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June 15

Buoyancy and pressure

Hi, if I took an object that normally floats to the bottom of a deep ocean at some enormous pressure, then, ignoring the fact that the water might be very slightly compressed and therefore very slightly denser, and assuming the object itself is incompressible, am I right in thinking that the buoyancy of the object would be exactly the same as very near the surface? In other words, pressure alone does not make any difference to buoyancy? 86.160.221.194 (talk) 02:57, 15 June 2012 (UTC)

You are correct, as the buoancy comes from the object's volume displacing that amount of water (providing that no part of the object projects above the water surface). If both the object and the water are incompressible, then the difference in mass between the object and the water that would fit within its volume will always be the same regardless of depth or pressure. Ratbone58.164.224.145 (talk) 03:07, 15 June 2012 (UTC)

"clear" safety glasses

My "clear" safety glasses I bought are not really "clear" in that they are not as clear as glass. Are there any that are actually clear. They are hard to see through you cant see detail well. It also seems light dosent pass well and it seems dark. --Wrk678 (talk) 05:55, 15 June 2012 (UTC)

I remember when I first had to wear safety glasses at work. I was not happy with them either - it is hard to define exactly why, but they didn't seem as clear as I thought they should be. But objective testing, such as reading fine print or looking at leaves on a distant tree showed that in fact they did not affect sharpness. And after wearing them a week or so I got used to them. I think part of the problem is that they don't have any anti-reflective coating like spectacles usually do. At least in Australia, all safety glasses are the same as to quality of vision. In some fields of employment, such as electronics lab work, assembly, and servicing, most employeers will permit wearing only prescription spectacles, provided that the lenses are shatterproof. This is what I wore on the job, with various employers, ranging from electronics servicing, lab work, and light machine shop work - for other work I had to wear a full-face safety mask. In some cases they will also stipulate that side wings are fitted, so that wire offcuts and the like cannot enter your eye from the side. Spectacle shops usually don't stock side wing frames, but they can order them in for you. Presciption spectacles will of course give you the best possible vision, especially if made with low refractive index lens material (not to be confused with the lens power). Check with your employer. If your supervisor is not aware that prescription specs fitted with side wings are ok in your industry, then provide him with evidence. Ratbone121.215.129.221 (talk) 07:01, 15 June 2012 (UTC)

I dont wear prescription glasses

Depending on why you need them, different types of safety glasses may be appropriate:

1) For potential high velocity objects, say if you are working with a chainsaw, you need the best ones.

2) If you only need to protect against dust, then you can get by with soft plastic goggles, which should be easier to see through. (If they get scratched, replace them.) StuRat (talk) 16:25, 15 June 2012 (UTC)

Are there different levels of opaqueness or something? A couple years ago I bought some safety glasses which were the hard plastic type and they were much more clear to see-through than the ones I have now. It also seems that there is a big problem with the light coming through the glasses it seems like they restrict light I don't understand why that would be the case if they are actually clear.--Wrk678 (talk) 00:35, 16 June 2012 (UTC)

Did you get, by mistake or some other reason, lenses that were tinted for some special application? Ratbone120.145.193.114 (talk) 01:32, 16 June 2012 (UTC)

Tempered glass may have different optical properties from normal glass, due to doping the glass with other chemicals. StuRat (talk) 03:29, 16 June 2012 (UTC)

Tempered glass is essentially stress-relieved glass, as the Wiki article says, achieved by special thermal processing. As such it should have better optical properties. Stress results in inconsistent refractive index and increased attenuation. Wickwack124.178.50.166 (talk) 06:01, 16 June 2012 (UTC)

There's also a chemical process where they replace sodium with potassium in the glass. How does that affect the optical properties ? StuRat (talk) 06:55, 16 June 2012 (UTC)

Ontogeny recapitulates phylogeny

I'm not a biologist but I can't believe that ontogeny is no longer used as a valuable though not infallible source of clues for things to check on when investigating phylogeny, much as some modern highways parallel older roads, with some shortcuts and changes. The article says the theory is defunct. I think it can't be defunct, except if it's taken to be infallible. 1)Am I wrong, is "Ont recaps phyl" never absolutely never of any use to real scientists? or: 2)Is the article's claim just the latest oversimplification put into introductory textbooks and transferred to wikipedia?Or: 3)Is it also an effort by creationists to undercut evolution status as a well established theory?--Rich Peterson76.218.104.120 (talk) 09:25, 15 June 2012 (UTC)

I think you misunderstand the distinction between comparative embryology and ont-recaps-phyl. Ontogeny itself is absolutely still studied, and gives valid if imperfect predictions of the evolutionary relationships of different organisms. You can compare the two as so: Comparative embryology would predict that in looking at the embryos of a mouse, an ape, a human, a frog, and a fish, you can construct a phylogeny of the organisms based on ontogenic similarities. Recapitulation theory, on the other hand, would predict that in looking at the embryo of a human, it would actually resemble at various times a fish, an amphibian, a rodent, an ape, and then finally a human. The confusion may have been caused by subtle wording issues. Ontogeny can construct a phylogeny. It does not recapitulate it (physically manifest as it). Someguy1221 (talk) 09:45, 15 June 2012 (UTC)

i'm sure, as i did suspect, and indicated above, that what you say is true. But i'm talking about what the current wikipedia article says.(thanks for pointing out the real title is recapitulation theory) Also, is it really standard in current scientific literature to refer to the "infallible" version as recapitulation theory, rather than something like "strict form of ontogeny recapitulates phylogeny"?--It seems like a hijacking of terminology, another reason why i suspect creationists are partly behind the article.--Richard Peterson76.218.104.120 (talk) 10:11, 15 June 2012 (UTC)

The OP is already posting [1] at the article Talk page[2] which is shared by openly declared creationist(s) and others. There is no need to "suspect creationists" or to divert a discussion of the article's subject to this desk. DriveByWire (talk) 11:05, 15 June 2012 (UTC)

I like Haeckel, and I think the idea, as a very general and quite fallible rule of thumb, is far from useless. It was taught in classrooms long after evolution was accepted as fact. It can be seen as related to the notion of heterochrony as a method of evolution. For example, consider tunicates in comparison to vertebrates and other chordates. Probably tunicates are not basal to the phylum - rather, they have added a stage at the end of their development during their evolution, transforming from a vertebrate-like creature with a notochord to a sessile pumping sack. But it is also possible that they are in fact basal, and the rest of us have lost the sessile stage, like axolotls. Now, Haeckel's rule of thumb would argue in favor of the first version, which is now finding favor from other data; that's the sure sign of a good rule of thumb. But we can't rule out the second idea either. (It might yield interesting biomarkers for, say, the tenured professor) Wnt (talk) 14:36, 15 June 2012 (UTC)

{{{Thanks to all who have responded so far. DriveByWire,after doing an initial edit on the article recently, i decided i wanted clarification on the status of ontogeny vs. pjylogeny. Ijust wanted to learn something the article wasn't supplying, so it was appropriate for me to ask it here. My suspicion that the article was misleading was confirmed by the reply of the obviously knowleadgable Someeguy1221 (and later by the obviously knowledgeable User:Wnt. A few minutes after replying to Someguy1221 I decided the article badly needs someone knowledgeable to work on it, and yes I did suspect creationists had been working on it. So I put up an expert needed tag. But what do you mean I don't I "need" to suspect that about creationists? Do you mean I shouldn't say so, or that it's obviously true, or NOT true, or what? I'm not saying you're wrong, I just want to know what you mean. Best wishes, Richard L. Peterson76.218.104.120 (talk) 23:17, 15 June 2012 (UTC)

Creationists are as welcome as all other editors to work consensually on Wikipedia articles, but do you disagree Richard? I mean that when something is true, you know it is true, you are free to say it is true, but you no more need to say you suspect it to be so than anyone needs to say they suspect that their feet are partly behind an effort to make them walk. When you say what you suspect, consider the etymology of such a tendentious word: suspicion late 13c., from Anglo-Fr. suspecioun, from O.Fr. suspeçun, sospeçon "mistrust, suspicion" (Fr. soupçon), from L. suspectionem (nom. suspectio) "mistrust, suspicion, fear, awe." DriveByWire (talk) 16:43, 16 June 2012 (UTC)

But i didn't know it76.218.104.120 (talk) 02:37, 17 June 2012 (UTC)

Clarification: I suspected 2 things. One was that a less strict form of recapitulation theory was far from defunct. This was confirmed by a couple responders above. I also, as I was writing my first post above, started guessing about the current article's tone and began to suspect that a creationist agenda was controlling it.But I didn't know that.... Of course, all are welcome to contribute, but it is preferred that the overriding agendas for any contribution are fairness, balance and verifiability.76.218.104.120 (talk) 06:46, 17 June 2012 (UTC)

You didn't know? If you had bothered to read the Talk page for the article you would have plainly seen an editor declaring "I'd better state first that I am a creationist." You could have saved yourself some time by doing so. The Wikipedia guidelines on fringe theories, but not anyone's imagined "agenda to control", apply to the article. It seems silly to politicise the ORP slogan as a stance in an evolution vs. creation debate because the features seen (or not seen) in embryo development can be accomodated by either viewpoint i.e. the subject is not pivotal in the debate. In my opinion no credible debate even exists, but that does not justify a witchhunt for holders of a minority theory that you suspect are infiltrating Wikipedia articles. It does not look like this desk can help you with any futher references beyond the article you already cited. DriveByWire (talk) 00:59, 18 June 2012 (UTC)

So Rich imagined creationists controlling the agenda and DriveByWire imagined Rich going on a witchhunt? Can't we all just put our imaginations down and get along? 203.27.72.5 (talk) 02:30, 18 June 2012 (UTC)

A theory about alternate timelines

Is there a theory which states that every time a decision is made, one or more parallel timelines split? I'm aware that there is a theory where changing the past results in an alternate universe, but what about alternate timelines? Narutolovehinata5 ^tccsdnew 14:03, 15 June 2012 (UTC)

Many-worlds interpretation Wnt (talk) 14:36, 15 June 2012 (UTC)

Thanks. Narutolovehinata5 ^tccsdnew 14:43, 15 June 2012 (UTC)

