Wikipedia:Reference desk/Archives/Science/2006 November 11

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November 11

Paper Mache

What is an easy way to create paper mache using newspaper and masking tape? I can't seem to find any methods on Google. The final product will be used to support weight. (It is a chair. The base can only be 200 square centimeters touching the floor.) --Proficient 02:59, 11 November 2006 (UTC)

You can certainly tape a lot of newspaper together to support weight, but that is not what papier mache is at all. StuRat 02:22, 11 November 2006 (UTC)

You don't need tape to create paper mache. Just get a bowl and fill it with glue. Rip up strips of newspaper, and throw them in the bowl. Then, paste these strips of newspaper onto whatever surface you want them on. --Bowlhover 02:33, 11 November 2006 (UTC)

Perhaps I should make my question clearer. I want to make a paper mache like substance only using newspaper and masking tape. (kind of like liquefied masking tape) How can that be done? I cannot use glue. Maybe paper mache is not the correct word to use. How would I go about compressing newspaper then taping it efficiently? Sorry if my question was vague, because I am asking this question on behalf of my sister. Thank you. --Proficient 03:02, 11 November 2006 (UTC)

You could shred and wet the newspaper and compress it into the forms you want, then once they're good and dry you could wrap them in masking tape to fasten them together and help them keep their shape. Anchoress 03:41, 11 November 2006 (UTC)

What is wrong with glue? Note that you are not supposed to use the kind of glue that children or hobbyist use to glue paper together. this stuff is to sticky and dries to fast: you cannot model. For paper maché, you use the old-fashioned kind of glue which one uses to affix wallpaper to walls. It's a dilute liquid stuff which sticks only mildly to your hand, so that you can easily mix a bowl with this glue with paper shreds and start sculpting. (If my dictionary is right, English really lacks proper terms to describe the different traditional kinds of glue, such as the kind of glue, we are talking about here, and which is called de:Kleister in German. The German wikipedia article says it is a mixture of water and either methyl cellulose or starch. Usually, you buy it in DIY stores as a powder and mix it with water.) See also methyl cellulose#glue and binder. Simon A. 11:13, 11 November 2006 (UTC)

From memory, you can make it by cooking cornflour with water. Other flours would probably work as well. Also, I used to call it something and not glue. Possibly gum glue or gum paste or something. You could buy it in a small tub (already made) in Malaysia and this stuff tended to work better (I think) and last longer then homemade stuff (not sure whether it was that different or just had presevatives of some kind). This page may be interesting [1] Nil Einne 15:02, 11 November 2006 (UTC)

Kepler

What is the title of the book that has a clear discription of Kepler's discovery that spherical balls do not fall straight down from the edge of a table? The chapter's discussion points out how Kepler put ink on the balls to determine trajectory distances on a piece of paper he laid out on the floor. The discussion goes on to point out that the notion of trajectory made him ask the question, "what if the ball's trajectory flew past the edge of the earth?" Writer1 02:38, 11 November 2006 (UTC)

A question on the biology of free will.

If the brain is a chemical machine, and all physical objects -- including neurons -- adhere to a system of laws, isn't it possible to predict the future behaviour of a person based on the billions of minute events occurring in the brain? Doesn't this imply that there is no such thing as free will? (I have very little education in psychology or neurology, this is merely something I'm curious about.) —The preceding unsigned comment was added by Pesapluvo (talk • contribs) 03:12, 11 November 2006 (UTC)

Well, you've got some pretty big if's in there, depending on what you mean by "a system of laws". Modern physics, at least in some interpretations, is not completely deterministic -- see interpretations of quantum mechanics. However, even if quantum indeterminacy can show up at the neuronal level, behavior that's unpredictable merely because it's random is not what most metaphysical libertarians would consider to be "free will". For true free will, there does seem to need to be some non-physical part of the story, such as a soul. --Trovatore 03:35, 11 November 2006 (UTC)

No, because so much of human behaviour consists of reactions to outside stimulii. It might be barely possible to predict a particular person's reaction to a particular event. Anchoress 03:43, 11 November 2006 (UTC)

You might as well ask if free will is an illusion cause by imperfect knowledge or ask how can you tell if reality is real - how do you know you aren't really a brain in a jar being fed artificial stimuli of a 'reality' totally different from your actual 'true' reality. You don't have a way of knowing, as there is no testable difference. Robovski 04:37, 11 November 2006 (UTC)

We have a featured article on free will, and it has sections on perspectives of various scientific disciplines on the subject. --Allen 04:41, 11 November 2006 (UTC)

If there is an apparently "random" element, some would suggest that this random element is directed by the "soul" of the individual, thus providing free will. StuRat 06:09, 11 November 2006 (UTC)

