Wikipedia:Reference desk/Archives/Science/2007 January 1

= January 1 =

...and drink plenty of fluids
The advice "get plenty of rest" when you are sick I can understand - this would allow the body to devote more of its resources to fighting the infection (and I imagine there are some other reasons too). But what is the purpose of saying "drink plenty of fluids"? BenC7 11:07, 1 January 2007 (UTC)


 * At the risk of giving medical advice, I would suggest that two of the reasons are (a) because if you get a fever you may sweat a lot and lose lots of fluids, causing your cells to become dehydrated and probably more vulnerable to attack from pathogens, and (b) because more water flowing through your body helps flush out toxins that may accumulate either as a result of infection or your own immune response. (a) seems more valid to me, but I'm not a doctor so I'm not 100% sure. Confusing Manifestation 12:42, 1 January 2007 (UTC)
 * Avoiding dehydration. See the article for more details. Carcharoth 16:44, 1 January 2007 (UTC)


 * And also, diarrhea may cause dehydration. StuRat 16:43, 1 January 2007 (UTC)

I've currently got a cold - and I need lots of liquid because of the amount of 'stuff' I'm coughing up/coming out of my nose.. Though I do seem to need to drink more than I'm apparently losing.87.102.14.212 18:45, 1 January 2007 (UTC)


 * Basically, it's something your doctor can tell you to do while you wait for your immune system to do its job. The likelihood that your thirst will stop working and you will get seriously dehydrated because of a cold is near zero if your brain works. Unless you have dysentery (severe diarrhea) you will have no problem maintaining hydration by drinking when thirsty. The toxin explanation is early 20th century American folk medicine: no one has ever demonstrated any such phenomenon as "flushing toxins" though plenty of alt med quacks make a living on the concept. alteripse 03:25, 2 January 2007 (UTC)

sulphur in eggs
I know that eggs contain lots of sulphur, and therefore smell of hydrogen sulphide, but I was wondering what form this sulphur was in inside the eggs, weather it was just sulphur, or hydrogen sulphide, or as amino acids. 172.142.71.239 11:33, 1 January 2007 (UTC)
 * I imagine some sort of iron sulfur protein, in which case it would be in the sulfide form, or specifically would probably come from a cys residue which contains a sulfide, an egg is after all, a biological system. I could be completely wrong of course, I'm not a chicken chemist--71.247.246.54 12:57, 1 January 2007 (UTC)


 * In a fresh egg the sulfur is bound in organic molecules (mainly proteins), and you shouldn't be able to smell it. It is only when the organic matter is broken down by bacteria that foul-smelling hydrogen sulfide is produced. The sulfur-containing amino acids used in the formation of proteins are cysteine and methionine. —The preceding unsigned comment was added by Lambiam (talk • contribs) 19:29, 1 January 2007 (UTC).


 * I think one should eggspect a fowl smell from chicken eggs! —The preceding unsigned comment was added by 88.109.92.168 (talk) 01:55, 2 January 2007 (UTC).

control &c.
Apparently some people can learn to control how fast their heart beats, even though this is supposed to be subconscious. Are there other things like this people could potentially control, and what would the limit of this sort of control be? —Preceding unsigned comment added by 172.142.71.239 (talk • contribs)
 * Meditation. I used to be able to control my pulse rate, haven't practiced in a while--71.247.246.54 13:40, 1 January 2007 (UTC)


 * You can also learn some control over brain waves and skin temperature. There is some info at biofeedback.--Shantavira 13:43, 1 January 2007 (UTC)


 * Also blood pressure. The limit of control over autonomic systems would probably be resting levels or slightly lower. I doubt that any amount of practice could enable someone to raise their skin temperature to 105 degrees, or slow their heart rate to zero, or lower their blood pressure to below healthy levels. *The article also mentions pupil dialation and sexual arousal.* Anchoress 03:33, 2 January 2007 (UTC)

magnets
Is there anything that can be put in front of or around a magnet, to stop things being attracted to it? Like plastic can be wrapped around a wire &c.172.142.71.239 13:28, 1 January 2007 (UTC)
 * Wrapping plastic around a wire with an active current doesn't have any effect on the magnetic field it produces, see also current--71.247.246.54 13:38, 1 January 2007 (UTC)
 * Superconductors have interesting magnetic properties, however I'm not sure if they would be usable in the way you suggest. TERdON 13:43, 1 January 2007 (UTC)

You may complete magnet to a ring with some magnetic material. Therefore, magnetic lines of the magnet will be gathered mostly inside the ring, and there "amount" in air would reduce. Magnetic suspectibility may amount to thousands, so it's the factor in which you can effectively reduce the attracting force, it seems.

What about a screen, cutting off constant magnitic field? Yes, a superconductor of 1st kind would help. But it needs temperature less than 20K. ellol 14:39, 1 January 2007 (UTC)
 * The best thing we have for magnetic shielding is Mu-metal. --Zeizmic 16:04, 1 January 2007 (UTC)

How about a diamagnetic material.87.102.14.212 18:18, 1 January 2007 (UTC)Such as glass or plastic.87.102.14.212 18:43, 1 January 2007 (UTC)


 * I thought about this a lot, I don't think there is such a thing becasuse if there was I can think way to make a perpetual motion machine. Vespine 21:59, 1 January 2007 (UTC)


 * Diamagnetic material wouldn't help, because usually its magnetic susceptibility is tiny fractions of 1. ellol 01:18, 2 January 2007 (UTC)

Does a Faraday cage stop magnetic waves? What if there's a current running through the cage? Would that be electromagnetic shielding? Will electromagnetic shielding block magneticism? magnetism?--Kjoonlee 15:49, 2 January 2007 (UTC)


 * A Faraday cage will only block the EM field down to some lowest frequency (which depends on its construction). A steady (~dc) magnetic field would not induce any current in the metal of the Faraday cage and so would not be "bucked" (cancelled).