Resolved

Many-worlds interpretation isn't about humans making decisions, its about quantum effects that can have multiple, unpredictable outcomes. thx1138 (talk) 16:21, 15 June 2012 (UTC)

These are not unrelated. There are only two possibilities that fit within existing physical theory:

1. Human decision-making is a deterministic process; there is no free will
2. Human decision-making is affected by quantum indeterminacy

If option 2 is true, then the many-worlds interpretation says that every decision you could have made actually occurs, in an alternate "world". This is less fantastic than it may seem, and should not be any more surprising than any other quantum paradox. (Schrödinger's cat, for example)--Srleffler (talk) 17:37, 15 June 2012 (UTC)

(edit conflict) Well, only in the sense that any possiblity of anything at all exists in an "alternate world". At an given instant, an atom may decay or it may not, a virtual pair may form spontaneously or it may not, etc. etc. Every possible, but not yet occured, physical change from the way the universe is this will happen in one of a near infinite number of universes which will be created in the next instant, and so on and so on. Since humans exist and are made of matter, they're part of that too. --Jayron32 17:58, 15 June 2012 (UTC)

That's a rather common but fallacious dichotomy. Volition is the faculty that allows higher animals to act when outside factors do not determine their choice. For example, you can either stay in bed or get out, exit on the left or the right--whereas plants merely grow toward the sun given the proper external stimulus. That is volition, or will, and it is why Buridan's Ass doesn't starve. The freedom of the will is not the freedom of the body from physical reality or the freedom of the self from the body, but the moral freedom of the volition from the coercion of others. If a criminal ties you to the bed you are not staying in the room of your own free will. You are your body, so it is absurd to argue that it wasn't you who chose to do something, but your body. (That's setting aside organic disorders that interfere with the proper functioning of your volition.) μηδείς (talk) 17:54, 15 June 2012 (UTC)

The sticking point is the "you are your body" part of it. In my opinion there is no possible satisfactory materialist account of free will. I am a hardcore incompatibilist on this point. --Trovatore (talk) 00:40, 16 June 2012 (UTC)

Well sure, that's like saying there's no satisfactory quantum physical explanation of sexual selection, or no chemical explanation of the electoral college. Of course there isn't. They are on different levels of explanation. The problem is the bizarre insistence on materialism as explaining anything but chemistry. What is the molecular weight of a shadow? What is the electrical valence of truth? These questions reveal the essential fallacy of category errors.

No, that's not my point at all. There is no acceptable account of free will that does not reject materialism, that does not say materialism is false. --Trovatore (talk) 01:00, 16 June 2012 (UTC)

I don't quite understand your statement. I hold that there are such things as true statements and good actions, and I don't hold that the truth of a statement or the morality of an action can meaningfully be reduced to chemical equations. I will assume you both understand and agree with that? μηδείς (talk) 01:12, 16 June 2012 (UTC)

I am saying that if there is nothing beyond the physical universe, then there is no morality or meaning, and nothing matters at all. Fortunately, there is something beyond the physical universe. --Trovatore (talk) 01:27, 16 June 2012 (UTC)

The laws of physics allow unversal computing devices to exist which can thus run any type of algorithm that can implement whatever (inexact) moral laws you can imagine. Count Iblis (talk) 02:28, 16 June 2012 (UTC)

But if there is no one inside to be aware of them, who cares? --Trovatore (talk) 02:33, 16 June 2012 (UTC)

That depends on whether your choices really were the result of free will, or whether or not you merely have the delusion of free will; that is every action you take was predetermined, but your mind makes you think you had some control over it. The trick is deciding how to tell the difference. Which is not to say that I agree or disagree with you, but the difference between believing that you could have made a different choice in any action you take, and actually haing had the choice, is an interesting philosophical problem. --Jayron32 17:58, 15 June 2012 (UTC)

Mηδείς, the dichotomy is not at all fallacious in the context of the question we are discussing. Ignore all the philosophical questions about freedom of will, volition, etc. Assume decision-making is a purely physical process (i.e. no immaterial soul). There are only two possibilities, which I enumerated. One is that the process is purely deterministic, in the sense used in physics. In that case, there is no splitting of timelines. It's not clear that this is the case, however: we know that our universe is not deterministic in this sense: quantum mechanics demonstrates that there is true, irreducible randomness in the universe, and that things can exist in more than one state at a time. Usually these effects are observable only on microscopic scales, but they are not always limited to such small scales. It is possible that human thought is affected by quantum randomness, that when we make at least some decisions, quantum uncertainty could affect which choice is made. If so, then the many worlds interpretation applies—each choice that was affected by quantum uncertainty corresponds to a splitting of timelines.--Srleffler (talk) 03:42, 16 June 2012 (UTC)

It's interesting that John Wyndham wrote ""every instant an atom of time splits" in The Seeds of Time before 1956 (I remember reading it before I'd ever heard of quantum mechanics), and the "Many Worlds" interpretation was published in 1957, but I assume Wyndham had read some earlier papers. The concept is a fairly obvious one, I suppose, and goes back thousands of years as a philosophical concept. Dbfirs 18:23, 15 June 2012 (UTC)

I don't think you understand my point exactly, Jayron. There is no such thing as a you that is separate from your body or the physical things which comprise it. (That's a notion left over from religion. What your body does is what your body does.) One of the faculties you and other higher animals have is volition--the ability to choose between different perceived paths of action. We're not talking about its freedom yet, just that volition exists. Plants don't have that faculty, nor do rocks, nor do atoms. It's a higher level emergent property of certain living beings. Now, of course it depends on your physical make up. Whether you get out of or stay in bed and on what side depends on processes that percolate in your brain. They are physical and at certain levels they are guided by certain natural laws. Eventually you-which means your body-which means your cells--which means the atoms that make it up--will come to a decision. Whether the rules that govern the motions of those atoms are in principle newtonianly determined or random doesn't matter to the higher level fact that your body can come to decisions. What makes those decisions free is not a physical, but a moral distinction. Was it your body that chose to stay in bed, in which case you are acting of your will freely, our did you burn to death because you were tied to the bed, in which case it was not of your--your body's--free will. To say that you are not free because you are your body--which is what determinists do--is a category mistake. It's almost like saying you can't pilot an airplane because aluminum is heavier than air, just on a more subtle level. Free will is a perfectly valid and necessary concept in a moral, not a mechanical context. μηδείς (talk) 18:37, 15 June 2012 (UTC)

Sorry, the Reference desk is not meant for philosophical discussions. It is not a forum. --Martynas Patasius (talk) 19:41, 15 June 2012 (UTC)

In some recent experiments involving functional MRI it was demonstrated that given some arbitrary choice you can make, one can already tell by looking at the MRI what you are going to choose about ten seconds before you say that you've made up your mind. Then, if you assume some many words scenario (the MWI of QM or the infinite number of regions similar to our observable universe as predicted by inflation theory), and you assume free will, then it becomes even weirder. Because then the moment you make up your mind, you locate yourself in that sector of the multiverse where the people observing your brain have already seen what you have decided. Count Iblis (talk) 21:13, 15 June 2012 (UTC)

I have read of such studies and I don't think the timelag is quite ten seconds. I could ask you to spout a string of random numbers and there would not be a 10 second delay before you started doing so. The fact that we are not aware of what we have chosen or said until after we have chosen or said it is not particularly problematic. If we had to deliberate in conscious words about what we were going to say before we said something we would never get started because we would have to deliberate which words to use in our deliberations, and so on, leading to infinite regress. How any of this fits in with so-called multiple universe theory, which cannot even be coherently formulated, let alone tested is beyond me. μηδείς (talk) 21:32, 15 June 2012 (UTC)

Interesting question. Could you tell what random numbers a person is going to spout before you let him know you want him to do so?

I am not sure, however, whether "you" can't be separated from the physical actions of the atoms in some way. Is there a way to say, that many different rearrangements of the atoms have absolutely zero subjective effect, and others matter? Is there some way to present consciousness as some kind of digital data in an algorithm? Just as a 1 or a 0 in computing can be independent of the minor thermal fluctuations of the chip they're coded in, and when those fluctuations foul up the value, that's not a normal computing operation, but a deviation from the 'intended' operation of the software. Do people perceive the world as the actual atoms, or as that discrete digital data? Wnt (talk) 22:24, 15 June 2012 (UTC)

If I understand your question correctly, you might want to look at supervenience. That is the concept that an emergent state might not specifically depend on a uniques set of lower circumstances, but that unless the underlying circumstances differ there can be no difference in the emergent states. For example, something's being evil might not necessarily depend on any one specific chemical physical states of afiars, but that if two circumstances are fully and exactly the same physically one cannot be evil while the other is good. μηδείς (talk) 23:00, 15 June 2012 (UTC)

That article seems like it must be talking about something else. I'm not suggesting a situation where a "lone ammonia molecule" would make a difference. What I mean is that if our subjective mental experience is some kind of "software", then small variations in the "hardware" may not matter. A simple program written in assembly language doesn't "see" the difference of whether the clock chip is running at a different speed, or whether it's being emulated as a program on some more complex system. The program only sees the parameters that matter to it, and produces its conclusions the same way in every circumstance. Wnt (talk) 03:46, 16 June 2012 (UTC)

I understand your point. Things whose natures are primarily functional can, as long as they are arranged in the proper form, differ in substance. Hylomorphism]] A drinking cup can be made of glass or plastic. It's still a Beethoven symphony whether the cellist is a man or a woman, she wears slacks or a dress, she sits to the right or the left of the wind section. That points out the problem with reductive materialism. Complex forms have to be executed in some substance, but it is the form that is essential.

Let's say I want to remind my self to schedule a doctor's appointment tomorrow. I might write myself a note. I might tie a string around my finger. I might write "Dr." on the back of my left hand in magic marker or sepia or nail polish. I might turn the bottle for my morningtime medicine upside down. There are an infinite number of arbitrary signs I can set for myself. What physically would be determining me to call the doctor in the morning? Sure, my brain and all these other things are made of atoms. But what about the velocity, mass, temperature, molecular structure or so on of these items would explain or "determine" me to call the doctor?

