Wikipedia:Reference desk/Archives/Science/2007 January 21

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1 January 21

[edit] January 21

[edit] gallon challenge

is it possible to drink a gallon of milk within half an hour without throwing up? —The preceding unsigned comment was added by 129.123.214.24 (talk) 04:13, 21 January 2007 (UTC).

... or yogurt? Yes! -- Barringa 04:17, 21 January 2007 (UTC)

Don't know about milk, but you might want to read Water intoxication, which states that downing as little as 3 litres (0.79 gal) in a single sitting may prove fatal, as one woman has already proven recently. Clarityfiend 05:55, 21 January 2007 (UTC)

I believe this is extremely dangerous to do, as water intoxication will definitely set in and you will become sick. Throwing up is not an issue when either you die or need to be admitted to the ER. X [Mac Davis] (DESK|How's my driving?) 07:22, 21 January 2007 (UTC)

In general, remember that throwing up in these situations is good. Your body is trying to protect itself, and it normally does a pretty good job. Any time you try to "trick" your body, for example by trying to avoid throwing up even as you're downing excessive amounts of some toxic substance, is a time you've got to be worried that you might be tricking yourself right into your grave. (All too many college students belatedly rediscover this fact after extreme episodes of binge drinking.) —Steve Summit (talk) 15:53, 21 January 2007 (UTC)

I don't know about a gallon of milk, but I frequently consume a half-gallon jug with my meals in about 15-20 minutes. (Of course, I don't drink the milk all at once. I eat some, sip some milk, eat some more, etc.) — Michael J 18:48, 21 January 2007 (UTC)

Each human has their own unique tolerance to lactose levels. The amount you can consume without indigestion (or toxicity) will vary based on your previous diet, your health, and perhaps even genetic predisposition. You might try to eat a cup of yogurt to aid your digestion: though you will have more lactose, commercial yogurt often contains Lactobacillus acidophilus bacteria to assist your natural digestion of dairy. Of course, avoid self-harm by exercising common-sense limits. Nimur 21:30, 21 January 2007 (UTC)

After a couple of decades of eating cereal every day, I finally developed a strong aversion to all milk products. After about a year off dairy, I started eating ice cream again. After two, I'm back to a fair amount of butter and milk. So it seems your body can get overloaded with lactose over a long enough time, but it will 'reset' after a reasonable break. Vranak

The osmolality of milk ranges around 480 to 590 mosm/kg. It's not at all the same as drinking water. - Nunh-huh 22:47, 21 January 2007 (UTC)

It can be done - 2 kids on my swim team did. -- Sturgeonman 18:45, 23 January 2007 (UTC)

[edit] Supercapacitor research...?

I'm looking for any program that sponsors research into the use of supercapacitors for use as:

1.) an energy storage device for vehicles under 750 watts, and

2.) for capture and storage of random power generated by ultra high voltage sources, i.e, static electricity and in particular lightning.

-- Barringa 04:15, 21 January 2007 (UTC)

A related field is Photovoltaics or solar power. In a sense, most solar-powered vehicles use a battery (or capacitor) bank to store charge. To my knowledge, most of these are necessarily less than 750 Watts, because solar panels (on today's market) are usually less than this range (that would be between 5 to 10 industrial-strength panels, which would totally cover a very large vehicle). Consider the Stanford University Solar Car ? —The preceding unsigned comment was added by Nimur (talk • contribs) 21:34, 21 January 2007 (UTC).

The potential of solar power is 1000 watts per square meter. With sufficiently large value capacitors or batteries solar panels need not be on the vehicle but instead used to feed the grid from many locations. The advantage of capacitors for vehicles is in regenerative braking and other high power, short time span recharge instances where batteries are unable to recharge or discharge at the same rate or power level for the duration that capacitors can. This advantage also applies to capture of lightning and static electricity. Until solar panels are 100% efficient keep them on the farm. ☺ Barringa 08:46, 22 January 2007 (UTC)