Considering random, there is the quantum level, and random events can and do happen there. Perhaps the soul lies in the strings? Robovski 06:16, 11 November 2006 (UTC)

See the articles Determinism and Free will. In thinking about this issue I have always found it an unsurmountable problem to give a working definition of "free will". However, whatever the definition, I don't get why people think that true quantum randomness can save a concept of "freeness" of the will under assault by determinism.  --Lambiam^Talk 20:44, 11 November 2006 (UTC)

I don't think that's the claim. The point is not that quantum randomness constitutes freedom, but rather that, since the outcome of a quantum interaction is not determined, there is an opening for an agent-caused outcome without violating any physical laws. For a simple example, imagine a situation in which QM tells you that a neuron may fire, or not fire, with probability 1/2. The agent's choice causes it to fire. Looking at it from the outside, you can't establish that the agent has manipulated physical reality, because it might have fired anyway. --Trovatore 20:56, 11 November 2006 (UTC)

Refractive index of cellulose

What is the refractive index of cellulose? Chickenflicker 03:43, 11 November 2006 (UTC)

You should try a google search. It depends on what exact cellulose polymer, cellulose is 1.5400; Cellulose nitrate is 1.5100; Methyl cellulose is 1.4970; Ethyl Cellulose is at 1.4790. Other polymers rmosler 15:55, 11 November 2006 (UTC)

Supernova

If there was a supernova at the centre of the Milky Way (which is obscured by dust in optical wavelengths), how bright would it appear? Let's say the Pistol Star turns into a supernova. Since all but a billionth of its light is blocked by dust, can we even see it without a telescope? --Bowlhover 06:25, 11 November 2006 (UTC)

Don't know about optical but Super-Kamiokande would certainly see a neutrino shower. Maybe it would also trigger LIGO? -- Rwst 11:43, 11 November 2006 (UTC)

Yes, you would be able to see it without a telescope

How bright (what magnitude) would it be? --Bowlhover 20:24, 11 November 2006 (UTC)

It depends on the type of supernova. If it were a type 1a it would have a magnitude of about -19.6 (they all have very similar magnitudes). Type 2b supernovae vary quite a lot.

Hmm. So at the distance of the Pistol Star (25 000 light-years), a Type 1a supernova would be 587 503 times dimmer than magnitude -19.6, which is magnitude -5.2. But since only a billionth of the star's light is not blocked by dust, the supernova would appear to be magnitude 17.3. Is that correct? --Bowlhover 03:03, 12 November 2006 (UTC)

I don't think that's right. A difference of 5 magnitudes corresponds to 10², so a billionth would be a difference of 30, not 22.5. It would be magnitude 24.8, not 17.3, and you'd need a pretty powerful telescope to see it. Clarityfiend 05:05, 12 November 2006 (UTC)

After reading about the pistol star, it would definately be a type 2b supernova rather brighter than -20. Where did you get the idea that all but a billionth of its light would be absorbed?

The "difference of 30" is using the big billion. Nobody uses those any more. :-)

Billion still usually means 10¹² in Australia. JackofOz 23:09, 12 November 2006 (UTC)

I also think that the factor of a billion must be seriously exaggerated. This abstract gives the extinction as only about 3.5 magnitudes for the Pistol Star, meaning that about 1/25 of the light comes through.

The distance of 25,000 light years is 776 times the reference distance for absolute magnitudes, so the brightness would be 1/776² or about 1/600,000, corresponding to about 14.5 magnitudes. With an extinction of 3.5 magnitudes added to this, a supernova of absolute magnitude -21 (for example) would have an apparent magnitude of -3, similar to a bright planet.

(However, I am not saying that is the correct absolute magnitude, nor that the extinction of 3.5 is correct for the galactic center as opposed to the Pistol Star.)

--Anonymous, 11:15 UTC, November 12.

According to the abstract: "We estimate an extinction of A_K = 3.2 +/- 0.5 using the near-infrared colors of the star". The dust blocks infrared light much less strongly than it does visible light. According to this, even the best telescopes cannot see the Pistol Star in visible light. Assuming the best telescope is the Hubble (with a limiting magnitude of 30), then the star would be 30-4=26 magnitudes fainter than if there was no dust. 26 magnitudes translates to 25 billion times.

According to http://www.strw.leidenuniv.nl/events/phdtheses/messineo/chapter1.pdf (halfway down the page on page 10), the visual extinction rate towards the galaxy's nucleus is 30 magnitudes, or a trillion times. This website seems to agree. --Bowlhover 15:02, 12 November 2006 (UTC)

In that case I stand corrected. --Anon, 00:30 UTC, Nov. 13.

Could science achieve this in the future?

