Wikipedia:Reference desk/Archives/Science/2007 September 29

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September 29

Venusian atmospheric pressure

The earth and venus have aprroximately the same size, but venus has about 90 times the atmospheric pressure of earth, why's that? —Preceding unsigned comment added by 88.203.105.128 (talk) 00:14, 29 September 2007 (UTC)

There is 90 times as much gas in the atmosphere - which makes it push down 90 times harder. Venus' gravity is a little less than Earths - but that's made up for by the fact of much the atmosphere being almost entirely CO2 - and CO2 is heavier than Oxygen and Nitrogen. SteveBaker 00:40, 29 September 2007 (UTC)

Best place to start...Atmosphere of Venus. It has a history section, bits that suggest that it may have been more earth-like in the past. ny156uk 00:41, 29 September 2007 (UTC)

using electrical appliances in Israel

Please help me. What kind of plug or adaptor do O ineed on appliances to use in Israel? And does Israel use 240 or 120v?… Bonnie Ralph bonnie.ralph@btinternet.com —Preceding unsigned comment added by 86.142.73.24 (talk) 07:33, 29 September 2007 (UTC)

Looks like you need a "European" adapter, as Israeli sockets take type H or type C plugs. See our article domestic AC power plugs and sockets. Hopefully someone else here will have hands-on experience and can tell you more.--Shantavira|^{feed me} 07:52, 29 September 2007 (UTC)

Mains power systems has some info also.

Penny battery - another wild and sovereign funded idea

The penny is no longer made of solid copper but of zinc encased in a copper foil. Would the savings in material cost of recyclable copper and zinc oxide justify the energy that could be produced (for powering personal electronic devices, etc.) by using a redesigned coin with one side made of zinc at 90% total coin thickness and the other side made of copper at 10% total coin thickness so the end user could stack the coins between pieces of blotter paper saturated baking soda solution? Clem 10:27, 29 September 2007 (UTC)

The biggest and best savings would be to stop making the damned things. Your information is outdated, there is now less than 2.5% copper in a penny - the rest is zinc. The trouble with making batteries out of them is that it's a lot of hassle to mess around with blotting paper and baking soda - and the resulting battery wouldn't fit in anything that takes regular batteries. But worst of all - your pennies would have to be zinc on one side and copper on the other. If the mint believed that people would accept such a coin, they'd make them zinc on both sides - 100% zinc - and save more money. Since a penny costs a lot more than a penny to make - that's an important thing! But the best reform of all would be to simply stop making them. SteveBaker 16:00, 29 September 2007 (UTC)

(Actually - you might be right about the 10% copper thing - I was assuming you were talking about US 1c coins - you probably mean a UK 1p coin or something.) SteveBaker 16:04, 29 September 2007 (UTC)

The OP is presumably not referring to the British one penny coin, which is of copper-plated steel. Algebraist 19:23, 29 September 2007 (UTC)

Yes, I am referring to the US penny. At 1.5 volts per coin I could stack 9 (8 blotter inserts) and get 12 volts. ...Just thought of something. You can cause a piece of steel wool to ignite by using it to short a 9 volt battery. So if you fell out of a plane and landed safely near some salt water and had some pieces of cloth to use as a blotter substitute and had a pocket full of the new, lets call them energy pennies, and had a piece of steel wool then you could make a fire and stay warm until a spotter plane saw the smoke - all because the government invested in energy pennies. Cool. Clem 01:17, 30 September 2007 (UTC)

• And if you had some ham, you could have ham and eggs, if you had some eggs. --Sean 15:47, 30 September 2007 (UTC)