If I don't leave any sign for myself (including maybe internally as a short term memory) I won't call the doctor. But you can't reduce my calling the doctor to whether the string was cotton or wool. Nevertheless you have to admit that had there been no change in my environment I would not have been reminded to call the doctor. This is supervenience, when there cannot be a difference in a set of affairs of one type if there is not a difference in a set of affairs of another type. It is a way of preserving causation without falling into reductive determinism. In morality there cannot be a difference in guilt if there is no difference in intention, action ad result. There cannot be a difference in flavor unless there is a difference in ingredients, preparation and presentation. Note that the relation is not necessarily reversible. A change in preparation (shaken, not stirred) may have no effect on flavor. A change in action (I stabbed him with my right hand, not my left) may have no effect on guilt.

For a much better presentation of the matter by Rutger's Brian McLaughlin, see http://plato.stanford.edu/entries/supervenience/ μηδείς (talk) 16:59, 16 June 2012 (UTC)

Brownian motion of water molecule

When water is in its liquid phase, do its molecules diffuse around in Brownian motion or do they stay more or less in the same place? 65.92.7.168 (talk) 14:24, 15 June 2012 (UTC)

In still water they do both, though Brownian motion usually means the observable movement of particles much larger than one molecule. DriveByWire (talk) 14:32, 15 June 2012 (UTC)

It can't be both - the molecules must be either moving or not moving. The answer to the OP's question is Yes - the molecules do so move. However DriveByWire is correct in stating that term Brownian refers to observable particles suspended in the fluid. The correct term for the movement of molecules driven by thermal energy is random thermal motion, sometimes refered to as random molecular mobility, or just molecular mobility. Still water is only still in so far as convection currents and currents due to external forces are not present. Diffusion (the tendency for a molecular species in solution to even out its concentration) is another thing again, driven by random thermal motion. Ratbone120.145.14.192 (talk) 15:16, 15 June 2012 (UTC)

Perfect, thank you. 65.92.7.168 (talk) 01:20, 16 June 2012 (UTC)

I recommend that you read Diffusion. Plasmic Physics (talk) 02:04, 16 June 2012 (UTC)

Sidewalks that generate energy with our stepping?

Do we have an article about such sidewalks? Also, where are the prototypes already being tested?

Moreover, how far away is it from being practically installed in every major city? (For example, how much does an energy-generating sidewalk cost as opposed to an ordinary sidewalk, per average-sidewalk-sized tile?) Thanks. --70.179.170.114 (talk) 18:03, 15 June 2012 (UTC)

Stepping Razor Lyrics mp3 Bus stop (talk) 18:12, 15 June 2012 (UTC)

Look at the use of piezoelectric devices in the Energy harvesting#Piezoelectric energy harvesting article. (what does lyrics has to do with this at all??) Electron9 (talk) 18:29, 15 June 2012 (UTC)

(edit conflict)They are "hard work" to walk on (try walking in soft sand), so people would avoid them if they were designed to generate a large amount of energy, and if they are designed to be easy to walk on then they don't generate much energy. There are much better ways to get "free energy", so my personal opinion is that they will always remain an inefficient novelty. The Tokyo ticket gate system seems to generate a tenth of a watt! Dbfirs 18:34, 15 June 2012 (UTC)

The pesky rule of conservation of energy. The first physical law breaker criminal has not yet shown up ;-) Electron9 (talk) 18:38, 15 June 2012 (UTC)

Piano stairs are an entertaining variation on this idea. HiLo48 (talk) 07:51, 16 June 2012 (UTC)

That's a delightful idea HiLo48, but unsuited for areas with heavy pedestrian traffic. The viability of any scheme for extracting energy from human muscle activity depends on how much people enjoy the activity. Physical activity that we don't enjoy is called "work". An example to avoid is the fate of a Galley slave, unless you happen to enjoy being encourged by a whip. Another is the erstwhile prison Treadmill that had no purpose other than punishing its victim by wasting (as heat, see Mechanical equivalent of heat)) his effort, a situation that Oscar Wilde would profoundly lament in 1897. So-called energy-generating sidewalks would actually be energy-extracting devices, likely to be perceived as treadmills, and would need an extraordinary infrastructure (overseers with electric batons for encouraging pedestrians to step faster?). However during the 1973 oil crisis and resulting panicky search for alternatives an idea arose that human sexual activity could be tapped as a renewable source of energy. A scientific calculation from objective data on average copulation frequency and duration, typical genital dimensions, viscous drag and thrusting force suggested that significant power might be collected this way and volunteers for experiments in doing so would not be hard to find. DriveByWire (talk) 16:09, 16 June 2012 (UTC)

Microbiological terms

hello,

I am currently translating a German article, but I have troubles to translate the following terms:

• Kinetozysten (kinetocystae maybe?)
• Extrusom

Regards.--GoP_T^C_N 18:43, 15 June 2012 (UTC)

kinetocysts and extrusome. ---Sluzzelin talk 20:04, 15 June 2012 (UTC)

Thanks.--GoP_T^C_N 08:50, 16 June 2012 (UTC)

Human facial hair growth stimulation

Is there any reliable way to stimulate the growth of facial hair on humans?--201.244.29.54 (talk) 19:38, 15 June 2012 (UTC)

Some heart medicine does this. Electron9 (talk) 19:39, 15 June 2012 (UTC)

Testosterone should work, although how effective it is would depend on the body's prior natural level. SkyMachine ⁽⁺⁺⁾ 20:51, 15 June 2012 (UTC)

For some reason shaving seems to have this effect. It seems to come back faster and thicker each time. StuRat (talk) 02:32, 16 June 2012 (UTC)

Shaving increases hair growth is a popular misconception. manya (talk) 07:11, 16 June 2012 (UTC)

This and other hairgrowth-related myths on Snopes. --NorwegianBlue ^talk 08:35, 16 June 2012 (UTC)

They seem to have some questionable logic there. For example, they say that if it worked, those going bald would try it. Well, obviously it would only work on those capable of growing hair, just like cloud seeding to produce rain isn't going to work when the air is dry and cloudless. They also state that cutting the end of a dead piece of hair can't possibly affect the follicle, but the intact hair must cause stresses on the follicle, and it's not unreasonable to suspect that the follicle is able to use this info to alter the growth patterns, just as muscle growth varies with stresses on the muscle. StuRat (talk) 19:09, 16 June 2012 (UTC)

Hairdressers have told me that they were taught during their classroom training that hair growth is not affected by cutting - but I've never really believed it. But it would be hard to prove, as hair growth is affected by climate, hormones, what you eat, lots of things. Even though I am a male past retirement age, I let my hair grow to shoulder length. I used to need to get it cut more often, but now I get it cut short once at the start of summer and once at the end of summer. So, my hair grows faster during summer. It seems to me that if you keep your hair short, your scalp will be cool. If you let your hair grow long, it will insulate your scalp and it will be warmer (it sure feels cool when I get it cut) and a warmer scalp can presumbly grow hair faster.

The snopes article is not referenced and thus thus is not a scientific reference. I'm very suspicious about their claim that hats make no difference. My father's generation wore hats everywhere - it was the fashion then. Many men went bald from their 30's onwards - my father was just about totally bald at 40. I am decades past 40 now and I only have some temple thinning. Like all of my generation, I've never worn a hat, and most of us have reasonable hair. But we have better food too and better general health. However, at least here in Australia, men now in their 30's have been taught at school that they MUST wear a hat outside to avoid skin cancer. And I see that some of them are going bald. So, the moral in the story about encouraging facial hair? Keep your chin warm without a cover, somehow! Wickwack124.178.37.221 (talk) 14:25, 16 June 2012 (UTC)

Um, the snopes article is very referenced. Scroll to the bottom. It's certainly more scientific than your sample set of two (you and your father). I'm 26 and I can tell you I'm well on my way to joining the "bald at 40" crowd". There's probably a good reason why there aren't as many balding men as there used to be, and the idea that it's "hats" is absurd. -RunningOnBrains^(talk) 16:34, 16 June 2012 (UTC)

Those references are mostly just newspaper accounts, likely even more opinions. I'd like to see some scientific studies with thousands of people in them, please. StuRat (talk) 19:14, 16 June 2012 (UTC)

Exactly. Worthless. Wickwack58.170.165.180 (talk) 03:16, 17 June 2012 (UTC)

Is anyone so unlucky as to not get decent beard till 25 and start balding at 24? Sagittarian Milky Way (talk) 18:56, 16 June 2012 (UTC)

To look at me now, you'd think I was born with a beard. But I didn't manage to grow it properly till I was almost 30. All my previous attempts were pathetic failures. By the time I was finally successful, my vision and hearing had started to show signs of wear. There was no balding, though, not at that stage. That came later. -- ♬ Jack of Oz ♬ ^{[your turn]} 12:40, 17 June 2012 (UTC)

Couldn't at least the hearing be because of too much loud music? And I thought 40 was when vision declines. Maybe you're actually farsighted but didn't notice till the lens couldn't accomodate anymore? Sagittarian Milky Way (talk) 17:59, 18 June 2012 (UTC)

Some people researched this long back. manya (talk) 07:31, 19 June 2012 (UTC)

Looks like a good study, except that a data set from only 5 test subjects isn't enough. StuRat (talk) 07:49, 19 June 2012 (UTC)

June 16

Canadian geese

I remember reading somewhere that shooting Canadian geese was illegal for some reason, but this page seems to indicate that it is not illegal. Can anyone clarify this? I'm in the usa.

http://www.dnr.state.mn.us/hunting/goose/tips.html

--Wrk678 (talk) 00:38, 16 June 2012 (UTC)

Depends on your state's laws. 00:45, 16 June 2012 (UTC)

It is also likely to be true that there will be times of the year when such hunting is not permitted, wherever you are. Bielle (talk) 00:52, 16 June 2012 (UTC)

The Migratory Bird Treaty Act of 1918 might apply. StuRat (talk) 02:38, 16 June 2012 (UTC)

Yes, that U.S. federal law is often claimed to apply to Canada Geese. Whether or not a given goose has migrated is a different question. More and more of them don't migrate these days, due to easy overwintering at golf courses, etc. The OP may be interested in this summary of some of the issues [3]. SemanticMantis (talk) 03:13, 16 June 2012 (UTC)

Branta canadensis is listed there, but the bird is residential in many areas. μηδείς (talk) 03:12, 16 June 2012 (UTC)