As you probably know, your brain stores all the information, knowledge and memories you have acquired since birth.

In the future, would it be possible for scientists to dissect the brains of dead people to uncover the information, knowledge and memories the deceased have acquired during their lifetime?

There would be endless possibilities if this could be achieved. For example, if someone was murdered, scientists could dissect their brain and find the part which stores memories of their murder, and hence find out who was the murderer. If there was a fast food chain with a secret recipe very few people knew, and one who knew the recipe died, scientists could dissect their brain and find out the secret recipe.

Yes, it's possible, some day, but the far more important value would be the ability to reproduce the mind of the dead person in a computer. StuRat 08:26, 11 November 2006 (UTC)

If your mind can be recovered, are you really dead? I don't think memories from dead people will ever be recoverable, however it may be possible for live people to transfer memories electronically at some point. --Tbeatty 08:41, 11 November 2006 (UTC)

I seriously hope it is and will remain science fiction. I also think it will never be possible, as the information in the brain is probably not stored as text and images but instead by complex connections and relations between personal experiences, memories, and emotions. –Mysid☎ 09:04, 11 November 2006 (UTC)

The brain is not a very well-understood organ. We know a lot about it, but there's also so much more about the human brain/mind that we do not know. Questions like this become almost a matter of personal philosophy. I for one, believe that everything you are is in the phyiscal brain, so that there is no spiritual 'mind', 'spirit' or 'soul' aside from what the brain generates. Therefore, i would say the answer to your question is yes. I believe with the rate biology is advancing, there will be a point in the future where we will have the ability to take a phyiscal brain, and in effect 'extract' everything the person whom the brain belonged to knew. To replicate all the connections of a biological brain with technology. I suppose, this ultimately means (for someone with my beliefs at least) that the person isn't really dead, because everything that made him/her who he/she is is in the brain. And then from there, speculation becomes fantasy.

A quote of interest here, which i remember but can't remember were from, went something like this "If our brain was simple enough for us to understand, then we would be too simple to understand it." Perhaps it's true we may never achieve that level of understanding regarding how our own minds work? And i would imagine, advances in technology allowing people to 'extract' knowledge from another person's brain would be highly contraversial, brining to life entire new ethical and moral issues. So i guess it really isn't something we can expect in the near future after all. --`/aksha 10:34, 11 November 2006 (UTC)

• I disagree. No individual human may understand all the workings of a brain, but collectively, and with the aide of computers, we may. A much simpler device, like a car, is understood well enough by all of us collectively to construct, optimize, repair, and use it. However, few individuals likely understand every aspect of everything that happens to make a car operate. Your auto mechanic, for example, probably has no idea about the chemistry and physics behind combustion, he just knows what the proper air-fuel mix is to get the most power out of the engine. And the physicist who does understand all the theory may not know what the acceptable clearances are for the cylinder. StuRat 20:20, 11 November 2006 (UTC)

• To be honest I think the original contention "...your brain stores all the information, knowledge and memories you have acquired since birth" is highly unlikely, and certainly unproven. Thus further discussions are mere speculation. And even if there was some validity to the argument, tracing the neural pathways of specfic thoughts and memories would seem to be extremely difficult, if perhaps not necessarily impossible. I also suspect these would degenerate VERY quickly after death. --jjron 14:01, 11 November 2006 (UTC)

• Decomposition would certainly destroy the memories stored in the brain, and freezing might, as well. But, that would give scientists a few days to work, perhaps enough time with some future technology. And embalming might preserve the memories indefinitely. StuRat 20:13, 11 November 2006 (UTC)

To uncover any type of information it will almost certainly involve an electronic device. Whether our brain saves things as "text messages" or as complex relationships, we will have to use some device that could create a database of these "text messages" or complex relationships in order to decipher them and store our who knows how many memories/information/knowledge. It would be a monumental task to locate and decipher a particular memory if in fact it's possible. Also, in the case of dead people, you would have to take into account decomposition of the brain.

• Too little is known about the physiological basis of memory to even know for sure what types of analogies and metaphors are worth considering for this. All of the above text assumes the brain behaves something like a digital computer which seems highly unlikely to me. An analog computer, maybe, but even then I think one is going to have to work pretty hard to come up with a metaphor which doesn't mislead. --24.147.86.187 01:33, 12 November 2006 (UTC)

And now for the lazy answer. Check out Determinism, Transhumanism and Mind transfer. DirkvdM 09:55, 12 November 2006 (UTC)