 * Atlant

You can place more magnets on either side in a specific pattern which will almost cancel the magnetic field on one side, see Halbach array.EricR 17:27, 2 January 2007 (UTC)

Just like how a Faraday cage works for EM field, a cage made of a good magnetic (ferromagnetic ?) material should be able to act as a magnetic shield. I suppose that a magnet placed in such a cage will not attact things outside the cage -- WikiCheng | Talk 06:42, 3 January 2007 (UTC)

Catastrophal global warming through release of gaseous compounds from ocean floors
Read a newspaper article in 2006 which described a potentially catastrophic release of gaseaous compounds from the floor of the world's oceans. Stored (how?, when?) in the ocean floors, they are held there by a combination of pressure and cold temperature there. The prognosis was that when the oceans became warmer, through global warming, they would be released; causing a rapid rise in the greenhouse effectand a rapid atmospheric temperature rise resulting in extinction of all life. This article was not referenced in any way (names, institutions, etc.); and its negative effect on me led to ´my not searching for more info at that time.

Question: Does anyone know more about this? Is it a real threat, or just someone's idea of how to have fun scaring people? —Preceding unsigned comment added by 81.229.41.91 (talk • contribs)
 * To be honest, you might get a better response at Talk:Global warming--71.247.246.54 14:19, 1 January 2007 (UTC)
 * Also, Runaway greenhouse effect might answer your question--71.247.246.54 14:23, 1 January 2007 (UTC)
 * If you ever get extremely interested in it, I can have you talk to a friend of mine that is an expert in such area. These stored gaseous compounds are clathrate hydrates, mostly methane clathrate. See the Clathrate-gun hypothesis, for our closest article to what you are looking for. Happy new year! X [' Mac Davis '] ( DESK | How's my driving? ) 16:02, 1 January 2007 (UTC)

ITs the damn lakes u know, they release CO2 in toxic amounts stored in them. cuz there was no flow of water so it stayed underground, until the pressure pushed it up, and killed people. read it somewhere on Wikipedia Black Sea you will find it from that article. somewhere. --Judged 08:40, 6 January 2007 (UTC)

Polymaths needed!
The lists listed at Lists of basic topics need to be proofread for ommissions. Please choose one or more that you are familiar with and browse them to see if any holes or gaps pop out at you. If they do, by all means, fill them in! The Transhumanist17:37, 1 January 2007 (UTC)
 * Some basic topics don't have any subtopics! I'm adding them! X [' Mac Davis '] ( DESK | How's my driving? ) 20:35, 1 January 2007 (UTC)
 * What's the difference between "Physics Scholars" and "Leaders in Physics"? Clarityfiend 08:16, 2 January 2007 (UTC)
 * Those were just part of the template that was substituted in using the subst command. They work for some of the lists, but in those which they don't provide the best fit, simply replace with whatever does.  Like "Famous physicists" or what not.    The Transhumanist14:49, 5 January 2007 (UTC)

coke
How come if I pour coke into a cup it goes really all fizzy whereas if i pour it into glass it is less fizzy? — Preceding unsigned comment added by 86.128.220.133 (talk)
 * It depends on how you define "cup". It probably has something to do with (possibly) nucleation sites on the cup's surface, which don't exist on smooth glasses. Just a guess, though. I could be totally wrong. PTO 19:02, 1 January 2007 (UTC)
 * I think that's fairly accurate. Vranak


 * Interesting. You could try pouring some into a squeaky clean glass and some into a dirty glass (eg fruit juice residue) to test this. Make sure both glasses are dry to start with.--Shantavira 20:16, 1 January 2007 (UTC)
 * Unlikely to give good results with fruit juice residue. There's likely to be leftover acids on the surface which will completely taint the result (put a slice of lemon into your coke to see the effect). --OliverH 10:08, 6 January 2007 (UTC)
 * Pour it slowly into a coffee mug, or pour it quickly into a plastic cup. Nucleation and agitation produce different effects. X [' Mac Davis '] ( DESK | How's my driving? ) 20:34, 1 January 2007 (UTC)
 * I'm not sure this is at all related but I've done some experiments before in a glass: basically, I think, the more organic matter in the water, the smaller the bubbles. Are you using the same bottle/can of coke in each cup/glass? And as a quick note, shake the coke first, to make sure that the concentration is even, rather than the liquid being more concentrated at the bottom of the bottle than the top. Cheers! Yuser31415 20:58, 1 January 2007 (UTC)

If you pour water in the cup then throw it away before pouring in the coke, you shouldnt get as much fizzing. Better still, try it with beer.

I read recently that nucleation caused by flaws in the surface of the container is, in fact negligible, and the main cause is particles on the surface. 80.169.64.22 19:29, 3 January 2007 (UTC)


 * You mean dirty glasses? —The preceding unsigned comment was added by Light current (talk • contribs) 20:49, 3 January 2007 (UTC).