1 kW/m^2 is the classical rule of thumb for total incident solar power flux on the earth's surface at airmass one. However, quantum conversion efficiency and practical factors limit the upper bounds of the power possible from pure photovoltaics. For a simple homojunction PV cell, the maximum efficicency is something around 30% for typical materials. The highest efficiencies demonstrated have been with so-called "tandem cells", which use several heterojunctions to maximize the wavelengths of light that can participate in the generation of an electron-hole pair. The best tandem cell I've seen had a conversion efficiency of about 30%. However, tandem cells are extremely expensive compared to cheaper options like poly-Si, so for most applications they are unsuitable. If memory serves, the best thin film poly-Si cells made to date are around 12% efficient at AM1, compared to 19% for multi-crystaline silicon and 25% for crystalline silicon. -- mattb @ 2007-01-24T23:56Z

It's not strictly related to your question, but you may be interested in the media buzz surrounding EEStor. --Robert Merkel 11:15, 24 January 2007 (UTC)

[edit] Length of an hour...?

Why is an hour 1/24th of a day and night and how long would a Moon or Mars hour be? -- Barringa 04:21, 21 January 2007 (UTC)

The article on hour contains an extensive history of the hour which contains answers to your question. The article on Mars states that the Martian day lasts about 1.028 Earth days - I'll let you do the units. The Moon is a little more complicated since it is orbiting the Earth. However, (correct me if I'm wrong), since the Moon is tidally locked with the earth, the sun should transit the lunar sky with the same period as the earth, so I would say a lunar hour is the same as an Earth hour. --bmk

The Moon is tidally locked, which means its day is the same length as its orbital period. They're both 27.3 Earth days, according to the Moon article. --Bowlhover 04:54, 21 January 2007 (UTC)

A day is (basically) a physical phenomenon: an earth day would be the same even if there were no humans. (to a close approximation.) An hour is a social phenomenon: 1/24 of a day, by social convention. The correct definition of "hour" for Mars was the subject of a lot of debate a few years back, and until we have a Mars colony, the debate is acedemic: the colonists will decide. For the moon, so far we have used the earth hour. The Lunar "day" is too long to use as a sleep-wake cycle, so moon colonists will almost certainly use Earth days and earth hours.

[edit] Osmosis

I was given the task of:

"Design an investigation to find out the effect of different concentrations of salt solution on the turgidity of cylinders of potato"

But how on earth can I test the "turgidity" of the potato cylinders? Thanks —The preceding unsigned comment was added by 203.198.23.69 (talk) 07:25, 21 January 2007 (UTC).

Assuming you look up what "turgidity" is, it seems that you need to setup an experiment to consistently measure each of the potato cylinders you put in various salt solutions. --Porqin 07:45, 21 January 2007 (UTC)

This is a common school experiment. See our article on osmosis and for example:

Note that teachers have access to the internet too so read the essays above, understand them, then write you own report. Do not copy and paste from them. Theresa Knott | Taste the Korn 08:51, 21 January 2007 (UTC)

Better yet, read them, do the experiment, write your own report, and cite the papers in your report. This tells the teacher that you did some literature search, which is an important part of any science project or experiment. It's not cheating, but rather the opposite. If you can make one of the experiments better (cheaper, easier, more precise, more repeatable) then you have a GREAT report: just state openly that you started with an expetrimental design you found in your literature search and what you did to make it better. -Arch dude 17:42, 21 January 2007 (UTC)

[edit] Nuclear

I have some questions about some ideas I have on how it could be possible to make a "sun" here on Earth. I would like to talk to someone live if possible because i don't know the lingo or have the mathmatical skills to work out the problems on my own?Evilsmurf213 09:58, 21 January 2007 (UTC)

Well, you can't literally make a "sun" on Earth, because the Sun is a vast ball of hot plasma many, many times larger than the Earth. It is possible to replicate, on a smaller scale, some of the thermonuclear reactions that power the sun. This happens in an uncontrolled fashion in a thermonuclear bomb. Doing it in a controlled and safe way is very difficult, and doing it in a useful way that generates more power than you put into the reaction in the first place is very, very difficult. To get an idea of the technical difficulties involved, see our excellent article on fusion power. Gandalf61 10:17, 21 January 2007 (UTC)