Long term memories and things that are learned can be represented by relationships between physical neurons in the brain, if the extremely complex relationships could be measured and interpreted, then maybe some part of memory or experience could be deciphered. BUT thoughts and feelings and short term memory are more like complex patterns of electrical impulses firing amongst an even more complex web of already established neural connections, these cease upon death and so I doubt there'll ever be any way to 'recover' them after someone has died. When you think about it, those electrical impulses could very well prove completel integral to the entire process, without them it may not be possible to interpret anything at all from the established physical brain. Vespine 00:01, 13 November 2006 (UTC)

I believe your current thoughts are electrical impulses, not your memories. If all your memories since birth were in a continuous loop of electrical impulses, you would need a nuclear reactor to provide the power needed. Furthermore, brain scans show that energy is only used in a few specific areas, while most of the brain is "turned off", when not in use. StuRat 21:12, 13 November 2006 (UTC)

A possible confusion here is that English uses the word 'memory' for both storage and retrieval (although 'recollection' and 'remembrance' are alternatives for the latter). DirkvdM 05:59, 14 November 2006 (UTC)

The human liver and the break down of alcohol

How is it that the human liver is capable of breaking down so much alcohol? Where in human evolution did our liver become so effective? I don't see anthing that would cause prehistoric man to become specialzed such as having a high alcohol diet. Alcohol dehydrogenase. Ed Dehm 07:24, 11 November 2006 (UTC)

The article you provided says that the bacteria in the digestive tract produced alcohol which was toxic and needed to be broken down. Even the human liver can't stand a high alcohol diet and will suffer damage, or develop conditions such as cirrhosis. –Mysid☎ 08:15, 11 November 2006 (UTC)

It brings up the question as to why is alcohol intoxicating? It seems that if alcohol were so debilitating, users of it would be selectively removed from the gene pool. I suspect that spoiled grain and fruit were staples of the early diet and that natural alcohols needed to be processed whence the development (or rather selection) of alcohol dehydrogenase. I don't think it was alcohol that was produced by bacteria in the digestive tract as that bacteria would still exist. Does that bacteria exist? Whose water do you have to drink to get it? --Tbeatty 08:38, 11 November 2006 (UTC)

It seems that if alcohol were so debilitating, users of it would be selectively removed from the gene pool → I'd say that the increased child conception rate among intoxicated humans probably weighs more heavily in natural selection. :) Scientizzle 22:40, 11 November 2006 (UTC)

You can look at nearly every non-inert small organic molecule, and it will be toxic in the quantities people fill themselves with. Most chemicals are poison, really. -- Rwst 11:48, 11 November 2006 (UTC)

Why are you so sure humans have a unique ability to breakdown alcohol? Do you have any evidence for this? I suspect you will find chimpanzees and cats probably have similar abilities as ours. Bear in mind a fair number of Asian people have defects in acetaldehyde dehydrogenase affecting their ability to digest (and therefore consume) alcohol (see Alcohol flush reaction) Nil Einne 14:49, 11 November 2006 (UTC)

The question is really good. Consider methanol as a counterexample. AFAIK it is also naturally produced by bacterial decomposition, however, it is significantly more toxic than ethanol. A glass of 40% methanol will probably kill you, a glass of vodka will probably not (unless you drive, but that's a different story). Anyway, what is the biological significance of ethanol? Does it has a signal function of some sort like Nitric oxide, or is it just "serendipity" that ethanol doesn't kill us straight away, while methanol or, say, acetone do? I do not know. Anyone? --Dementios

Alcohol dehydrogenase also breaks down methanol and ethylene glycol to a certian extent, and you do actually produce very small amounts of acetone when your body is in a fasting state, see Ketone bodies, of course acetone is waste product, and it leaves your body the way most waste products do--71.247.105.54 19:55, 11 November 2006 (UTC)

You're begging the question. What is a large amount is determined by how much the body can handle. Another consideration is that humans have probably drunk alcohol for a very long time. If that is long in evolutionary terms, I don't know (and is probably almost impossible to find out), but making alcohol is very simple and probably happened in many places by mere coincidence (eating food that has gone 'off' because you're hungry). DirkvdM 10:05, 12 November 2006 (UTC)

Our tolerance for EtOH is definitely due to the fact that it is natural decay product of fruits, etc. And a recent article in New Scientist (I think) suggests that animals deliberately choose the more-rotted fruit, apparently exactly for its intoxicating effects. "Barkeep, pass me that really nasty-looking plum over there... Hic!"

Atlant 13:47, 13 November 2006 (UTC)

Hospital Information

Is there a free site where I can find information regarding surgical volumes for medical facilities?