Their non-residency is why they are properly called Canada Geese. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:07, 16 June 2012 (UTC)

It is a legally hunted bird - If you have a state license, a federal stamp, are hunting in season, in an appropriate area, within your daily and season bag limits, with the legally allowed weapon, and the legally allowed ammunition, the legally allowed amount of ammunition in your gun, with the legally allowed hunting aids, and the legally allowed clothing, blinds, legally allowed movement (and lack thereof), legally allowed bird calls, etc. Many ways to fall afoul of the laws and regulations. Rmhermen (talk) 14:02, 16 June 2012 (UTC)

Why haven't I heard right-wingers complain about so much "government interference in their hunting" for some reason? They complain so much about having to register their gun and get their background checked when buying a gun and wait a waiting period for their gun and having to get a permit to own a gun and not being allowed to buy semiautomatic versions of guns that have too many military features and not being able to sell their guns to anyone that shows up at a gun show without checking their background and not being allowed to buy over one gun a month (or similiar frequency). People in the US that are right wing enough seem to complain about everything, especially anything the government does. Sagittarian Milky Way (talk) 19:43, 16 June 2012 (UTC)

"I have to wait 3 days just to get a gun ? But what if I'm not angry any more by then ?" - Homer Simpson StuRat (talk) 19:47, 16 June 2012 (UTC)

"Why haven't I heard right-wingers complain about so much "government interference in their hunting"" Because you haven't been listening? 203.27.72.5 (talk) 20:33, 16 June 2012 (UTC)

People can't hunt around here. Too many people and not enough animals. McCain got like 10% in the region. I don't watch Fox News. So if it's not in the national news I won't know about it. Sagittarian Milky Way (talk) 21:26, 16 June 2012 (UTC)

Maybe they realize that they will kill each other off without hunting safety regulations, like Cheney almost did. :-) StuRat (talk) 20:52, 16 June 2012 (UTC)

And seriously, if they let people shoot as much as they want there won't be enough animals for everybody. See the passenger pigeon. Sagittarian Milky Way (talk) 21:26, 16 June 2012 (UTC)

Are plastic bag bans worth it?

I've asked a similar question about two or three times already, but it always went out of topic. Now, I'll get straight to the point. From an economic or environmental perspective, is a plastic bag ban worth it? I'm not asking for opinions, merely facts, studies or just logic. Of course from an environmental perspective, at least in the short-term it will be beneficial, but will the economic, environmental and practical cons, such as cutting more trees, the use of more paper and chemicals etc. eventually outweigh the benefits? Will it be effective, and will it be worth it? I read somewhere that in a landfill, paper takes just as long to decompose as plastic, can't remember why though (I think I read it at Listverse). Does this mean that a plastic bag ban is not worth it? I also read that plastic bags wouldn't cause floods if they were more properly disposed and people were more disciplined with their use. Does this mean that a plastic bag ban is not even necessary? Narutolovehinata5 ^tccsdnew 01:11, 16 June 2012 (UTC)

From the POV of visual litter, plastic bags are far worse, in that they can blow around till they get stuck in a fence, while paper bags tend to get wet and soggy and stay on the ground. StuRat (talk) 02:35, 16 June 2012 (UTC)

What do you mean by a ban being "worth" something? I am a hardcore libertarian free-marketeer, but I favor bans on the free distribution of plastic bags for the same reason I favor a ban on the free distribution of firearms. See attractive nuisance and pollution. μηδείς (talk) 03:08, 16 June 2012 (UTC)

What I mean is, if in the long run, a total ban on plastic bags can lead to a better society, or will the problems surrounding such a ban outweigh whatever benefits that are gained? Narutolovehinata5 ^tccsdnew 03:11, 16 June 2012 (UTC)

You say you're "not asking for opinions, merely facts, studies or just logic". If the facts bear out that for every plastic bag not used, one less tree dies, whether it's worth it or not depends on your opinion of the relative values of trees and human convenience. The environmentalist says "yeah, trees are way better than plastic bags" and the Thatcherite says "who cares about trees? I've got to get my groceries home". This question is at it's heart not scientific. The answers will always be tainted by opinion and subjective judgements.203.27.72.5 (talk) 07:42, 16 June 2012 (UTC)

That's really asking for a political opinion then, since free market supporters like myself are, at worst, going to argue that as long as the users and distributers of such bags are held fully responsible for their removal and recycling there is no justification for such a ban. See opportunity cost. μηδείς (talk) 03:18, 16 June 2012 (UTC)

The idea is not to replace plastic with paper, except in small matters, but to replace plastic with re-usable. Some reusable bags are plastic, of course, but they are more durable and meant to last through many shopping expeditions. Until recently, if you went shopping anywhere in Europe, you had better have brought your own string bag or similar. I believe that is still true in small tons or in small stores even in big towns. (I once carried home a half kilo of cherries in my pockets from a store in Mijas Pueblo. Messy.) So, based on this change of habit in North America, it would seem logical that both long-term and short-term savings will be achieved. Bielle (talk) 04:11, 16 June 2012 (UTC)

'Paper bags have been the traditional shopping bag of choice in the US, but while these biodegrade in landfill, the UK Environment Agency study points out that they have a higher carbon footprint than standard plastic carrier bags.

It also says the available evidence suggests paper bags are not generally reused, either as bin liners - a purpose for which they are not well suited - or for other purposes.

Mr Duboise of the Plastic Bag Ban Report website says pressure from the "powerful wood pulp industry" is one reason paper bags are used in the US.

Over the years, supermarkets drifted towards plastic bags, he says. But, he adds: "A lot of supermarkets are going back to paper bags even though the environmental people say it's just as bad as plastic."'

This and much more at BBC News. --Demiurge1000 (talk) 04:31, 16 June 2012 (UTC)

Paper bags don't need to be used as trash can liners, since they can collect trash in a stand-alone manner (both figuratively and literally). StuRat (talk) 04:46, 16 June 2012 (UTC)

"Mr Duboise of the Plastic Bag Ban Report website says pressure from the "powerful wood pulp industry" is one reason paper bags are used in the US."--Is there anything possibly more POV than such a statement? μηδείς (talk) 04:57, 16 June 2012 (UTC)

Brings to mind the argument that anti-spam measures are a plot of the Lumber Cartel, who want to eliminate the competition for paper advertisements. Short Brigade Harvester Boris (talk) 09:12, 16 June 2012 (UTC)

c 79.180.156.254 (talk) 08:51, 16 June 2012 (UTC)

Medeis (μηδείς) has a clear ideological perspective, allow me to also contribute my own. Purveyor bagging of goods constitutes an element of both productive labour (in the sense of producing a commodity, including its commercial transport and marketable status), and of non-productive labour (or mere circulation). When large scale externalities are first recognised, such as the aesthetic detriments of a landscape clouded with slowly biodegrading bags, these externalities are usually inflicted upon wage earners in the form of profits, by incorporating the externality as a cost onto an existing product. Both paper and plastic are equally detrimental, but (in my market) explicit rather than implicit pricing of bags is proceeding on the basis that workers will put up with bearing the costs of externalities by being gulled regarding their appropriate share of social remuneration. Medeis is correct to the extent that unincorporated externalities ought ideally within capital to be commodified and thus bourne, though this disagrees with the sociology of "actually-existing capitalism." If the externalities are fully incorporated then the environmental costs of plastic bags will be fully represented in the price, and each consumer will be forced to ask herself the question "how much of my grandchildren's life can I ammortise for my plastic bag?" In reality, externalities are usually solved by parliamentary management in private interest; so enjoy paying a plastic bag tax because no court will accept suit on your grandchildren's enjoyment. Fifelfoo (talk) 09:26, 16 June 2012 (UTC)

I am afraid that this is going off target again. Fifeloo says " Both paper and plastic are equally detrimental" but where is the proof? Rmhermen (talk) 13:51, 16 June 2012 (UTC)

In Norwegian experience householders can be expected to sort trash at source and a system of colour-coded plastic trash bags has been introduced: GREEN for biodegradeable kitchen waste, BLUE for recyclable plastics and WHITE for remaining wastes. A cost/benefit factor being investigated is COST of producing special bags (offset by sale at an attractive price to consumers) contra the BENEFITS of easy automatic sorting of the trash categories by optical means and of straightforward Recycling of the already isolated plastics (including the blue bags themselves). Over time another benefit will be reduced and less heterogenous landfills. Note that no banning or enforcement is involved here, only willing participation by environmentally conscious Norwegians. DriveByWire (talk) 15:16, 16 June 2012 (UTC)

The BBC website given above answers most of the questions and seems to suggest that Ireland's bag tax is the most effective solution, but the one thing it doesn't mention is that plastic bags are made from petroleum. According to http://fooddemocracy.wordpress.com/2008/07/16/plastic-bags-and-oil-consumption/ (which isn't perhaps the most reliable source but it does give its own sources) "it takes about 430,000 gallons of oil to produce 100 million plastic bags, and the U.S. goes through 380 billion of them a year...more than 1.6 billion gallons of oil are used each year [in the US] for plastic bags alone." You could reduce the carbon footprint in the manufacture of alternatives by using renewable energy sources but you can't get away from using oil to make plastic bags. Richerman (talk) 00:27, 17 June 2012 (UTC)

A huge part of the problem is that bags are given away. The customer feels he didn't ask for the bag. It is more of a nuisance than a value. It has almost no reuse value, and for every one he does reuse there are a dozen more ugly ripped bits of trash cluttering up the place. He is basically invited to litter.

There are various solutions. One solution is a return deposit. You can't find an empty soda bottle on the streets of NYC for the life of you. They bear a 5c deposit and even if the causal user throws his away a homeless person will collect the empty can before it reaches ambient temperature. Or store should be required to charge for bags up front. A local discount grocery I use does not give free bags but they do sell sturdier plastic bags at 5c a piece. Customers tend to reuse these and I have yet to see one littering the street.

Simply giving plastic bags away for free is indirect littering by the business. If a store were to give away free bananas and the streets were littered with peels and cars windshield were belted with fruit by children we wouldn't argue that the store has a free-market right to give them away--we would hold them responsible for the nuisance. Plastic bags should be treated the same way.