They did it in Spider Man 2 with tritium fusion. Tritium is a hydrogen isotope. How the movie presented it would be quite impossible, however the concept of a sun-like ball of plasma may be possible. Fusion power can give you more information on that. X [Mac Davis] (DESK|How's my driving?) 10:37, 21 January 2007 (UTC)

Today's best-guess implementations focus on magnetic confinement of the plasmas. Great effort has been spent on the theoretical requirements of such a machine; but many features such as controlling the confinement, the extreme environment (pressure, heat, high-currents), and massive electric currents and magnetic fields make this approach infeasible with 2007 technology. Nimur 21:40, 21 January 2007 (UTC)

Current technology can sustain a controlled fusion reaction for short periods. The Joint European Torus can achieve it for a few seconds, and ITER (under construction) is designed to generate 500 MW of fusion power for up to 500 seconds. What seems to be beyond current technology is to do this in an energy-efficient way, so that you can draw significantly more power from the reaction that you put into it. Gandalf61 00:03, 22 January 2007 (UTC)

[edit] The rusting of Iron compunds

Hello there,

I can not find anywhere the answer to the following question I came over in some past exam papers. Why does a tin-plated iron, when it is scratched at a certain point and the iron is exposed, rust at that point? But, why does a zinc-plated iron that is scratched hardly get any rusting?

Thank you —The preceding unsigned comment was added by 198.54.202.250 (talk) 10:17, 21 January 2007 (UTC).

It might have to do with how zinc has a lower reduction potential than iron. As a result, zinc oxidizes more easily than iron, and thus oxidizing agents will oxidize the zinc first, slowing down the oxidizing of the iron. On the other hand, tin has a higher reduction potential than iron, so the iron will get oxidized first. --Spoon! 12:29, 21 January 2007 (UTC)

See Galvanic anode . Tbeatty 15:03, 21 January 2007 (UTC)

Would the same apply to why rather use alluminium rivets two join two pieces of iron than copper rivets?

Copper is also very soft and malleable, so I don't know if I would trust it in a load-bearing rivet. Though aluminum is light-weight, it is significantly stronger (especially in the form of an industrial alloy). Nimur 21:42, 21 January 2007 (UTC)

[edit] Boltzmann distribution

I'm confused by the pages relating to the boltzmann distribution. Can someone clarify what the assumptions are in the model that is used as a basis for the distribution. (I thought it was that each energy state is equally likely and each distinct energy state is counted once?)87.102.44.44 12:41, 21 January 2007 (UTC)

[edit] science project question

i have made a fire alarm based on the priciple of the expansion of a bi metallic strip , i was wondering if i could make a smoke alarm out of it because you have to hold a candle under the bi mettalic strip for this to work(the one i made and i think it kinda stupid)212.72.15.225 15:09, 21 January 2007 (UTC)

Before we proceed, does your simple fire alarm work? If so, excellent! As a first step, something that actually works (even if it's not perfect, and even if it seems a little "stupid") is much, much more important than a theoretically better design that, however, does not work.

Smoke alarms are quite a bit trickier than heat detectors. Many of the real ones are based on an exotic radioactive reaction which is obviously out of the question for a school science project. However, another (simpler) kind of smoke detector works based on the smoke particles interfering with a beam of light. You can read much more about real smoke alarms in our smoke detector article.

You might be able to build a simple optical (light-based) smoke detector, using a light source and a photodetector. You can get a simple photodetector kit; they're another popular science project. You would want to arrange a photodetector and a light source on opposite ends of a mostly closed box. Then, you would want to adjust the photodetector so that it's very sensitive, so that it can barely decide whether to be "on" or "off". Then, you might be able to get it to detect smoke blown into the box, since the smoke would scatter some of the light and keep it from hitting the photodetector. Or, you could arrange it so that the light source normally did not shine directly on the photodetector, but the smoke caused some of the light to scatter and hit the photodetector. (That's evidently how the real ones work.)