Are you talking globally? Nationwide? For some region? Over what period? Anchoress 07:41, 11 November 2006 (UTC)

What's a "surgical volume?" Tbeatty 08:29, 11 November 2006 (UTC)

At a guess, I would think he mean's how many patients for all kinds of surgery there are (i.e. surgical throughput). However the question is in what area and over what period as anchroess said. Nil Einne 15:25, 11 November 2006 (UTC)

Radial Tunnel Syndrome

I was diagnosed with Radial Tunnel Syndrome and all I was given was anti-inflammatories. I was not given or told to wear a brace or do any type of excercise. My next appointment is in 6 weeks. My two questions are: (1) should I be doing some type of treatment during these 6 weeks, such as wearing a brace. (2) What is the full recovery rate percentage, and if everything goes as planned (whether it's surgery or non-surgical treatment), will I be able to do serious heavy lifting again.

The Reference Desk cannot give medical advice. However, by googling I found e.g. Merck and RSI which suggest avoiding rotating the wrist or bending the arm at the elbow. –Mysid☎ 11:47, 11 November 2006 (UTC)

Ok, skipping question 1 then, is there any statistics concerning full recovery or to what extent you can recover if everything goes as planned as stated in question 2?

The little black hole that could

Suppose we created a microscopic black hole. Ignore Hawking radiation and assume that the black hole's mass is exactly equal to the mass of material that has passed through its event horizon. We are going to place our black hole on the surface and watch it fall through the Earth's gravity well, eating matter as it goes. It will oscillate through the Earth, falling from one side to the other. Assume also that the earth is a rigid, uniformly dense sphere with infinite structural integrity, so it won't collapse in on itself - the only way to remove matter from the earth is to transfer it into the black hole, and that only happens to matter that crosses its event horizon.

Initially, the black hole has insignificant mass and will just pass through the earth. Over time, however, more of the earth's mass will be transferred into the black hole. What I'm actually interested in is, what would be the behaviour of this system under Newtonian mechanics? We have what is basically a point mass falling through a uniformly dense sphere, and the point's mass grows from zero to one in direct proportion with the sphere's mass shrinking from one to zero. How would the two bodies movements change as the black hole grows? Any other interesting thoughts about this idea are welcome. Maelin (Talk | Contribs) 12:55, 11 November 2006 (UTC)

You cant have little black holes, they have to be of such a mass that when the star that created them collapsed, they were crushed by their own gravity, into a singularity, which is my other point, all black holes are the same size, in that they have no size. They are singularitys. Philc _T^E_C^I 14:12, 11 November 2006 (UTC)

Of course, you can have little black holes. Every star size BH will shrink to such a size, due to Hawking radiation. As to the original problem, it boils down to the same problem of a second mass in Earth's orbit if the BH is on an orbit that doesn't pass through the earth. If it passes through, deceleration because of side effects like a mini accretion disk and such will lead to it orbiting the mass centre of the Earth within the Earth, with crushing it finally when it has enough mass. -- Rwst 14:58, 11 November 2006 (UTC)

Three points: Microscopic black holes are theoretically possible - and are believed to have existed in the early Universe. The current thinking on Hawking radiation is that it wouldn't actually cause black holes above a certain size to evaporate (the method by which Hawking radiation is generated means the black hole must absorb matter in direct proportion to the radiation they 'emit' (for want of a better word). The second point: Black holes are a feature of GR; there is no Newtonian treatment of black holes. Thirdly: Black holes do have a size. The event horizon of the black hole marks its boundary and has a radius dependent on the mass of the black hole (known as the Swartzchild radius)

May we assume that the black hole is not rotating, and that – as the Earth in this problem has "infinite structural integrity" – the black hole eats out a hollow track with cross section πr², where r is the Schwarzschild radius of the black hole?  --Lambiam^Talk 19:46, 11 November 2006 (UTC)

Note that, as the black hole feeds, it's event horizon will expand. (Unlike us, however, it won't need to loosen it's belt.) :-) StuRat 20:06, 11 November 2006 (UTC)

In answer to the above: Whilst obviously the black hole has a volume, since even if the entire earth were consumed, the black hole would be 9 mm in diameter. we can pretend it's a point mass as long as we allow matter in the Earth to still be swallowed. I merely raised this to help modelling, if treating it as a tiny sphere is no more difficult, then sure, whatever. Also, never mind that black holes aren't actually properly modelled by Newtonian physics. As long as we aren't within the event horizon we can pretend it is still a normal Newtonian body (I think). Lastly, I'm not sure what the rotation of the black hole would affect, please elaborate? And yes, that's a fair assumption. We can even pretend the black hole has a radius of 9 mm the whole time if it simplifies things, as long as we acknowledge that its mass will grow as it consumes the Earth. Maelin (Talk | Contribs) 11:41, 12 November 2006 (UTC)

You might enjoy the David Brin sci-fi novel Earth; it examines exactly this concept.