• (outdent):::::A pocket full U.S. one cent coins in the possession of a McGyver quality artificer on a desert island could be made into a battery of respectable voltage and of very modest current output. By using a flat rock to grind away the copper coating from the edges and one face, a stack of these separated by paper or thin pasteboard soaked in a conductive solution (brine, etc) could be assembled to produce the required voltage (say 12 volts to power a small radio transmitter whose battery is dead, lost, or unsalvageable). But the output current would be very small due to the small area of a cent. Early 19th century batteries used zinc and copper, but the pieces were typically many times the area of a U.S. cent, like several square inches. Several penny voltaic piles could be paralled to increase the current output. I built such a penny battery, after reading this question, using 100 grit sandpaper as a surrogate for a flat stone, to expose the zinc on 2 pennies, leaving the copper on the head side (obverse). With a piece of paper soaked in lemon juice between them, I saw an open circuit voltage of about 0.4 volts and a short circuit current of about 25 microamperes (this was an old crappy analog multimeter, so the numbers are approximate). I checked the current draw of a small instrument powered by 2 AAA batteries, and it was 2 milliamperes, so it would have taken about 8 of these units to get the voltage and about 80 in parallel to get the current to run even a low power instrument that doesn't light up, move, or transmit messages. Various alternatives for such Galvanic cells might just use aluminum (such as from a boat or plane) as one electrode, covered by cardboard or paper soaked in a conductive liquid, with a number of intact pennies covering the top of the cardboard, to increase the area, then a piece of aluminum on that followed by the cardboard, pennies, etc to get both the current and voltage needed. Sand could be used to remove any paint, etc., from the aluminum. Edison 20:11, 30 September 2007 (UTC)

Has somebody access to this article on Earthdoc?

Hi, I hope this is the right place to ask (please forgive me if it isn't): Can someone with access to Earthdoc (meaning someone who is member of the European Association of Geoscientists & Engineers) please send me an article (PDF 2,13MB)? The text Geophysical Investigation of the Nasca Lines by A. Weller, K. Hartsch, S. Rosas, G. Reppchen (2006) seems to published nowhere else. Concerning its content, the website says: "The content on this site is provided without charge as a service to members, to be used for information and educational purposes only." So, I would welcome a EAGE member willing to inform and educate me in this respect :-) Yours, --Jonas kork 12:28, 29 September 2007 (UTC)

Buffers

What shifts in the following reactions may occur in the event of addition of a) H+ ions and b) OH- ions.

NaHCO3 ↔ Na+ (+) HCO3-

H2O ↔ H+ (+) OH-

H+ (+) HCO3- ↔ H2CO3 —Preceding unsigned comment added by 89.242.33.223 (talk) 12:44, 29 September 2007 (UTC)

Maybe look at Le Chatelier's principle. Someguy1221 17:27, 29 September 2007 (UTC)

Human eye frames per second

Just as video cameras have a certain number of frames per second that they can record, does our eye have a certain number of frames per second that we can process? I'm assuming this must be true because if we see something going very fast we see it as a blur. If it is true, than about how many do we see per second? Would this number change throughout our life? One of the reasons I find this so interesting is because if our FPS is lower, we can comprehend less things per second, and therefore our perception of time might seem to go faster, and vice versa. Imaninjapirate^{talk to me} 14:47, 29 September 2007 (UTC)

This question seems to get asked every few months. See for example Wikipedia:Reference desk/Archives/Science/2007 January 16 and persistence of vision.--Shantavira|^{feed me} 14:56, 29 September 2007 (UTC)

Certainly check the archives - we've discussed this to death in the past. The short answer is "No, the human eye doesn't have a 'frame rate'". It just doesn't work like that. Using our peripheral vision (which is most sensitive to time-varying information) we can see things flickering at maybe between 30 to 100 Hz - it depends a lot on the individual and on the ambient lighting conditions. I know that in an otherwise utterly dark room I can reliably see flicker at 72Hz and I can reliably NOT see it at 76Hz - but other people have different limits a few don't see flicker at 30Hz and I met an unfortunate chap who can't watch TV or operate a normal computer because he can see flicker directly in front of him at over 100Hz! That indicates some limits on minimum 'response time' - but that's not at all the same thing as 'frame rate'. SteveBaker 15:37, 29 September 2007 (UTC)