In either case, it would probably have to be pretty thick smoke, and I don't know how you'd actually go about generating that smoke for testing, but it might work. (Ask for some help here: it would be really ironic if you accidentally started a fire and burned your house down while trying to generate smoke to test your home-made smoke detector with.) Good luck! —Steve Summit (talk) 15:40, 21 January 2007 (UTC)

Expanding on Steve Summit's thoughts:

Photoelectric detectors don't look "through" the smoke and expect the smoke to dim the passing light; this wouldn't be sensitive enough. Instead, they shine the light through empty space and the detector looks in at the passing light beam from the side. When no smoke is present, the light passes by invisibly and no light is scattered towards the detector. But when smoke is present, the smoke particles and the Tyndall effect cause some of the light to be scattered back towards the detector. Designed carefully, the detector won't see very much light at all when there's no smoke present and quite a bit when smoke is present.

But the real key to making a sufficiently-sensitive detector that doesn't care about slight changes in light level and slight electrical changes in the circuit is probably to use a pulsing light source and to amplify those variations in light seen by the phototransistor and maybe even synchronously detect the variations in light intensity. That is, use an LED as your light source and drive it from an oscillator that makes it flash at a certain frequency. Then design the amplifier to amplify just that frequency and (maybe) watch for fluctuations that are exactly timed with your pulsing light source.

Also, you can get aerosol cans of "test smoke"; local fire departments use this stuff to test smoke detectors and they can probably tell you where to get it. If you tell them about your school project, they might even give you a can or two.

Atlant 01:06, 22 January 2007 (UTC)

Wouldn't it be easier just have two phototransistor pointing at slightly different places, one visible to reflection of the LED when there's smoke while the other doesn't and just use an opamp to compare the two signals? Or something like a PICAXE to compare and sound the alarm using a simple programme? --antilived^{T | C | G} 02:53, 22 January 2007 (UTC)

hmm i got ur ideas , will do just that and ill try and fix a spraying device that will get acttivated along with the fire alarm to put off the fire

thanks 212.72.19.74 11:11, 22 January 2007 (UTC)

[edit] Meteor (?) near Geneva

This afternoon, around 2 PM local time, I saw what looked like a meteor while walking just east of Saint-Genis, France, just over the border from Geneva, Switzerland. It was south of me, moving roughly east-northeast. There were actually three distinct objects, all very bright and moving near each other, easily visible despite it being daytime. They looked kind of like the pictures of fragments of the Space Shuttle Columbia disaster (although they didn't leave trails), but there was nothing else visible in the sky to imply that it was debris from any kind of accident. Is there any news anywhere about what this might have been? If a meteor, how large and close would it have to be to be visible in the daytime like that? References preferred, but speculation is ok provided it's more educated speculated than I could make. ;) -- SCZenz 17:30, 21 January 2007 (UTC)

I saw something just like that over east kent a few months ago:) At the time I thought it could be a crashing aeroplane, or a UFO:) There are lots of things falling all the time, and of course something very small but close would appear brighter than something huge but far away:( You could ask at your local airport, see if they saw it too:)Hidden secret 7 17:50, 21 January 2007 (UTC)

It was likely very close—it was moving quite fast, and I certainly could believe it went just over the mountains, but obviously I didn't really have the proper reference points to judge. But I didn't think meteors made it to low altitude very often; it would still have to have been large at first. -- SCZenz 18:01, 21 January 2007 (UTC)

I have no clue what you saw, but what amused me was the "just over the border from Geneva" part. It's almost 280km from Geneva to Saint-Genis! You must come from a country where huge distances are the norm. ---Sluzzelin 21:15, 21 January 2007 (UTC)

Oops, I had the wrong Saint-Genis. It should have been [Saint-Genis-Pouilly]. -- SCZenz 14:39, 22 January 2007 (UTC)

I suspect it was a meteor that split into 3 parts, and was much farther away then you think. They probably did burn up in the atmosphere, as most do, after they went out of view. StuRat 05:58, 22 January 2007 (UTC)

Probably space junk! Most meteors arrive at very steep angles. It's a matter of probability: if you take pot-shots at a sphere, you'll tend to hit the "center," and only very few impacts will occur at the "outer edge." On the other hand, most manmade space junk is falling out of orbit and arriving with a nearly horizontal trajectory.--128.95.172.173 02:01, 24 January 2007 (UTC)

But don't forget the effect of gravity, which will draw meteors which otherwise would have missed the Earth into the upper atmosphere at a slight angle. StuRat 20:51, 24 January 2007 (UTC)

[edit] Speed of light and Relativity

I am a class 10 student so if i say anything wrong don't get cross

from what i understand Einstein's law of relativity says that nothing can travel faster than light.. it says something like if something approaches the speed of light, its mass will become infinite so it will take infinite energy to take it close to the speed of light...