Atlant 13:52, 13 November 2006 (UTC)

Hard skin

Is there a name for a lump of hard skin just below the surface. I have one and the doctors (including the orthopedic surgeons) dont know what to call it. --Light current 16:04, 11 November 2006 (UTC)

You'll have to be more specific or else provide a picture. If it's a hard lump, it's important to know whether or not it feels like it is attached to the skin or moves separately from the skin. Dermatologic questions are really hard to answer over the internet. InvictaHOG 18:33, 11 November 2006 (UTC)

It seems attached to the outer surface of the skin and can be moved about =/- 5mm horizontally in relation to the underlying flesh. Its a hard lump A bit like a seg but uner the surface. Surgeon says it might be a cyst but wont know till he cuts it out. If its not serious (ie just hard skin) I may not want to have it cut out as it will leave a scar and prevent certain activites that I use my hand for.--Light current 18:49, 11 November 2006 (UTC)

I think that last part was TMI. Are you sure it's not a swollen gland in the hand? --Tbeatty 21:13, 11 November 2006 (UTC)

I didnt know there were glands in the hands! Unless you mean .... Oh and actually I use my other hand for that ! 8-)

--Light current 21:32, 11 November 2006 (UTC)

Answering these might help: 1) where is it exactly, the skin of the palm is different than the skin on the back of your hand? 2) Is it in an area which experiences constant or frequent friction, vibration, or pressure? 3) does it hurt? 4) what does it look like (red? blotchy" white? &c.)? 5) How long have you had it? 6) Have you ever had anything else like it? 7) Any thing else interesting aboout it or you that might help (does it pulsate?, do you eat a lot of raw pork? &c.) Tuckerekcut 21:33, 11 November 2006 (UTC)

1. Ball of thumb
2. Not excessive
3. A bit
4. white like thick skin
5. 12 months approx
6. No
7. I rest that thumb on the side of the bass whilst playing. I dont eat pork. No pulsations--Light current 21:37, 11 November 2006 (UTC)

--Light current 21:37, 11 November 2006 (UTC)

Sounds like a simple heloma. Does your surgeon know you play a string instrument? Tuckerekcut 22:43, 11 November 2006 (UTC)

Sorry, thought that would link, another term is callus.Tuckerekcut 22:44, 11 November 2006 (UTC)

Yes I told him. But can callouses form under the skin?--Light current 00:28, 12 November 2006 (UTC)

Chicks dig scars! Get it cut off, it'll heal pretty fast and leave you a nifty scar! 192.168.1.1 4:17, 11 November 2006 (PST)

Calluses are sort of like a thickening of the skin, so the swirls of your thumbprint would remain. You can think of it sort of like a blister, but instead of fluid there are more skin cells. One other thing to rule out though: any chance you work in a laboratory, have recently travelled to Bangaladesh, live near Mystic Lake, or work in wet industry? Tuckerekcut 01:00, 12 November 2006 (UTC)

I can rule out all of those. 'Sort of like a blister, but instead of fluid there are more skin cells' describes it perfectly! Whats it called? just a callus?--Light current 01:02, 12 November 2006 (UTC)

Just a callus, heloma in medical parlance, and hyperkeratosis for the generalized condition. Salicylic acid (wart remover strength) is sometimes used for removal, if it's bothersome enough to warrant the effort. Remember, this in no way constitutes medical advice, see a doctor (again) if you feel that you have a medical problem. Tuckerekcut 03:12, 12 November 2006 (UTC)

Funny you say that. Because one doctor said it might be a sort of wart! I dismissed this becuase it doesnt look like a normal wart to me-- but he may have been correct. THanks for the info!--Light current 23:38, 12 November 2006 (UTC)

Sounds like a heloma or a palmar wart. See a dermatologist or plastic surgeon; it's easily dealt with, but some recur -- Samir धर्म 03:58, 14 November 2006 (UTC)

Laypersons

Why do laypersons think they understand many concepts that no physicists claim they understand? This is particularly prevalent with questions concerning black holes and some aspects of quantum mechanics. (This may apply to other sciences)

• Usually bad Cable Scifi/Cop/CSI shows, writters tend to throw around very bad science as technobabel--71.247.105.54 17:08, 11 November 2006 (UTC)

Becuase theyre looking at it from a different point of view untrammelled by the 'facts'?--Light current 17:14, 11 November 2006 (UTC)

Sort of like this whole page :)? --Tbeatty 21:14, 11 November 2006 (UTC)

While the math requires a physicist, the interpretations do not. For example, the fact that certain "particles" follow a wave probability function doesn't immediately tell you what that says about them. The interpretation, however, is that they really aren't in any particular location, but only have a probability of being there. Also, whether they are passing in and out of parallel universes seems to be a matter of interpretation, depending on what one makes of double-slit experiments. StuRat 19:48, 11 November 2006 (UTC)