Does anyone else see flicker after the source is removed? It's sort of like a dynamic version of staring at a yellow and green picture and then switching to a white background and seeing blue and red. If I turn off a tube TV in a dark room, I will see a flickering image that is square and TV sized that persists in my main field of vision for quite a while longer. It's not a definable image, just a flickering rectangle. Chemical persistence doesn't seem to explain this. --DHeyward 08:37, 1 October 2007 (UTC)

I can only see flicker while it's present, but I haven't actively tested my "persistence of flicker". BTW, I can see flicker of 70Hz, but not 75Hz in peripheral. —Preceding unsigned comment added by 203.22.236.14 (talk) 09:25, 1 October 2007 (UTC)

I think it's very possible that you still "see" flicker after it's gone away. Our brains are good at cancelling out unchanging distractions. So you stop 'hearing' the 'shhhhhh' noise of the fan of your computer and only notice that it was ever there when you turn it off. For a moment, the silence seems somehow more silent than a mere absence of sound - it's almost like there was 'anti-sound' (bear with me here!). There are also those 'illusions' where you stare for 30 seconds directly at a US or UK flag that's painted in cyan, black and orange instead of red, white and blue - then you look at a blank page and see the flag mysteriously floating there in it's normal red/white/blue colours...those work the same way. Your eyes get bored with looking at orange and cyan and 'cancel them out' - so when you look at a white sheet - you see the complements of those colours ("anti-colours") for a few seconds until your eyes adapt to the change. I think it's possible you could be doing the same thing with the flicker - except that when the flicker goes away you are seeing 'anti-flicker'. Dunno - but it seems plausible. SteveBaker 14:33, 1 October 2007 (UTC)

Renaming proteins after discovery of function(s)

Does anyone else feel that scientific things and processes should be named according to what they do? I note that people refer to such names as unimaginative but as a student, I find them so much easier to remember. I hold the highest respect for scientists who name their discoveries after their function etc, instead of slapping their name or something on it. I know that a protein's function isn't always known at the time of discovery but is it unfeasible to rename proteins as their functions are established? Sonic hedgehog is probably characterised well enough to rename it, right? Am I the only one that gets fustrated? I envision some organisation like IUPAC, renaming proteins for the common good... IUPAC did it with chemicals, and we all survived. This isn't just a rant; ideally someone would say "yes, we all agree and <<acronym>> is already making progress in doing exactly as you describe". It's probably just me... —Preceding unsigned comment added by 201.220.222.140 (talk) 20:22, 29 September 2007 (UTC)

I suspect that at some point most proteins will exist within a standardization system such as the one for enzymes. There are some relatively young efforts to categorize all proteins (see List of types of proteins, Gene Ontology) that should eventually lead to ways to develop standardized names....hopefully names that will reflect function. In the case of enzymes, it is often possible to identify a single active site that defines the function of the enzyme. However, in the case of many other proteins there are multiple binding sites on the protein and it is often not a trivial matter to define "the" function of the protein. For some types of non-enzymatic proteins, groups of scientists sometimes get together and propose a standard nomenclature, but so far it is not unusual for the proposed standard nomenclature to be ignored by other scientists. It might be educators who have to step in and push for sensible names rather than wait for working scientists to do it. (external links: a wiki thesaurus for gene and protein names, Gene and protein nomenclature in public databases). --JWSchmidt 17:26, 29 September 2007 (UTC)

As a student, you are frustrated by this, but as a reasearcher, you will soon find the opposite source of frustration: After some lengthy discussion, some phenomenon has been finally named somehow but for some reasons you want to study the discussion that ed to this naming and locate the research papers involved in it. What do you use as search term if you look for old articles from a time when a name was not yet established and everybody just wrote "that strange phenomenon that occurs in X, Y and Z, and hes been described by, among others A, C, D, and F? Then, you'll be happy if the name that the first researcher proposed simply stuck. But you might be pleased to hear that recently on a conference of geneticists, a resolution was passed urging scientists to stop using too flamboyant gene names, because --so they argues-- that may be funny with fruit flies but becomes embarassing with the equivalent human genes. No doctor would want to have to say: "I am so sorry, but your baby seems to suffer from a sonic hedgehog mutation." Simon A. 18:06, 29 September 2007 (UTC)