μηδείς (talk) 00:47, 17 June 2012 (UTC)

Plastic bags are used in my house (well, outside it really) for collecting dog poo. A perfect second use. I note, of course, that the supermarkets will sell me plastic bags for this very purpoonese, but why would I bother? HiLo48 (talk) 01:05, 17 June 2012 (UTC)

Meaning future paleontologists are going to wonder why those coprolites came surrounded by petroleum derivatives? I hope your dog only uses a very small fraction of the number of bags I suspect might come into a household daily. I have to fight not to be given a bag when I purchase a gallon of milk in a plastic container with its own handle. μηδείς (talk) 03:29, 17 June 2012 (UTC)

When I rock up to the checkout with three items, I say to the checkout chick, "I don't need a bag. I got these this far without one." HiLo48 (talk) 03:34, 17 June 2012 (UTC)

What gets me is how they insist on putting the meat (which is already completely sealed) in a separate plastic bag, and the milk/dairy products (ditto) in a separate plastic bag, and the laundry/bathroom items (ditto) in a separate plastic bag, but then they also sometimes ask would I mind if they put these things in the same bag if there's not many items in total. Why would I mind? They were all together in the shopping trolley, so why would one be worried about having them together in the same plastic bag? It's insanity gone mad. -- ♬ Jack of Oz ♬ ^{[your turn]} 12:30, 17 June 2012 (UTC)

Bring your own bag, dammit. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:06, 17 June 2012 (UTC)

What's your bag made from? What happens to it when it wears out? HiLo48 (talk) 05:28, 17 June 2012 (UTC)

Plastic. When it wears out, my supermarket are obligated to replace it for free, in exchange for which I have to give them the worn out one, which they recycle.

This comes back to the whole point that plastic bag bans are indeed generally not "worth it", and indeed are extremely rare. The question of what material is used for the bag is irrelevant. The point is to eliminate the mass waste and pollution that is caused by supermarkets giving out free disposable bags (plastic or paper or anything else) which are generally only used once. --Demiurge1000 (talk) 08:04, 17 June 2012 (UTC)

I still remember "the good old days" when everyone had their own string bags. Sure, there wasn't the range of items available that we have nowadays, but shopping for a family of six was still a major operation. But our families managed very well, ate very well, and plastic bags didn't exist, let alone be a massive environmental problem. Can't we turn the clock back? -- ♬ Jack of Oz ♬ ^{[your turn]} 12:30, 17 June 2012 (UTC)

A strict plastic bag ban would not be justifiable, since there are too many things for which a plastic bag works best, as plastic is waterproof, durable, takes up little space, and cheaper than alternatives.

When plastic bags are compared to paper bags for ordinary use at checkouts, their relative desirability depends on what's going to happen to the bag. If the bag becomes litter, the paper bag is far more desirable, since it will decompose quickly, while the plastic bag is long-lasting, unsightly, and harmful to the environment. If the bag is to be properly disposed of in a landfill, however, the plastic bag's advantages come to the fore: It has consumed fewer resources in manufacture, it takes up less space in the landfill, and while it will not decompose in the landfill, neither will the paper in this anaerobic environment. However, this also means that paper is the more effective form of carbon sequestration. John M Baker (talk) 14:36, 17 June 2012 (UTC)

There are reports that unwashed reusable bags are carrying E. coli and Listeria. μηδείς (talk) 18:35, 18 June 2012 (UTC)

Not at your link, at least. What you find there is pure speculation - not even a complete anecdote. That does not mean it cannot happen, but it does not seem to be a significant problem. --Stephan Schulz (talk) 23:40, 18 June 2012 (UTC)

Warmth from friendships

[4] is what's said in this article scientifically verifiable? — Preceding unsigned comment added by 176.250.196.132 (talk) 09:54, 16 June 2012 (UTC)

The article says "They found people felt up to 2C (3.6F) warmer" (my italics), not that they became warmer. That word is crucial; I doubt whether they could scientifically verify those people's feelings.--Shantavira|^{feed me} 12:32, 16 June 2012 (UTC)

A report on the average subjective response from a population can be scientifically verified by a new survey where one has documented steps to lessen the influence of the prejudices and unintentional physical cues on the results (the placebo effect, observer bias, and experimenter's bias). Random assignment of the subject to the experimental or control group is a critical part of a double-blind trial. The key that identifies the subjects and which group they belonged to is kept by a third party and not given to the researchers until the study is over. DriveByWire (talk) 14:52, 16 June 2012 (UTC)

There are two types of experiments that could be done:

1) Check whether their actual core body temp changes by that much. I can tell you right now, though, that it won't. A slight temp diff due to having another warm body near yours radiating heat might exist, as might burning energy while talking, etc., but the temp diff they gave would put you in the fever range.

2) Check to see if they would adjust the thermostat by that much. This is possible, although that still seems like a bit much, too me. StuRat (talk) 20:04, 16 June 2012 (UTC)

Weight training science

Whats the scientific difference between doing low weights and a lot of reps, and high weights and less reps. Whats the difference in what happens to the muscles, physically and chemically? 176.250.196.132 (talk) 10:18, 16 June 2012 (UTC)

Lots of reps with low weights may qualify as aerobic exercise, which is good for cardiovascular health, and may also help muscles grow, while a small number of reps with heavy weights is more of your classic weight training, which develops big muscles, but is not good for cardio. StuRat (talk) 19:59, 16 June 2012 (UTC)

It's actually quite a difficult question to give a good answer to, and there are several theories. Our article on muscle hypertrophy makes an attempt at explaining what happens -- basically the story is that the two types of manipulations affect muscles in different ways, but nobody knows for certain why. Looie496 (talk) 20:31, 16 June 2012 (UTC)

It also affects recovery time, which in turn affects frequency. Dru of Id (talk) 04:36, 20 June 2012 (UTC)

Why don't tightrope poles go much lower?

Like at least 10 feet below the wire, maybe with weights at the end if it's not already too heavy. It would be more of a pi or uppercase omega shape instead of "somewhat bended horizontal stick". Or would that make it too easy? Sagittarian Milky Way (talk) 19:07, 16 June 2012 (UTC)

I believe you want a high moment of inertia about the axis parallel to the wire, through the CG of the tightrope walker. This makes for the best counter balance. To make this as high as possible, while keeping the weight of the pole manageable, you want a long horizontal pole, possibly weighted at the ends. The bending down a bit at the ends may either be to bring the pole down to their CG point or just because making the pole stiff enough to resist bending under it's own weight would make it too heavy. StuRat (talk) 19:56, 16 June 2012 (UTC)

Our tightrope walking agrees with the moment-of-inertia idea and also with lowering of center-of-gravity. If you lower the CG enough, say to the level of the wire or lower, it certainly becomes trivially easy. The unicycle-on-a-wire variant with a heavy below-the-wire weight (for example, [5]) is damn near impossible to tip over even intentionally. DMacks (talk) 20:16, 16 June 2012 (UTC)

Chemistry in cooking and baking

Do cooking and baking involve chemical reactions? 65.92.7.168 (talk) 23:59, 16 June 2012 (UTC)

Yes. Thousands of them. It's a major branch of chemistry, and hundreds of books and thousands of articles have been written about it. See our article: Molecular gastronomy. Dominus Vobisdu (talk) 00:01, 17 June 2012 (UTC)

More broadly, food science would be a good place to start. Molecular gastronomy refers to weird, modern cooking techniques using odd chemistry. Actual cooking chemistry is covered in food science in general. One particularly important set of chemical reactions in cooking are the Maillard reactions. --Jayron32 01:12, 17 June 2012 (UTC)

The reaction of baking soda with an acid to produce bubbles that make bread fluffy is another big one (yeast is another way, but that involves many chemical reactions, being a living organism). StuRat (talk) 01:17, 17 June 2012 (UTC)

As is the simple process of boiling. Plasmic Physics (talk) 01:33, 17 June 2012 (UTC)

Boiling is not a chemical reaction.--Srleffler (talk) 03:10, 17 June 2012 (UTC)

Boiling is not a chemical reaction but it can drive chemical reactions and especially irreversible processes like the denaturing of proteins. μηδείς (talk) 03:15, 17 June 2012 (UTC)

I meant that. Plasmic Physics (talk) 04:48, 17 June 2012 (UTC)

If a hen egg is heated, don't chemical changes occur, in that the protein molecules reform into longer chains somehow? Edison (talk) 03:52, 17 June 2012 (UTC)

Not longer chains per se but more cross-linked. I am surprised you didn't read the link I provided directly above which not only addresses your question but shows a cooked egg.μηδείς (talk)

You are "surprised" that another editor did not automatically know that "denaturing of proteins" is what happens when an egg is heated, so that if interested in eggs he would read the link? It is backward logic. One does not necessarily read every single link that everyone else puts up, when it has no obvious connection to one's interest. Edison (talk) 20:32, 19 June 2012 (UTC)

They aren't technically more cross-linked, but the chains change from wadded up in nice little balls to extended chains, and when extended, they tangle with each other far more. Ergo, the egg white becomes stiffer. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:01, 17 June 2012 (UTC)

Au contraire, they do indeed become more cross linked at points such as where sulfur bearing amino acids like cysteine and methionine allow bond substitutions. That is why hard boiled, well fried, burnt, and rotten eggs smell of the released sulfur. It is complicated and depends on the heat achieved, but while the chains themselves may unwind they don't grow in length, just tangle and perhaps crossbind. μηδείς (talk) 04:17, 17 June 2012 (UTC)

Translate the French, please. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:58, 17 June 2012 (UTC)

There are other sites on the internet, you know... -RunningOnBrains^(talk) 15:35, 17 June 2012 (UTC)

"On the contrary" or "to the contrary." Plasmic Physics (talk) 05:08, 17 June 2012 (UTC)

Browning (food process) involved many well-studied (and not-so-well-studied) chemical reactions. Yeast causes rising by the chemistry of metabolism. DMacks (talk) 16:21, 17 June 2012 (UTC)

Orgasms

Why are female orgasms produced mainly by stimulation of the clitoris, which is not typically stimulated during sex? Wouldn't it be better for female orgasms to be produced by stimulation of the vagina? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 04:10, 17 June 2012 (UTC)