• Exactly right, when people draw interpretations without actually understanding the underlying concepts, they usually wind up pulling interpetations out of their asymptotes. But popular mistakes usually take on a life of their own, and before you know it they become "common knowledge" For instance, the difference between a 'Parallel universe' and a Parallel universe, or 'Zero-point energy' and Zero-point energy.--71.247.105.54 20:10, 11 November 2006 (UTC)

Hmmm Shouldnt those pages be 'dab'ed?--Light current 20:41, 11 November 2006 (UTC)

Zero-point_energy#See_also and Parallel universe, one's a see also, the other is already disambiguated--71.247.105.54 20:44, 11 November 2006 (UTC)

While the math requires a physicist, the interpretations do not. This is exactly the point. The maths strongly resists interpretation into non-mathematical language. Added to that, the 'interpretations' are all drawn by physicists who already understand the maths and can very rarely be appreciated by people who don't understand the underlying maths. This is largely what leads to laypeople's mis-understanding of concepts.

• This problem is not restricted to "laypersons". For example, see Quantum mind. There have been famous physicists who fell into the trap of imagining that their understanding of physics can explain more than it actually can explain. Some of this started from a long tradition in which mathematicians imagined that everything is numbers and that we should be able to explain everything just by thinking and finding the right equations. Some people who fall in love with mathematical physics seem to play a game of pretending that they can explain everything. Physics has a strong tradition of allowing theory to get ahead of experimental confirmation. When this leads to a new discovery that can be matched up with observation and evidence then the Nobel prizes are handed out. When there is no correspondence between observable reality and a neat idea in mathematical physics, some people prefer to abandon reality. You can always imagine that the silly experimentalists just have not yet figured out how to confirm the "truth" of your pet theory. --JWSchmidt 23:21, 11 November 2006 (UTC)

Determining molecular structure

How do you determine the structure of a molecule? Jack Daw 17:36, 11 November 2006 (UTC)

Look here -- Dementios.

NMR, mass spec, IR, just to name a few, depends on what the molecule is, and in what state your sample is in--71.247.105.54 19:40, 11 November 2006 (UTC)

Also, X-ray crystallography. And more and more often, computer modelling.

Atlant 13:55, 13 November 2006 (UTC)

Why does nature likes so much to produce things in pairs? (two ears, two eyes, two lungs, two legs, four legs...

So why is it? Are intelligent creationists right?Mr.K. 20:13, 11 November 2006 (UTC)

• See Bilateral Symmetry, Bilateria, and Developmental biology, also Embryology while you're at it --71.247.105.54 20:17, 11 November 2006 (UTC)

Symmetry and redundancy. Anchoress 20:19, 11 November 2006 (UTC)

Symmetry. And Yould have difficulty walking with only one leg.--Light current 20:34, 11 November 2006 (UTC)

If humans had only one foot they would probably have some other mechanism of moving. ("Intelligent creationists"? :-) –Mysid☎ 20:53, 11 November 2006 (UTC)

"intelligent creationist": someone who believes on "intelligent creation", also plainly known as creationist. It sounds logical isn't it?Mr.K. 20:56, 11 November 2006 (UTC)

I know, just sounded like an oxymoron. –Mysid☎ 21:44, 11 November 2006 (UTC)

Birds have only one functional ovary 1. The animals they evolved from had two 2. Why would an intelligent designer make them with one functional and one nonfunctional ovary? That doesn't seem that intelligent to me. --Cody.Pope 21:43, 11 November 2006 (UTC)

That's nothing. Much more stupid is the fact that an intelligent designer creates stupid beings.Mr.K. 21:58, 11 November 2006 (UTC)

Maybe because it would take an unacceptable additional level of complexity for DNA to accomplish a bird with two working ovaries. One of the few things that we understand about gene interdependence is that it's complicated. Maybe he couldn't make the model work out so he had to accept a nonworking ovary- after all, you can't make a coherent model of physics but make gravity not apply to airplanes, and unless you want to make a physics model that somehow allows for the detection of airplane shapes and makes gravity not affect them, you're going to have to find some other way of doing it (making due with several tons of dead weight in the form of wings, engines, fuel ,etc). I don't know, that's just what came to mind; often creationist ideas are too quickly bashed with stupid arguments. Come up with a valid argument or don't say anytihng at all. --froth^{T C} 23:00, 11 November 2006 (UTC)

Wait, so your argument is that an omnipotent creator found it too difficult to make a more effective system. That goes against the definition if omnipotence. --Cody.Pope 01:03, 12 November 2006 (UTC)