The problem with this suggestion is that proteins do not have a single function. For example, what should one call Adrenocorticotropic hormone? It can act through a number of different receptors to influence many different biological processes. As it happens, it was named after the process that was first discovered. In addition, protein families to provide information about their phylogenetic relationship. Consider the 800+ olfactory receptors in mice. Each one will bind a number of different odorants with higher or lower affinity. Currently a numerical nomenclature is used based on chromosome cluster (and hence phylogeny) and order. Even if we knew all the odorants that even one receptor can bind (and we don't) exactly what would we call it? This is one example, but the principle hold true for pretty much all proteins. At very best all we could do is name than after one of the functions we happen to know they have. Rockpocket 04:32, 30 September 2007 (UTC)

Nitrogenous polysaccharide

What elements, other than nitrogen, make up the nitrogenous polysaccharide capsule of prokaryotik cells? Thanks alot 88.110.203.63 16:31, 29 September 2007 (UTC)

see polysaccharide -- Flyguy649 ^talk _contribs 16:36, 29 September 2007 (UTC)

Thanks alot, thats just great, i got mixed up with amino acids, and started thinking there may be an 'r' (variable) group, wich can contain sulphur as well, but im just dumb, your not :) thanks again, 88.110.203.63 16:48, 29 September 2007 (UTC)

(me again, wow i just read your user page flyguy, and read you are studying amino acids, and i dont think its geeky at all) —Preceding unsigned comment added by 88.110.203.63 (talk) 16:50, 29 September 2007 (UTC)

Pupil size

Is pupil size a genetic trait? I know some people whose pupils are like pinheads in sunlight and other people whose pupils are like planets at night time. Are there any advantages/disadvantages to having smaller/larger than average pupils? --Candy-Panda 16:49, 29 September 2007 (UTC)

First of all, the pupil size of a single healthy individual has a wide range (about a factor of 4 in diameter, or 4 stops in photography jargon). Therefore it doesn't make sense to talk about "pupil size" itself as a genetic trait, but it does make sense to ask about the heritability of minimum or maximum pupil size. This study found that maximum pupil size after mydriasis has a heritability of up to 80%, so it has a strong genetic component. Here's an important quote:

This study only examined final pupil size, and so it cannot be certain whether the strong genetic influence is on actual maximum pupil size or on the response to mydriatics. Bertler and Smith's previous twin study found a high MZ [monozygotic] correlation for initial pupil size and no difference in the rate of dilatation between MZ and DZ [dizygotic] twins, suggesting that the genes determine mydriasis not in response to drug or dose, but determine the maximal possible size of the pupil.

I couldn't find an analogous study for the minimum size of the pupil.

The advantages of small and large pupils are exactly the same as those of large and small f-numbers in a camera, with the additional consideration that if you're in bright sunlight too often and your pupils aren't small enough, the ultraviolet does long-term damage to your eyes. —Keenan Pepper 18:06, 29 September 2007 (UTC)

I knew this girl who's pupils were always dilated - had to wear sunglasses when out Think outside the box 12:12, 4 October 2007 (UTC)

• As far as advantages and disadvantages go, smaller size makes you more suitable for laser vision correction and less prone to halos.

STOP YOUR BODY'S MELANIN PRODUCTION

is there something that can stop your body from producing melanin in hair —Preceding unsigned comment added by 81.99.212.22 (talk) 18:34, 29 September 2007 (UTC)

The short answer is no. -- Flyguy649 ^talk _contribs 20:26, 29 September 2007 (UTC)

With all respect, no matter how many times you ask the same question, albeit phrased slightly differently, you are going to get the same answer. There is no safe way one can change one's hair colour permanently. Rockpocket 04:17, 30 September 2007 (UTC)

Come now. Surely it's well known that aging or stress can stop melanin production in hair. —Tamfang 08:08, 30 September 2007 (UTC)