^^ If I am wrong please correct me.

however, in the article http://en.wikipedia.org/wiki/Lightspeed (Speed of light) it says that:

"The blue glow in a nuclear reactor is Cherenkov radiation, emitted as a result of electrons travelling faster than the speed of light in water" - it is basically saying that electrons travel faster than the speed of light. my question is that since electrons are travelling faster than the speed of light (as mentioned by the article) isn't this a violation of Einstein's law or is the article wrong? Could you please explain in detail.. thanx

~~ MasterChief —The preceding unsigned comment was added by 202.84.36.64 (talk) 17:41, 21 January 2007 (UTC).

Relativity uses the speed of light in a vacuum:( In air, water, glass &c light slows down:) Therefore other particles such as electrons, which travel at close to the 'speed of light in a vacuum' are travelling faster than the light does in water:)Hidden secret 7 17:46, 21 January 2007 (UTC)

To amplify on Hidden secret's answer, the speed of light travelling through some medium (material) is equal to the speed of light in a vacuum divided by the medium's index of refraction. In water (index of refraction = 1.33), for example, light travels at 3·10⁸ m/s / 1.33, or about 2.3·10⁸ m/s. Small particles travelling faster than 2.3·10⁸ m/s (which is perfectly legal under relativity theory) and slower than 3·10⁸ m/s (which is the limit imposed by relativity) will show the glow of Cerenkov radiation. TenOfAllTrades(talk) 18:54, 21 January 2007 (UTC)

[edit] Ornithopters again.

A few days ago the only answer to a question about the size to weight ratio of an ornithopter was that it was very difficult to work out. So I have decided to try a different way of asking.

1 Does anyone know anyone that could help me with this?

2 Can anyone give me any advice on how to work it out? If I can get a little bit or information from a few people, I might be able to work out the rest myself.

3 Can anyone tell me how I can calculate the ratio from a smaller version, multiplying each value by a cetrain amount?

4 &c.Hidden secret 7 17:42, 21 January 2007 (UTC)

You could do tests with identical ornithopters (perhaps rubber band powered) at three scales, say 1X, 2X, and 4X, then plot the excess weight each can carry as a proportion of the weight of each test ornithopter. Next, run a curve through those test points and extrapolate the curve. You will find a scale at which the ornithopter won't be able to support any excess weight. You can then run some calcs to determine the projected weight the ornithopter could carry at each scale. StuRat 05:42, 22 January 2007 (UTC)

Unless you find a reference desk user who has not contributed to the Ornithopter article, one doubts if you are going to get much more in Wikipedia. The external links in that article, such as the University of Toronto ornithopter project and The Ornithopter Zone, look more promising, with pages for forums and questions. --Seejyb 08:36, 22 January 2007 (UTC)

[edit] Photons

According to E=mc², the energy is equal to the mass x the speed of light in a vacuum squared, but what if something that has no mass, such as a photon, is introduced to the equation. Shouldn't that come out to be E=0? That couldn't be true because a photon is a small packet of energy. Please explain what I'm missing here. :-) Imaninjapirate^{talk to me} 18:05, 21 January 2007 (UTC)

The popular equation is only part of the story. The full equation is $E = \sqrt{p^2c^2+m^2c^4}$ (where E, m, and c you already defined and p is the momentum). For a massive object at rest, this reduces to E=mc². But for photons (which can never be at rest because they always move at the speed of light) it reduces to E = pc, which is never zero. -- SCZenz 18:17, 21 January 2007 (UTC)

Ah, I see, thanks for the clarification. :-) Imaninjapirate^{talk to me} 18:28, 21 January 2007 (UTC)

how do get momentum though? both relativistic and no relativistic momentum requires rest mass?--137.205.79.218 00:47, 22 January 2007 (UTC)