With planar symmetry, common to most animals, anything on one side of the plane will be duplicated. With radial symmetry, however, any number of copies can exist. Many plants exhibit radial symmetry, and do have odd numbers of petals on flowers, etc., as a result. There are also some animals with radial symmetry, like jellyfish (or, more generally cnidaria). StuRat 21:53, 11 November 2006 (UTC)

And Echinodermata, my favorite radially symmetric folks. –Mysid☎ 22:43, 11 November 2006 (UTC)

• There are only a few simple ways to break the symmetry of a mass of cells in an embryo, such as invagination. It is mechanically easy to convert invaginations of embryos into a "midline" that defines an axis of bilateral symmetry. Multicellular organisms with bilateral symmetry have a selective advantage in many situations, particularly for organisms that must move quickly from place to place in their environment. --JWSchmidt 23:04, 11 November 2006 (UTC)

Critters have a chance (albeit diminished) of surviving the loss of one eye, one ear, etc. That's probably why we aren't up to our elbows in Cyclopses. Clarityfiend 00:57, 12 November 2006 (UTC)

There is a game theoretic explanation for prey species. Suppose that a rabbit had asymmetric leg strength. This would make it more likely to dart left rather than right (say). The rabbit's predators would then evolve to be stronger running left than right (in order to keep up with the rabbit). Then, the rabbit would do better by being stronger on the right. In this simple game the only evolutionary stable state is one where a rabbit (and predator) is equally strong on both sides. --best, kevin [kzollman][talk] 02:36, 12 November 2006 (UTC)

Having two eyes is an advantage because it increases the owner's field of view, and because it provides depth perception. Having too ears makes it easier to locate the source of a sound (this is also depth perception). --Bowlhover 03:22, 12 November 2006 (UTC)

And on the 7th day, the intelligent creator got drunk. Rockpocket 03:11, 12 November 2006 (UTC)

No, that happened on the 8th day. That's why our retinas are installed backwards. --Bowlhover 03:22, 12 November 2006 (UTC)

"And on the 7th day, God looked and saw what he had done, looked around to make sure that nobody else saw, then fled the area, afraid that the more competent gods would catch Him and make him clean up His mess." :-) StuRat 07:24, 12 November 2006 (UTC)

Good one, Stu. Can I add it to my user page? --Bowlhover 22:56, 12 November 2006 (UTC)

Absolutely. StuRat 04:56, 13 November 2006 (UTC)

Another way to look at this is that:

• One is too few (no redundancy, no 360 degree vision, no stereoscopic vision,hearing, etc.)
• Two is sufficient (to give N+1 redundancy for most functions while enabling those fancy technologies)
• Three+ is excessive

So evolution usually tends to stabilise on two somethings.

Atlant 14:00, 13 November 2006 (UTC)

Oxygen used

I asked this before but didn't get what I wanted. How much oxygen does a human use in an hour? How much does a house plant give back? How long could a live human last in a sealed coffin with a houseplant before asphyxiating? Thanks! Reywas92^Talk 22:56, 11 November 2006 (UTC)

Just a note: a houseplant will not give any oxygen without light for photosynthesis, so you would have to make the coffin out of glass. (Just in case you're planning that.) –Mysid☎ 23:03, 11 November 2006 (UTC)

Sure then, make the coffin out of glass. Reywas92^Talk 23:10, 11 November 2006 (UTC)

Why not try it? Then report back (if still alive)--Light current 00:16, 12 November 2006 (UTC)

A houseplant, even under ideal conditions, will only make a tiny portion of the oxygen a person needs (maybe 1/1000th). So, the plant in the coffin will actually make things slightly worse, as the air displaced by the plant would have contained a few minutes worth of oxygen. StuRat 01:41, 12 November 2006 (UTC)

This link says that 22 L of oxygen is produced for every 150 grams of plant matter grown. Assuming a regular houseplant is 450 g, and that it took 2 years to grow to that weight, then it produced 66 L of oxygen in two years. That's about 4 mL of oxygen per hour. Meanwhile, this experiment measured the human body's oxygen consumption at 200 mL per minute, or 12 L per hour.

These figures are very inaccurate, but they should be good for an order-of-magnitude comparison. --Bowlhover 02:27, 12 November 2006 (UTC)

You may also have to account for the volume of plant material grown by the photosynthesis. Perhaps see the Biosphere 2 article?

Atlant 14:03, 13 November 2006 (UTC)

Since algae produces most of the oxygen on earth[2], it might be better suited for your purpose. Especially since water is needed (6H2O + 6CO2 -> C6H12O6+ 6O2) for the photosynthesis process. Maybe a little research on closed systems would help you. LinuxSneaker 14:55, 14 November 2006 (UTC)