Aging and stress are not safe, though. And I think it would be nice if someone produced a post regarding the reason why the original poster would like to know that, which seems to be to become a white person. It is not healthy for one to wish to become a white person, since this is impossible. I believe that, if the original poster wants to become a white person, they ought to look for a psychologist. A.Z. 08:16, 30 September 2007 (UTC)

I don't see anything about safety in the OP, do you? If I asked "is there something that can cause skin to become red and itchy" would you say "No" because poison oak is unhealthy? Tsk. —Tamfang 16:09, 30 September 2007 (UTC)

The poster didn't make it explicit that they want something safe. No, I wouldn't say no to that question about the red and itchy skin. A.Z. 19:25, 30 September 2007 (UTC)

?Stress, Tamfang are you sure about that. I know it's a popular myth that stress turns your hair grey or white but is there any scientific evidence? I have serious doubts that stress can affect your hair colour although this idea has been perpetuated in many films. As the colour is dictated by the growth of the hair in the follicle it is likely to take many weeks to change the colour of a sizeable strand. I will accept that nutritional stress may cause a change in hair colouration , as seen in pellagra or beri-beri.Richard Avery 13:17, 30 September 2007 (UTC)

Yes, we all know that any change in your metabolism won't be visible in your hair until it has time to grow out, nobody here implied otherwise. —Tamfang 16:09, 30 September 2007 (UTC)

Ok, for the sake of hypotheticals, it may be possible using genetic tricks. This is not possible currently in humans. Disrupting the melanin biosynthetic pathway throughout the body would likely not be good for you, since many other molecules your body needs, such as some neurotransmitters, are produced by the same (or related) pathways. Also, melanin is really important in the eye to prevent excess light reaching the retina. Albinos have poor vision in part because of a lack of melanin. And remember that melanin is important for the protection from UV damage in the skin. Back to the question. The trick is to block the creation of melanin only in hair; this could be done using a virus that would deliver DNA coding for small interfering RNA sequences that would disrupt the production of melanin synthesis enzyme or enzymes. If such DNA was under the control of a hair-specific promoter, it would only disrupt melanin production in hair follicle cells. I don't think it's likely that you'd be able to "hit" all the cells in all the hair follicles, so you'd still likely end up with some coloured hair. Also, even if all hair melanin production were stopped immediately, that would only affect new hair; existing hair would still be coloured until it grew out. You'd need to bleach it to remove the colour in older hair. -- Flyguy649 ^talk _contribs 15:44, 30 September 2007 (UTC)

• There seems to be an ever-increasing amount of money being spent by cosmetics companies in an attempt to find ways to alter melanin production and storage. Such efforts are of interest to the US government because there are important health implications of research aimed at providing tools that could be used to change to melanin production and storage. Here is a recent article that mentions some existing melanin research directions: Regulation of Skin Pigmentation via Modification of Tyrosinase Function. --JWSchmidt 17:21, 30 September 2007 (UTC)

Funny, I want to darken my skin. I live in Australia and of Irish ancestory, so every summer it takes a couple of months to tan sufficiently to avoid quick sunburn. I envy a darker skinned Sri Lanken person I work with who has never suffered sunburn. Wouldn't it be nice to be able to adjust one's skin colour to the environment in which they live. --203.22.236.14 09:19, 1 October 2007 (UTC)

A recent study from Australia: Nle4-D-Phe7-alpha-melanocyte-stimulating hormone significantly increased pigmentation and decreased UV damage in fair-skinned Caucasian volunteers.
--JWSchmidt 21:14, 1 October 2007 (UTC)

Swappin' spit reagents

Frequently in journal articles, I read about experiments being performed with reagents sent as gifts from other researchers. I was wondering what limitations there are in this practise? If I buy mice, I'm allowed to breed them for my own use but not allowed to send them to other researchers. What about expression vector plasmids for example? Are some unpatented? Perhaps the research community would benefit from some sort of network/website through which scientists could swap reagents more easily. I suppose some big companies might oppose this... --Seans Potato Business 18:53, 29 September 2007 (UTC)

As a condition of publishing in peer reviewed journals, one usually has to agree to make one's reagents available for other scientists. There are limits to this, obviously, when the materials are very expensive or rare or commercially available for purchase. That said, some scientists will resolutely ignore any requests for materials (not that I'm bitter or anything...) but most will make an effort to provide materials at no cost when asked. Since many novel materials may have commercial, value most institutes, universities and companies will make your sign a material transfer agreement, which can limit your use of the gift. The most common limit is that you will not pass the material on to anyone else and that your relinquish the rights to any commercial application you may stumble upon. MTAs have to go through the legal and/or technology transfer department of your institution, so an online swap-meet would probably not work.