Interesting. I didn't know the full equation either. --Proficient 01:34, 22 January 2007 (UTC)

The de Broglie hypothesis states that $p = \frac{h}{\lambda}$ , where h is the Planck constant and λ is the wavelength. For a photon of visible light, λ =~ 500 nm, so momentum = 1.325 × 10^-27 . Therefore, E in this case is about 3.972 × 10^-19 joules. This formula works for any wavelength of light. Laïka 11:10, 22 January 2007 (UTC)

Photons have no rest mass, true. But they're not at rest either. The above posts about momentum are correct, but another way of looking at it is to consider a hollow box with perfectly reflective interior that contains some (at least two) photons whose momenta add to 0. The resulting object has more mass than the box alone precisely in accord with

E = m c 2

applied to the photons' energy. However, the two effects (energy corresponding to mass and to momentum) don't stack because in the short formula m is relativistic mass while in the long formula it's invariant mass; these two are the same for an object at rest, but (again) photons don't do that. Alternatively, see the photon article's discussion of weird mass addition rules. --Tardis 22:40, 22 January 2007 (UTC)

[edit] Biology

Why is it difficult to formulate a simple definition of life? —The preceding unsigned comment was added by 72.89.196.47 (talk) 19:48, 21 January 2007 (UTC).

Because life isn't simple! In school we use MRS NERG - movement, respiration, sensitivity, nutrition, excretion, reproduction, growth. If it does all of those it's alive. Theresa Knott | Taste the Korn 20:00, 21 January 2007 (UTC)

But is it not alive if it doesn't meet all of them? Somehow I think in there lies the rub... --24.147.86.187 01:30, 23 January 2007 (UTC)

I recall an episode of Star Trek: The Next Generation that addressed this issue. When a crew member tried to define life, Data pointed out that fire met all the given criteria. Vranak

Formulating a simple definition for life is not difficult. What is difficult is coping with it. — Kieff 21:32, 21 January 2007 (UTC)

Fire fails the sensitivity test. A fire will move towards a forest if it's blown that way, but it doesn't know there is a good "food" source there. It's not alive. Theresa Knott | Taste the Korn 22:36, 21 January 2007 (UTC)

Well, a fire is certainly sensitive to a stiff breeze. I think selectivity might be a more accurate term. Vranak

Not wanting to get side-tracked here, but many phytoplankton are free floating as well. I don't know that selectivity/sensitivity to food is key to life. --TeaDrinker 02:12, 22 January 2007 (UTC)

It would be remiss to let this issue go without looking at what our article on life has to say:

[Life is] carbon-and-water-based, are cellular with complex organization, undergo metabolism, possess a capacity to grow, respond to stimuli, reproduce and, through natural selection, adapt in succeeding generations.

If I had to pick one fundamental property off that list, it would be adaptation. Failing to adapt means death. Vranak

Well, viruses and the prions which cause mad cow disease might be said to adapt and reproduce, but do just about nothing else that would define them as alive. Sunspots can exhibit many of the signs of life, as well (movement, growth, reproduction). Defining life as "carbon and water based" may exclude many alien forms of life. StuRat 05:21, 22 January 2007 (UTC)

Hard call on whether prions are reproducing. They certainly act as templates to change a conformation of other good proteins, but would you consider that reproduction since they are acting on a protein that was produced by another organism? Do prions adapt? There are no changes at the sequence level just conformation changes. Viruses on the other hand definitley reproduce their DNA or RNA although they need the help of another organism and obviously adapt. David D. (Talk) 07:22, 22 January 2007 (UTC)

For that matter, how about chain letters, especially the online variety, which can grow and mutate and reproduce, with the more successful mutations surviving and the less successful dying out. So, are they alive ? (Sure, they need people to survive, but don't many living parasites also need hosts ?) StuRat 22:34, 23 January 2007 (UTC)