What do you mean "better for"? Nature works with what she has to maximize reproductive success, not engineering elegance or male or female pleasure. Men should ride up high on women during missionary style sex to stimulate the woman's clitoris with their montes pubes and give a reach around (or under) when they do it doggy style. μηδείς (talk) 05:21, 17 June 2012 (UTC)

Whoop whoop is bored again. I'm sure he's heard of the g-spot. Has he not asked his lady what she actually likes? Wickwack05:43, 17 June 2012 (UTC) — Preceding unsigned comment added by 60.230.236.237 (talk)

Firstly, I am less than fifteen years old and therefore have never had sex with anyone. Secondly, Orgasm#Clitoral and vaginal variabilities states, "Research, including research by Shere Hite, has found that 70–80% of women achieve orgasm only through direct clitoral stimulation". Five references are provided. Need I say more? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 06:33, 17 June 2012 (UTC)

Ok. But the answer is likely to be the one given above. The parts of the anatomy under discussion are multi use and in evolutionary terms surviving childbirth is more critical than the women enjoying sex. Also evolution does not start with a blank sheet of paper; it works by adaptation. --BozMo talk 07:13, 17 June 2012 (UTC)

Is there a template to collapse this discussion? Explicit comments may be necessary, but tact would be appreciated. I'm not asking for censorship, I just find it distasteful. Plasmic Physics (talk) 06:53, 17 June 2012 (UTC)

There is often no logic in evolution, which is how women came to be the shape they are. Is there clear evidence that orgasm is required to for a woman to become gravid? There are lots of examples of evolution not developing the most "logical" outcome in human development, check out the vermiform appendix or the recurrent laryngeal nerve. "wouldn't it be better if" only really applies to the survival and improvemment of the funtion of an organism. Orgasm is a pleasurable adjunt, but is it necessary. @Plasma Physics - there is no obligation on your part to read the replies. Richard Avery (talk) 07:32, 17 June 2012 (UTC)

Wow, didn't know gravid was a word in English. Gravidă means "pregnant" in Romanian too. 92.80.39.255 (talk) 10:04, 17 June 2012 (UTC)

Yes, well, I can't unread a post can I? If there was such a template, I would have decided not to read it. Plasmic Physics (talk) 11:00, 17 June 2012 (UTC)

Maybe the OP could get some information by reading this. He may also find this one interesting. (In order to preserve Plasmic's sensitivities I'll refrain from an explanation here. Quite strange that an older woman finds this topic unremarkable but it makes a younger man blush.) --TammyMoet (talk) 11:38, 17 June 2012 (UTC)

That xx % can accomplish something with the technique A leaves out other techniques not mentioned and that may be possible. It sounds anecdotal from a scientific method perspective. I would say there are a variety of other techniques that doesn't involve the main area mentioned. Some takes longer time but gives better result. Electron9 (talk) 17:04, 17 June 2012 (UTC)

It's interesting that there's an implicit assumption throughout this discussion that the destination, so to speak, is much more important than the journey. As is the assumption in the initial question that neither of the parties are in possession of hands; I suspect this is just down to a lack of experience on the part of the OP, which is fair enough. Brammers (talk/c) 09:36, 18 June 2012 (UTC)

Since I can't imagine what PlasmaPhysics finds offensive here other than "do it doggy style" I will not be offended if someone who knows the technical term for it replaces the phrase in my answering post and provides a link. μηδείς (talk) 17:39, 17 June 2012 (UTC)

You can say it in Latin - "coitus more ferarum" (sex in the manner of animals). Our article is at doggy style, though. The reference desk does not censor serious discussions of topics that some people find offensive, so PlasmaPhysics will just have to stay away if he has a problem with it. --Tango (talk) 17:44, 17 June 2012 (UTC)

But when as here the OP is at law a Minor responders do so In loco parentis. Freedom from censorship here in Wikipedia does not grant a carte blanche to hand out gratuitous advice that can shape the OP's future Reproductive health. Sex education is not Wikipedia's business, see WP:NOTHOWTO.

In any case, that is not what I asked. I asked why this is so, not how to circumvent this being so. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 18:57, 18 June 2012 (UTC)

Your second question does suggest you have an idea for improving the arrangement. DriveByWire (talk) 22:13, 18 June 2012 (UTC)

As to what might be "better" in female biology, a small boy once thought women should have evolved with two depressions in their back at breast height. That improvement would allow women to stand closer together in queues and save standing space. DriveByWire (talk) 14:26, 18 June 2012 (UTC)

That small boy obviously had not realised that communism has only been around for ~100 years, and only in certain countries, not enough to have driven any evolutionary change. Wickwack121.215.74.128 (talk) 16:07, 18 June 2012 (UTC)

Why this is so has to do with the fact that developmentally the genitals differentiate from a common starting point development of the reproductive system and the genes that make the genitals have to pass down through both males and females. Biology can't start from scratch in each. The genes that make the clitoris in the mother make the glans penis in her son. So, since sensitivity of the glans in males is so important, it carries over to the female clitoris, which is the homologous organ. Also, the fact that a man has to work at pleasing a woman works as a sort of sexual display indicating that he might be helpful in general as a mate rather than only centered on his own gratification. But that's a side effect, not the reason why the clitoris evolved that way. μηδείς (talk) 19:28, 18 June 2012 (UTC)

And the scrotum is the homologous organ of the other parts, thus explaining the comparative insensitivity. Sagittarian Milky Way (talk) 23:58, 18 June 2012 (UTC)

A citation is needed for that alleged side effect. The clitoris provides the male with an externally accessible means of preparing the female before vaginal penetration, see Foreplay. Compare with Doorbell. DriveByWire (talk) 22:09, 18 June 2012 (UTC)

Maybe some apemen were too dumb to do this, yet another of the numerous pressures that select against stupidity. Speaking of intelligence, spatial intelligence is very helpful in both hunting (which was his main job) and sex. Sagittarian Milky Way (talk) 23:58, 18 June 2012 (UTC)

I've often thought that the birth control pill introduces a strong selection pressure against women having a good memory. 203.27.72.5 (talk) 01:34, 19 June 2012 (UTC)

How so? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 11:56, 19 June 2012 (UTC)

He means that forgetful women are more likely to forget to take the pill and thus have more children. Unlikely. The pill forgetter can fall back on emergency contraception, abortion, IUD, implants. She will have 2.4 children like her careful sister. Itsmejudith (talk) 21:22, 19 June 2012 (UTC)

Betadine and hydrogen peroxide

Is it safe to mix Betadine and hydrogen peroxide? I did this and it made this weird smell that made my nose burn.--Wrk678 (talk) 08:24, 17 June 2012 (UTC)

Probably not then :) --Gilderien Chat|List of good deeds 09:53, 17 June 2012 (UTC)

Betadine is an iodoorganic compound, so peroxide may oxidise iodide and release iodine vapour. Plasmic Physics (talk) 11:06, 17 June 2012 (UTC)

See here. Iodine vapour could cause damage to your eyes and throat.--Gilderien Chat|List of good deeds 11:20, 17 June 2012 (UTC)

If you're doing something which gives off a gas that makes your nose burn, you should probably be doing it in a fume cupboard. If you have access to a fume cupboard, then you probably have access to people that can give you more reliable answers on this kind of thing than random people on the internet. --Tango (talk) 17:55, 17 June 2012 (UTC)

As I understand it, betadine contains iodine, not iodide, so the logic of the responses above is questionable. Looie496 (talk) 00:32, 18 June 2012 (UTC)

Actually it contains the triiodide anion which decomposes to give iodine and iodide. Plasmic Physics (talk) 00:39, 18 June 2012 (UTC)

Our betadine article agrees. DMacks (talk) 03:44, 18 June 2012 (UTC)

I'm not sure why you ask, but if you're doing it for cleaning skin or something [6] seems to suggest it's not a good idea although I'm not sure what the article actually says as it's not available online or in the library for me and I'm not going to bother with a request, in any case I suggest you consult an appropriate health professional. If you are cleaning wounds, I suggest you consult an approproate health professional like a pharmacist as sources like [7] [8] suggest it's not always a good idea to use either product. Speaking generally, note that just because two compounds have similar effects doesn't mean mixing them would generate an even better product, in particular generally it's a bad idea to mix different cleaning products unless you know what you're doing. Nil Einne (talk) 04:57, 19 June 2012 (UTC)

Above it is stated that Betadine contains the triiodide anion. Would Nitrogen triiodide be produced if Betadine were mixed with some common household chemical? Edison (talk) 20:12, 19 June 2012 (UTC)

Probably not, because triiodide is not the same as triiodide. The triiodide here, is: Diiodidoiodate(1-). Plasmic Physics (talk) 22:25, 19 June 2012 (UTC)

giraffes

There's a line in the Recurrent laryngeal nerve article which says; "The extreme detour of this nerve (about 15 feet in giraffes)[2]". Er.. measurments in giraffes is a thing? — Preceding unsigned comment added by 88.173.200.107 (talk) 17:48, 17 June 2012 (UTC)

No, the nerve is in a giraffe. They are measuring in feet. --Tango (talk) 18:05, 17 June 2012 (UTC)

And its measurement in giraffes is notable (vs in other species). DMacks (talk) 18:11, 17 June 2012 (UTC)

It's not the best English. I've changed it to "about 15 feet in the case of giraffes". (Please don't ask how many giraffes are in the case.)--Shantavira|^{feed me} 07:38, 18 June 2012 (UTC)

lump

What is the lump on this gooses head?

That part of the beak is called the cere. In most birds it's not noticeably swollen, and is not always so even in this or closely related species. The colour of the cere is used by some bird species (more obviously in males) to exhibit their physical health and hence sexual desirability, so I'd hazard a guess (but others may know better) that the swelling is an additional seasonal sexual signal in this species. {The poster formerly known as 87.81.230.195} 90.197.66.109 (talk) 18:36, 17 June 2012 (UTC)

Modified your links a bit. DRosenbach ^{(Talk | Contribs)} 12:22, 19 June 2012 (UTC)

Goose imprinting

If a goose is raised in a completely sterile environment like a white room, with nothing consistent (ie food bowl, bedding, etc regularly changes appearance) what would it imprint on? Or does it just go mad?