When you purchase plasmids from companies, you usually agree to a limited license of use, which restricts you from copying the plasmid and giving it to others for free. Like in the computer software industry, this is the way producers ensure they recoup profit from their work. Rockpocket 04:08, 30 September 2007 (UTC)

"...And the clueless newb was enlightened" :) Do you say that I can't take my plasmid and copy it so that I never have to buy more of it or just that I can't copy and give to someone else? --Seans Potato Business 17:55, 30 September 2007 (UTC)

You can amplify plasmids as much as you want, they would not be of much use otherwise. This right could probably be restricted for commercial applications, but I doubt that this happens a lot. As long as you don't make money out of selling the plasmid directly you are by all means on the safe side. Cacycle 19:10, 30 September 2007 (UTC)

Andrew Ryan would disagree. -Wooty [Woot?] [Spam! Spam! Wonderful spam!] 08:16, 1 October 2007 (UTC)

How to choose best undergraduate school for best mcat scores

Hello, I am going to attend undergraduate university next year. I searched for statistics of students who take the MCAT from certain undergraduate schools to compare undergraduate programs, but could not find any results. Is there a site/listing of the best programs that prepare students to take the MCAT exam?

Thanks, Robert —Preceding unsigned comment added by 71.56.231.40 (talk) 20:27, 29 September 2007 (UTC)

Honestly, I'm a little dubious about the idea of picking your undergrad location based on average standardized testing scores of graduates. I think as a metric that is likely to be highly unreliable, and will have little guarantee of giving you, the individual, high MCAT scores. --24.147.86.187 21:35, 29 September 2007 (UTC)

If your goal is to do well on the MCAT, start experiencing what you need to know now. Go to a hospital and volunteer (especially in the emergency room). Classes and studying are necessary, but they don't replace experience. -- kainaw™ 00:19, 30 September 2007 (UTC)

Pick a university where you think you will be happy. If you are happy, it will be easier to put you best efforts into your studies. ike9898 17:29, 30 September 2007 (UTC)

Resistor capacitance

Any estimates for the capacitance of a metal film resistor with a body length of 6mm? —Preceding unsigned comment added by 88.110.150.148 (talk) 21:32, 29 September 2007 (UTC)

Is there anything written on it? --Mdwyer 23:05, 29 September 2007 (UTC)

A 1/4 watt resistor has about 1/2 pF of residual capacitance according to the first link in this search. - hydnjo talk 23:07, 29 September 2007 (UTC) Amended to fix link. - hydnjo talk 23:22, 29 September 2007 (UTC)

For a specific inidivual resistor, you should measure the capacitance. If you are designing for production, you should use the manufacturer's spec sheet. Resistors are typically manufactured for a specific tolerance in resistance, so the tolerance in capacitance will typically be much larger. Your circuit design should therefore accommodate the entire range of possible capacitance values from the manufacturer's spec sheet. -Arch dude 23:44, 29 September 2007 (UTC)

130.15.208.183 08:32, 30 September 2007 (UTC)

Contact Lenses and Frothy Solution

I have begun to notice that whenever I apply solution to my contact lenses, (for example after removing them from the case, just before I would put them in my eyes) the solution frothes up and many small bubbles form. Does this indicate some sort of reaction taking place, or that the lenses are very dirty?

The good sign is I haven't gone blind, even if this does indicate something, since I still put them in. But, I was just wondering, since it only started happening recently...