See, that's my point. For the most part of our history, we regarded life as a magical, mysterious thing. We even thought only live things could generate organic molecules. Nowdays, from a strictly scientific point of view, life is but a collection of atoms moving about in a certain curious way. There's nothing physically or chemically special about it anymore, and that's why most definitions of life fail: because people are not willing to give up the idea that life is "special" and fundamentally defined by a single, special aspect (oh yeah, see soul for the most popular one.) Movement, respiration, sensitivity, nutrition, excretion, reproduction, growth. By this definition, early "pre-life" on Earth wouldn't be alive. They were just chemical replicators, without feeling, senses or respiration. You may ask yourself, is this reproduction? I say yes, it is, because their numbers increased by their own means. Was the capture and processing of random chemical substances nutrition and excretion? Opinions will divide this case, but I also think yes, it is nutrition and excretion. Isn't it basically the same thing that happens with modern life? Just because we're complex wrappers for basic molecular behaviors doesn't mean we're any better than initial life on Earth. We're more complex, but that's it. So in a way, I believe we are, in fact, just unwilling to decide ourselves. We want life to be special, we want it well defined on its own, when it is, in fact, just another spectrum of the natural workings of our Universe, like so many other things we've encountered so far. If I had to come up with a definition of life, it would just be something like "an unitary, chemically isolated entity of matter that has the ability of chemical self-assembly and self-replication." A virus wouldn't be alive, since it is unable of self-assembly or self-replication (it needs to hijack something that does.) A prion wouldn't be alive either, it can just modify existing entities. Nor would be a crystal, because its units are not chemically isolated. (is there any form of modern life that's not isolated?) The important thing is, if you want to come up with a definition, it has to be a line that divides everything in two groups. The subjects won't change because of the definition, so whatever definition you pick is largely irrelevant, but at least you made up your own mind about what to call them, and that's as good as it gets. Just make a decision and deal with it. — Kieff 10:09, 22 January 2007 (UTC)

Lots of living things don't meet these criteria:) Men can't reproduce, and many people choose not to but are still alive:) Some things don't adapt, but haven't become extinct:) And they think life doesn't have to be carbon based, we just haven't found anything that isn't yet:) Just because something hasn't been done, it doesn't meen it is impossible:]Hidden secret 7 18:58, 22 January 2007 (UTC)

"Lots of living things don't meet these criteria" -> you're using "living things" against a definition of living things, without presenting yours (in fact, it looks like you're assuming you have one that is implicitly "the right one")... The point of my definition is that our cells are alive. We're just a collection of cells, so we're obviously alive as well. The question now is, what defines a multicellular organism? This is also important, but at least you've got the basics of "life" covered. — Kieff 21:52, 22 January 2007 (UTC)

A simple defenition of life: Anything that is alive:]Hidden secret 7 20:20, 24 January 2007 (UTC)

[edit] You can eat it, or throw it away...

I have an apple that has turned to a giant bruise and is started to leak liquid that smells like vinigar. Can I mash it up and incorporate it into banana bread? --Seans Potato Business 20:16, 21 January 2007 (UTC)

What have you to lose by just giving it a try? Make a small batch and see what it's like. ny156uk 20:30, 21 January 2007 (UTC)

Taste a bit - If as I imagine it will taste vile then you will have your answer.87.102.33.178 20:51, 21 January 2007 (UTC)

If it were me, I'd just cut out the affected area. Vranak

That would leave me with the stalk! :) --Seans Potato Business 22:03, 21 January 2007 (UTC)

How expensive are apples in the place that you live? In most places, one bad apple is usually an acceptable, replaceable loss. Consider composting the bruised apple, (so that nothing is wasted) and buy a fresh one. Nimur 21:48, 21 January 2007 (UTC)

Throw it into the garden. Apples seem to be a blackbird's favourite food - whatever condition they're in. --Kurt Shaped Box 22:07, 21 January 2007 (UTC)

Blackbirds! They have leaves and soil to eat. What about me?! Could it potentially make me ill? Even if the are things in there fermenting it, they're adapted to survive in cold apples right, and I'm a warm person? --Seans Potato Business 22:32, 21 January 2007 (UTC)

Hmm botulism bacteria are adapted to live in poorly canned corned beef tins. They are dangerous to humans, not because they attack the body directly but because , while living in the can , they make a toxin. Theresa Knott | Taste the Korn 22:41, 21 January 2007 (UTC)