According to Imprinting (psychology), they imprint on moving objects (which can include inanimate objects that are made to move) within the first few hours after hatching, so I don't think regularly changing the contents of the room is necessary. In that situation, I think they just wouldn't imprint on anything. Quite what effect that would have on them, I don't know. Quite possibly none. --Tango (talk) 18:02, 17 June 2012 (UTC)

They experimented that moving inanimate objects work yet didn't try this? Sagittarian Milky Way (talk) 23:45, 18 June 2012 (UTC)

You'd have a hard time getting that past the ethics committee these days. LukeSurl ^{t c} 21:41, 19 June 2012 (UTC)

June 18

Rhenium

Why is rhenium so rare? Double sharp (talk) 04:11, 18 June 2012 (UTC)

My guess would be: because it has an odd atomic number, and is not frequently produced by nucleosynthesis during supernovae. Plasmic Physics (talk) 04:19, 18 June 2012 (UTC)

It's very dense (21.02g/cm3) so it probably sank to the core of the Earth when it was still molten as did iridium. Also like iridium, it is very siderophilic, so it "likes" to dissolve in molten iron e.g. the Earth's core. According to [9] it's only rare on the Earth's surface, not in the universe as a whole, so that rules out Plasmic Physics's hypothesis. 203.27.72.5 (talk) 04:36, 18 June 2012 (UTC)

Rarity is relative. Plasmic Physics (talk) 04:48, 18 June 2012 (UTC)

Touché. It could indeed be rare compared to other elements in the universe, but especially rare on the Earth's crust due to the processes I described. I can think of lots of elements with odd atomic numbers though, and many of them are not rare at all. 203.27.72.5 (talk) 05:10, 18 June 2012 (UTC)

According to Synthesis_of_precious_metals#Rhenium, ¹⁸⁵W and ¹⁸⁷W are formed from the irradiation of naturally occuring tungsten with neutrons (readily available in stellar conditions) and these decay into ¹⁸⁵Re (stable)and ¹⁸⁷Re (half-life 10¹⁰ years). So it may be generated in high metallicity stars. 203.27.72.5 (talk) 06:10, 18 June 2012 (UTC)

Estimated abundances of the chemical elements in the Solar system.

It is not that rarer than the other similar metals, but its chemistry is not leading to a strong enrichment in any minerals and therefore tit is hard to extract. Only Molybdenum ores contain significant amounts of rhenium. --Stone (talk) 10:01, 18 June 2012 (UTC)

"It is not that rarer than the other similar metals"

Don't forget that this graph is a logarithmic scale, so it really is a lot rarer than most elements; just estimating from the graph I'd say it's the 4th least abundant non-radioactive element. It's almost 10 times less abundant in the universe than gold.

Uranium and the late REE are less abundant but they are produced in considerable larger quantities. The amount the solar system and the amount we can extract are two very different things.--Stone (talk) 06:22, 19 June 2012 (UTC)

Also, to the IP above, note the trend in the graph with the odd-numbered elements: due to the Pauli exclusion principle, they are less abundant on average (save Hydrogen of course), and Rhenium is one of the heaviest stable elements, well beyond Iron-56, which is the last element which can be sustainably produced in stellar nucleosynthesis. I had never heard of the Goldschmidt classification though, clearly this plays a role in its rarity in Earth's crust. Thanks for the interesting read! -RunningOnBrains^(talk) 12:37, 18 June 2012 (UTC)

If the subject of the origins and abundance of the elements interests you, I highly recommend P. A. Cox's The Elements: Their Origin, Abundance, and Distribution http://www.amazon.com/The-Elements-Origin-Abundance-Distribution/dp/019855298X which is perhaps the most fascinating and well-written science books I have ever read. I cannot recommend it strongly enough. μηδείς (talk) 17:04, 18 June 2012 (UTC)

Bird song identification

Just wondering if anyone out there can either identify a bird from a transliteration of its song, or point me at a site that can? Quite high pitched "didit, didit, didit" - UK Midlands. --TammyMoet (talk) 09:55, 18 June 2012 (UTC)

It's possibly a member of the Titmouse family - the name "tit" imitates the sound they make, as well as providing humerous material for many Carry On films. You can hear a Great Tit in this YouTube recording. Alansplodge (talk) 12:55, 18 June 2012 (UTC)

In the end I played my Bird Songs CD and they identified it as a wren. Personally I thought it may be a song thrush given the repetitive nature of the call, but I'll go with a wren. I hadn't heard it before, but I felt sure I'd seen it in a bird identification book. --TammyMoet (talk) 14:33, 18 June 2012 (UTC)

Xenon diiodide and krypton dibromide

Shouldn't xenon diiodide and krypton dibromide both exist, as they are isoelectronic with, respectively, the triiodide and tribromide ions? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 13:03, 18 June 2012 (UTC)

As you were told the last time you asked "why does/doesn't X given Y that is isoelectronic with it", you need to consider things like charge, electronegativity, etc. and also do a literature search before claiming something doesn't exist. That literature search would often reveal why not, as part of studies of analogous compounds. People really do study and publish "let's extend a known series into not-yet-known territory" articles on a regular basis--both of your proposed compounds have been studied (one even experimentally). DMacks (talk) 16:20, 18 June 2012 (UTC)

• I really doubt these exist, given the low electronegativities of iodine and bromine. Xenon has an electronegativity of 2.6, so iodine and bromine (2.4 and 2.8 respectively, I believe) don't have the muscle to get xenon in a bond setup.--Jasper Deng (talk) 16:29, 18 June 2012 (UTC)

One is a known excimer complex; it indeed does have a very short lifetime and readily decomposes to the elemental forms. DMacks (talk) 16:36, 18 June 2012 (UTC)

Which one? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 18:53, 18 June 2012 (UTC)

Prospective ligands around xenon has to be sufficiently electronegative to tease out an atomic obital to leach onto. Xenon has a pretty stable ground state arrangement of atomic orbitals, it's not going to sit iddle, while an unwelcome guest is trying to take advantage of it - it's going to fight it, and look for the first opportunity to get rid of it. Bromine and iodine are too weak to contend with a heavy weight like xenon. Plasmic Physics (talk) 23:40, 18 June 2012 (UTC)

If my explaination seems a bit abstract, it's because I anthropomorphise my molecules and atoms, I give them personalities and character. Their behaviour is easier to visualise that way. Plasmic Physics (talk) 00:18, 19 June 2012 (UTC)

Plasmic, I'm concerned about your explanation. A quick glance at a descriptive chemistry textbook (in my case, Greenwood and Earnshaw's Chemistry of the Elements, 1st ed.) shows that xenon displays extensive chemistry, with oxidation numbers of +2, +4, +6 and +8 and a full range of coordination numbers from 0 to 8, and that xenon dibromide and xenon dichloride had also been detected by 1986. The chemistry of krypton, however, was much less developed at the time of writing, with only KrF₂ and a handful of complexes being known. From what I can recall of lectures from a couple of years ago, krypton chemistry still lags behind, argon is restricted to a couple of highly unstable compounds and neon is still effectively inert: using xenon as your example of non-reactivity might not be the best choice. Brammers (talk/c) 09:22, 19 June 2012 (UTC)

I didn't say that it was non-reactive, I said that it is one tough customer, that doesn't like sharing, not that it can't. Plasmic Physics (talk) 10:13, 19 June 2012 (UTC)

Interesting that Kr and Xe are less electronegative than several of the halogens (and even O and N!)--things with which halides form moderately stable compounds. DMacks (talk) 10:32, 19 June 2012 (UTC)

Electronegativity is only realy applicable when discribing the relationship between atoms in a bond, first you have to form the bond. Plasmic Physics (talk) 10:57, 19 June 2012 (UTC)

Clues to calculate sun's future

Average people would thik when sun dies nobody knows, but scientific forecast, figuring out what will happen to our solar system in billions of years future is quite easy, not like what non-educated peoples might think. I wonder how do scientist come up with these variables, maximum size of the giants, net of sun's mass loss, how much longer they have on main sequence. Do they send a spacecraft to another stars, or astronomers basically use special powered telescopes? I thought when they send a spacecraft to another stars, then they are able to get these informations quite easily. What makes the informations fuzzy? Spacecraft? The technologies on spacecrafts are usually pretty strong on collecting informations? or to look at foreign stars/solar system they use a special powered telescope, which the variables like maximum giants radius, net star's mass loss might be sketchy causing scientist to come up with countless of different stabs. Does the data memory depend on how far away they are from our solar system? Further away they are from our solar system, do the virtual data memory get weaker? --69.226.45.94 (talk) 21:17, 18 June 2012 (UTC)

We are a long way from being able to send spaceships to other stars. They are so far away that any crew would be dead, and the ship would be out of energy, long before it arrived at even the closest star (beyond the Sun). StuRat (talk) 21:20, 18 June 2012 (UTC)

Almost all of our knowledge of other stars comes from stellar spectography. Even helium was discovered by this method. μηδείς (talk) 21:51, 18 June 2012 (UTC)

You mean, helium outside our solar system was discovered by this method, right? 203.27.72.5 (talk) 22:09, 18 June 2012 (UTC)

Nope, you meant what you said. That's pretty amazing. 203.27.72.5 (talk) 22:11, 18 June 2012 (UTC)

The furtherest man made object from Earth is Voyager I which is not heading towards any particular star, but will pass within 1.6 lightyears of AC+79 3888 in about the year 42000. Voyager II will pass by Sirius in about the year 300000. Pioneer 10 would take until the year 2000000 to reach Aldeberan but it probably won't get there anyway. Pioneer 11 is headed vaguely in the direction of Scutum. Is hasn't arrived there yet, but when it does, I'll let you know. 203.27.72.5 (talk) 22:07, 18 June 2012 (UTC)

As the others point out, our predictions about the solar system are largely based on observations made from earth. The space probes and things like the Hubble telescope also contribute information. This tells us about the way things (probably) are in the solar system. To predict the future, scientists take this information and feed it into mathematical models which are based on physical laws. But all models are "wrong", in the sense that they make simplifying assumptions, and all of our observations of the universe have errors and "noise" in them. Me, I'm still amazed this stuff is accurate and precise enough to put a man on the moon :) SemanticMantis (talk) 22:27, 18 June 2012 (UTC)

I've read before that all of the Apollo missions were possible without any relativistic corrections to the Newtonian mechanics. In that regard I don't think putting a man on the moon needs such great accuracy in the underlying physical models. 203.27.72.5 (talk) 22:34, 18 June 2012 (UTC)

We had yellow stars, maybe tons of it which have came off the main sequence, and collapse into white dwarf. I thought scientist use the same model what happened to similar sun-like stars, and use that to see what will happen to our sun. i wonder if you ever thought about that.--69.226.45.94 (talk) 23:18, 18 June 2012 (UTC)

Stellar evolution is far too slow to observe, save for the dramatic nova and supernova events. We can draw similarities between the states of all different stars in the sky, then sort them into categories, and then apply theory from the known physical properties of matter and energy to generate hypotheses on which categories of star result from what conditions. The main variabilites in stellar condions are mass, metallicity, temperature and age. Theories that prove useful in explaining the different observed states of stars allow us to model stellar evolution and then, by constructing a model using the current age, metallicity and mass of our star, we can make some assumptions about how it's evolution may progress.

