) usually assume a standard draw weight of 70 pounds (32 kg) and an arrow weight of 350 grains (22.6 grams). Bows, of course, come in a great variety of draw weights, youth training bows for example, are often only 15 lbs. Alansplodge (talk) 19:03, 26 April 2022 (UTC)

Thank you for the references. They are primarily about calculating arrow speed rather than acceleration, but it does appear that it is pretty much a sinusoidal acceleration. Initially, the arrow accelerates very slowly. The acceleration increases throughout the time that the arrow is fired. I doubt the inventors knew it at the time, but this action ensures that the arrow remains notched because the string is constantly pushing faster against it. 97.82.165.112 (talk) 10:19, 27 April 2022 (UTC)

See also Jerk (physics). {The poster formerly known as 87.81.230.195} 90.208.88.97 (talk) 12:33, 27 April 2022 (UTC)

Thanks. That got me to a reference, "On the of the Bow and Arrow," a thesis by Kooi. 97.82.165.112 (talk) 12:58, 27 April 2022 (UTC)

April 26

Is there a symbol for the "age" of something (e.g. age of the Universe, age of the Earth etc.)?

Hi everyone!

I was searching for scientific articles on the ages of certain things because I am a boring person with boring interests, such as the Earth and the oldest human fossil that we currently know of. However, I noticed that across these articles, there was no symbol for the age of the object in question. For example, the Planck 2018 results and this paper from Nature just give the ages of the Universe and some zircon crystals in Jack Hills, respectively, as "Age".

So far, I haven't been able to find any "official" source (e.g. IUPAC Gold Book, IUPAP Red Book) that gives an explicit symbol for the age of an object. Does anyone know if there is a symbol for this quantity, and, if so, the source (preferably from a well-known scientific body such as the IUPAC or IAU)?

Thanks :) — MeasureWell (talk) 02:44, 26 April 2022 (UTC)

The abbreviation "BP" (years Before Present) is sometimes used in archaeology or geology to indicate a number of years before the introduction of radiocarbon dating, nominally 1 January 1950. Philvoids (talk) 05:07, 26 April 2022 (UTC)

There are no symbols for height, weight or temperature either. Very few concepts that can easily be expressed as a word have a dedicated symbol. The diameter symbol ⌀ and cartographic symbols owe their existence to the use on drawings and maps.  --Lambiam 07:22, 26 April 2022 (UTC)

@Lambiam: Right, I was a bit unclear with the question, sorry about that. Let me clarify myself here: to take your example, according to the IUPAC Green Book and the IUPAP Red Book, the symbols for height, weight, and temperature are $h$, $G$ ($W$ and $P$ are also listed in brackets), and $T$, respectively. My question is this: is there an analogous symbol for the age of something (e.g. the Universe)? Thanks for the relatively quick response, and I hope this clears things up a bit. — MeasureWell (talk) 07:38, 26 April 2022 (UTC)

I see the present age of the universe most often represented by $t_{0}$ (e.g. here in Eq. 5.63). But that is at best an informal convention, and obviously $t_{0}$ can represent other things in different contexts. --Wrongfilter (talk) 08:13, 26 April 2022 (UTC)

@Wrongfilter: I do recall seeing that in the Review of Particle Physics ("Astrophysical Constants and Parameters") as well, actually, so I agree with you there. Still, my question (which is, admittedly, very difficult to answer) somewhat remains: is there an "officially recommended" symbol for this, or for the age of something in general? (If there is, I'm quite sure both of us would agree that it could do with being significantly easier to find ;) )

Thanks for the reply anyway – if worst goes to worst, I suppose that $t$ itself could work as a symbol. (I'm not planning to publish an article in a journal or anything, so its fine.)

long live $t_{\mathrm {E} }$ as the new symbol for the age of the Earth — MeasureWell (talk) 08:31, 26 April 2022 (UTC)

There is a unit: annum multiplied to megaannum or gigaannum with symbols Ma and Ga. Could also be yra Graeme Bartlett (talk) 07:24, 26 April 2022 (UTC)

Does eating snow dehydrate us?

Regarding an emergency with a person lost in the woods: I assume it might not be the best choice, since one is also trying to fight hypothermia, but would eating snow dehydrate us? The only plausible explanation to the common advice not to eat snow since it dehydrates the body is that using calories would make us also release water (maybe through breathing more heavily) --Bumptump (talk) 22:23, 26 April 2022 (UTC)

The main thing I've heard is not to eat yellow snow. A quick web search about dehydration from eating snow finds lots of hits with conflicting info, so I'm going to stay away from answering that one. But, if you have the means and fuel to melt the snow, getting water that way should be fine. 2601:648:8202:350:0:0:0:4671 (talk) 02:13, 27 April 2022 (UTC)

This is probably a confusion with Seawater#Human_consumption. Our article drinking says that In cold and frozen environments, some animals like hares, tree squirrels, and bighorn sheep resort to consuming snow and icicles. I don't know how those animals avoid freezing themselves in the effort to stay hydrated: calories and fur apparently suffice, but maybe they also need less water than humans - some animals can reduce water use (I forget how). In principle if a human is making a net gain of water by using calories to melt it (and has a backpack full of pemmican) then getting water from ice and snow ought to be viable, but you'd have to keep pausing to warm up, and keep eating small amounts of snow all day while remaining thirsty, and ignore the temptation to eat it faster, which sounds really annoying.  Card Zero  (talk) 02:41, 27 April 2022 (UTC)

"Burning" fat releases H₂O (about 1 mol per 150 kCal), which thereby becomes available to the body, so using calories hydrates us.  --Lambiam 05:34, 27 April 2022 (UTC)

Insignificantly so. A mole of water is 18 grams. 150 kCal is about the amount of excess calories you'd burn running about 2.5 km (1.5ish miles) or so [4], and you sweat far much more than 18 grams of water in that time period. --Jayron32 10:52, 27 April 2022 (UTC)

But it debunks the supposition for "the only plausible explanation" that using calories (not for running but to melt ingested ice) dehydrates the body.  --Lambiam 20:57, 27 April 2022 (UTC)

Water is water. I don't see how consuming water could cause "dehydration", although too much snow and ice could indeed risk hypothermia. --←Baseball Bugs ^{What's up, Doc?} carrots→ 11:36, 27 April 2022 (UTC)

April 27

Active volcano near Luxembourg

Around the midpoint of this article (in a, granted, unreliable source), there's an infographic depicting seismicity in Europe (captioned "Greece, Italy and Turkey are regions particularly prone to earthquakes") via an earthquake hazard map interspersed with triangles marking active volcanoes. Does anyone know which volcano (if any) the northernmost point close to Benelux refers to? It appears to be too far north to be Kaiserstuhl. Daß Wölf 13:50, 27 April 2022 (UTC)

Pretty sure this is the Volcanic Eifel, probably more specifically the caldera of Laacher See, which last erupted 12,000 years ago, and shows periodic low levels of vulcanism to modern times. See also Eifel hotspot. --Jayron32 14:01, 27 April 2022 (UTC)

Yeah, that seems to be in the right place, thanks! Daß Wölf 14:13, 27 April 2022 (UTC)

April 28

Flower name

Picture link

https://twitter.com/LavanyaBallal/status/1519524032655200256 --Ivan Tsar (talk) 03:51, 28 April 2022 (UTC)

Courtesy link to reported location: Cherkala. {The poster formerly known as 87.81.230.195} 90.208.88.97 (talk) 05:49, 28 April 2022 (UTC)

Possibly Amorphophallus paeoniifolium 41.165.67.114 (talk) 06:31, 28 April 2022 (UTC)