I've eaten badly bruised apples many times. They never seem to have done me any harm. Ditto for brown bananas - they look nasty and are a bit mushy but they taste fine. --Kurt Shaped Box 22:50, 21 January 2007 (UTC)

Well I've done it now. I've pushed the button and there's nothing left to do but wait... and wait... (will report back) --Seans Potato Business 23:13, 21 January 2007 (UTC)

What did it taste like? Theresa Knott | Taste the Korn 23:23, 21 January 2007 (UTC)

It's not disimilar from my usual banana bread. Sweet, a bit tougher than usual (but I don't measure the time (or even the ingredients accurately) so my results vary a lot anyway. The mixture didn't rise as much as I'd have liked but maybe there wasn't enough baking powder. As always, I had the problem where a skin forms as the outside of the bread cooks first and then the inside mixture expands and bursts out like some sort of cancer, trying to reach the back of the oven (not a very asthetically pleasing bread). I think being toucher makes it easier to cut small slices though. It's quite moist. I'm rather pleased with it... and if I don't get ill or die then all the better. :) --Seans Potato Business 00:07, 22 January 2007 (UTC)

Please stop eating the bread and throw it away. Thanks. Hipocrite - «Talk» 04:26, 22 January 2007 (UTC)

Heh...heh...heh...they think I'm CRAZY. But I know better. It is not *I* who am crazy. It is not I who am MAD! Didn'tcha hear 'em? Didn'tcha see the CROWDS? Oh my beloved apple loaf...how I love to lick your creamy center! HOOOWWWWWW... ...and your oh-so-nutty chocolate covering! You're not like the others...you like the same things I do! Waxed paper...boiled football leather...dog breath...We're not hitchhiking anymore! We're RIDING! --Seans Potato Business 11:09, 22 January 2007 (UTC)

Seans, I appreciate your enthusiasm, but we like to keep an air of decorum here at the Reference Desk. When things descend into whimsy and joking, it drives people away ^{[citation needed]} ^{See last September/October}. Thanks. Vranak

Sorry... --Seans Potato Business 07:26, 23 January 2007 (UTC)

Feed it to your least favorite son 69.150.209.15 21:19, 22 January 2007 (UTC)

[edit] When the gulls are eating together

What do those cackles, squawks and gabbling noises mean when they're all close together eating? --84.71.105.35 22:17, 21 January 2007 (UTC)

Probably just general chit-chat. You wouldn't be overly concerned about the details of an Italian family sitting down for a boisterous meal, and I see little reason that gulls' squawking and gabbling would be much different. Vranak

Sometimes they seem to squwak at others telling them to "back-off, this is my food" if food is scarce, but otherwise it seems to mean "Food!! Food HERE!!!"... Or maybe just the imagination of a bored school boy watching gulls eating food scraps... :p --antilived^{T | C | G} 02:44, 22 January 2007 (UTC)

[edit] Antihypertensive Foods?

Are their any foods or supplements that naturally act as a mild antihypertensive? -Quasipalm 22:45, 21 January 2007 (UTC)

Did you read the article you linked to? See http://en.wikipedia.org/wiki/Antihypertensive#Herbals_provoking_hypotension although do note that the list lacks citations. Theresa Knott | Taste the Korn 22:51, 21 January 2007 (UTC)

[edit] adrenal glands

what is affected if the adrenal glands are removedDrizzit1966 i think it is the urinary system but a friend says the reproductive system. who is right? -- Kelly

Have you seen our article on the adrenal gland? It does play a role in the reproductive system in that it produces several sex hormones, that's about the biggest link out of those two. Primarily though, it produces the bodies corticosteroids and adrenaline, which is neither urniary or reproductive. Vespine 02:52, 22 January 2007 (UTC)

I believe most glands are categorized in the endocrine system, even if they serve functions in other processes. Nimur 03:47, 22 January 2007 (UTC)

The effects are described in the article on Addison's disease. You will have to follow the links to understand most of the terminology used, and the few I have followed do explain the terms adequately, so you should get your information. Both kidney function and reproduction are affected, though the latter is not discussed in the article, except to mention that pregnancy may lead to a lethal Addisonian crisis. --Seejyb 05:55, 22 January 2007 (UTC)

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