Thanks, Eclipse45 22:01, 29 September 2007 (UTC)

They, I mean we, don't do medical advice here. The reason is obvious when you think about it. Sorry. --Milkbreath 22:50, 29 September 2007 (UTC)

Most contact lens solutions have a consumer help telephone number on the label. You should immediately call this number for an answer to your question. If you are not completely satisfied by the information you get over the phone, you should immediately contact your eye-care professional. Do this now. Do not delay. -Arch dude 23:33, 29 September 2007 (UTC)

(In response to the comment of Milkbreath) The way I read it, the question is about chemistry, not health. --71.175.68.224 02:31, 30 September 2007 (UTC)

It's borderline; that's why it's still here. She mentions going blind from a chemical reaction on her contact lenses, however facetiously. That's medical in addition to chemical. Suppose someone here tells her not to worry about it, and she actually does go blind from it. Don't say it can't happen; you're not an eye doctor, and neither am I. I'm tempted to remove it even now, but her intent clearly was not to ask a medical question, and, to judge by her user page, she's at least relatively sane. --Milkbreath 03:19, 30 September 2007 (UTC)

Contact lens mentions cleaning and disinfecting fluids. Then look up Hydrogen peroxide.Polypipe Wrangler 02:52, 30 September 2007 (UTC)

Ok, first of all, DID I say I was a she? Where did you get that from? And second of all, you can notice I said the good thing was I DIDN'T GO BLIND, AS IN A JOKE, that nothing did happen to me even when I still put the contacts on afterwards, after noticing the froth.

And yes, for the record I asked about the chemistry involved. Maybe the 2nd part of the last sentence was unclear, but, the rest I think is fine. Learn to read. And yes, I know it says not to ask medical advice.

Thanks for the whole fiasco. If I was blind, could I see the screen to type that question? Think about it. 130.15.208.183 08:32, 30 September 2007 (UTC)

We are supposed to assume good faith in Wikipedia. I did. And all caps is considered shouting. Don't shout. I haven't. Flinging insults invites a flame war. We don't do that here (though I, personally, think they're tons of fun). We have to be nice, dammit. So. I had a fifty-fifty chance with the sex. Why should there be a problem with a gender-neutral "she", anyway? As for the going blind, you haven't gone blind, yet. But that isn't the issue. I don't know how to put it any clearer than I have. There was a medical aspect to your question. You expressed concern for your safety. If the froth had appeared on your car instead of on something you put in your eyes, that would be different. Blindness is no joking matter, by the way. We couldn't tell whether you were joking or whether you had any sense at all because we don't know you, but we're learning fast. --Milkbreath 14:28, 30 September 2007 (UTC)

The chemical reaction is the decomposition of hydrogen peroxide into water and oxygen:

2 H₂O₂ -> 2 H₂O + O₂

I believe this reaction occurs quite slowly spontaneously, but quite quickly in the presence of the catalyst catalase, contained in protein deposits on your contact lenses.

Incidentally, blind people can use computers, via screen readers and other technologies. StuRat 11:46, 30 September 2007 (UTC)

Indeed, Jack Vance (for example) has cranked out a handful of novels since he lost his sight. —Tamfang 16:14, 30 September 2007 (UTC)

Ok, so then, as you put it milkbreath, there does seem to be a medical aspect to my question (i swear i never thought of it like that when I typed it), but just the same, i wanted to know about the chemical aspect, which others have answered. as for insults, no I didn't want to cause anything, nor am i particularly nuts. I just got a bit angry to see that instead of answers I got a bunch of 'don't seek medical advice' - which in retrospect follows with wikipedia policy if you saw my question in a medical light. in any case, i'm sorry for anything that did happen: heat of the moment thing? but i did get an answer so i'm still content. 130.15.208.183 17:49, 30 September 2007 (UTC)

Sorry for the slow response; I missed your reply. No hard feelings. I know only too well how easy it is to get, or make someone, exasperated in this medium. My rule is "Shit is a dish that is best served cold", if you'll pardon my French. That applies literally, too, come to think of it. --Milkbreath 15:40, 1 October 2007 (UTC)

Who, me? :o --froth^t 06:23, 4 October 2007 (UTC)