We don't watch main sequence stars become white dwarfs. We see white dwarfs and we see main sequence stars and we hypothesise that white dwarfs develop from main sequence stars through mechanisms that we propose. We then collect evidence to support these hypotheses in the form of spectral data (chemical composition), brighness measurements (temperature), etc. 203.27.72.5 (talk) 23:34, 18 June 2012 (UTC)

HV Electrical transformers - do they really need a hand to help them go bang?

Hi. I'm watching a video on Youtube in which a High Voltage transformer block on a power pole overheats, and promptly explodes in a complete mass of hell. My question to the desk is this: Why do the companies who make these things see fit to fill them with something explosive to keep them cool and happy?

If they overheat or flat out short, they (can, and often do,) explode - and mineral oil & the coolants used are highly explosive, which only seems to add "fuel to the fire", so to speak. Is this a design flaw, or are there really no alternatives to the inclusion of such highly combustible materials in the making of these products?

 BarkingFish  23:03, 18 June 2012 (UTC)

We have some information in Transformer#Cooling and Transformer oil. There's just not much that is economically viable and has the right thermal properties to be useful (shame PCBs are outlawed). It's also hard to appreciate how much energy there is in an arc flash. There's just not much at all that can withstand it. I should also point out that the materials are not explosive by nature and are not really highly flammable either. But they can be made to burn given a large enough added energy, or to boil just a small enough amount to get a BLEVE. DMacks (talk) 23:40, 18 June 2012 (UTC)

Don't forget the amount of energy flowing from the power line that is capable to power hundreds of households. Which when the electrical characteristics of the transformer fails can end up in a small enclosed container. And easily create something like combined steam explosion and fuel vapor bomb. Electron9 (talk) 04:01, 19 June 2012 (UTC)

See Transformer oil. It insulates and cools transformer windings. There are also air cooled transformers ("dry types"), but they must be securely protected from moisture, may need cooling fans, and do not seem to offer as high a power rating for a given volume and weight. They would fail if rain, snow etc got into the windings, and are not good candidates for poletop use. Transformer says that some dry types are now made in sealed tanks, insulated and cooled by sulfer hexafloride, which sounds like a good idea if the cost is not too high for typical distribution sizes and size and weight are comparable. It would probably be harder to keep a distribution transformer gas-tight for decades than to keep it liquid-tight. The transformer oil is sometimes mineral oil, similar to motor oil. It does not seem to be all that explosive at normal temperatures, but if it is heated above its flash point and sprayed out in little droplets, then you can get an impressive fireball. I have seen a relatively small oil-filled padmount transformer blow open and burn the face off the bricks of a brick wall. PCB was less flammable than mineral oil, but it could produce dioxin in an arcing fire and has generally been replaced. Silicone oil is a replacement which is not very flammable, but I've heard (no ref handy) it can be explosive if it gets contaminated with water. A transformer which steps down 12000 volts to 240/120 volts might well have 10000 amps of fault current flowing into a short or arc inside the transformer, should one occur. This could happen if there is an insulation failure in the windings, if the oil level drops low, if water leaks in when a gasket fails, if overheating due to overloads causes paper insulation to break down and release moisture , if the oil becomes carbonized from tap changer operation or overheating or arcing at loose connections, or even because lightning struck near the transformer. (I have seen 60 year old transformers with oil as dark as coffee), still in use, but utilities do regular tests of the fluid in larger transformers. It could also be caused by a switching error or resonant conditions in a cable-fed system ("ferroresonance"). It is then up to the primary high voltage fuse to interrupt the current before the metal container fails and flaming oil shoots out. High voltage power fuses are cleverly designed, but complicated gadgets. Some have an overcurrent element which melts, causing a strain element to release a spring which causes an arc inside a tube containing boric acid, the ionized particles of which interrupt the arc. This might ideally happen in less than the first half cycle of fault current. Other fuse types can't interrupt until the current hits a zero at the zero point of the sine wave. The vast majority of the time, the primary fuse quickly does its job, and only customers served by the one faulted transformer lose their power, with others only seeing a momentary dimming of lights until the fuse operates. Then a utility lineman shows up in an hour or whatever and tries replacing the fuse and relivening (if there is no obvious damage) in case it was just a weak fuse or a lightning glitch. If the transformer won't reliven, then the lineman calls for a replacement transformer, and in a city, might be able to temporarily feed the outaged customers from the next transfomers, if the secondaries extend down the alley. When the transformer fuse fails to interrupt, the thousands of amps of fault current continues to transfer many megawatts of power into the faulted transformer can until the transformer catches fire or an upstream backup fuse operates on a delayed basis, likely killing the power to other transformers as well. Edison (talk) 19:46, 19 June 2012 (UTC)

Mitsubishi makes sulfer-hexaflorude insulated transformers in distribution size and up: [10]. No info on price, mean time between failures, and size/weight for a given KVA capability. Other manufacturers emphasize substation and high voltage gas insulated transformers. Edison (talk) 20:04, 19 June 2012 (UTC)

A common measure of the estimated energy released by an arc-fault is in equivalent amount of TNT, and common values appear to be are on the order of a few pounds per second of arc in the 15 kV primary transformer/switchgear level, down to "only" a few ounces-worth (about a hand grenade or so) for end-user secondaries. DMacks (talk) 20:19, 19 June 2012 (UTC)

June 19

Is there a medical term for the physical feature of a very "triangular" head?

For instance (not to label a living person with something, just to give an example of what I'm talking about), there's this video footage of Arsenio Hall. When he's face-on, you can see the very pronounced pointedness of his head. We humans like to name things, so what about that? 69.243.220.115 (talk) 00:52, 19 June 2012 (UTC)

Hi. While there almost certainly isn't a specific term for the triangular head shape, it is possible that Hall could have been born with a condition known as Craniosynostosis, which causes the bones in the skull to fuse earlier than they should, it's caused by either a failure of the bones to grow correctly, or in some cases, by a failure of the brain to grow.  BarkingFish  01:04, 19 June 2012 (UTC)

Let's invent one: mantis head. :-) StuRat (talk) 01:07, 19 June 2012 (UTC)

I don't think I understand Modulation (music) , but I did have a question about it.

Or may be I don't understand Key (music) either. These are articles that are probably just fine for people with at least some musical background but are incomprehensible for people like me. Lines like "The methods by which the key is established for a particular piece are not easy to explain" or "The key signature is not a reliable guide to the key of a written piece", don't help much either. Could someone add Key (music) (for nerds) that says: "To recognize the key , the software would have find the first note probably played by calculating the average of all notes played and look up the frequency in a table" or something like that? There is nothing in either article that is a recipe to find out if Frère Jacques even has a key or what it could be. The question I wanted to ask is, is http://www.youtube.com/watch?v=OSRCemf2JHc Popcorn modulated at 1:07 but I've come to realise that that would be like a 6 year old asking why the exact value of Pi cannot be written on a piece of paper without understanding multiplication. Joepnl (talk) 01:31, 19 June 2012 (UTC)

I agree that the article is too technical. Here are the basic things it helps to understand. (1) An octave is divided into 12 intervals that are equally spaced in pitch -- the interval between consecutive notes is called a semitone. In other words, there are twelve semitones in each octave. (2) A key consists of a subset of semitones. The two most common types of key are called major and minor. (3) In a major key, the notes are at intervals of 2-2-1-2-2-2-1 semitones. The starting note of the sequence is called the keynote. (4) In a minor key, the notes are at intervals of 2-1-2-2-1-2-2 semitones, starting from the keynote. There are also other kinds of keys with different numbers of notes and different spacing. (5) The easiest way to tell the keynote of a tune is to know that the tune usually ends with that note, or with a chord based on that note. Looie496 (talk) 02:19, 19 June 2012 (UTC)

You can change one major key into another one by changing only one note in it by a semitone. C major is the white notes on a piano keyboard:

     ... C D EF G A BC D EF G A BC D EF G A B ...
     ... * * ** * * ** * ** * * ** * ** * * * ...
     ... \__________/\__________/\__________/ ...

If you shift the star under each F up by a semitone, making it F#, then you get

     ... C D EF G A BC D EF G A BC D EF G A B ...
     ... * * * ** * ** * * ** * ** * * ** * * ...
     ... ______/\__________/\__________/\____ ...

which, as I've marked, is the same repeating pattern of stars, but starting from G instead of C. That's G major. Instead of sharping F, you can flat B, which gets you F major. Those are the only two "directions" you can go from C—other single-semitone changes don't get you the same repeating pattern. If you go in the flat direction from G it takes you back to C. If you keep sharping things from G you go to D, A, and so on. Eventually, after sharping everything, you get to C# major (seven sharps). You can keep going, double sharping the notes until you get to C-double-sharp major (fourteen sharps), then triple-sharping them, etc., but composers don't stray that far from their original key. You'll see the occasional double sharp and that's it. The principle of modulation between keys is that keys like F, C, and G major are close to each other in the sense of having a lot of notes in common, so in principle you can shift imperceptibly between them by altering notes that you happen to not be playing at the moment. Thus the exact moment at which the key changes is not well defined.

Equal temperament is a thing that exists, but it's not especially relevant here. If you want to play a lot of different keys on an instrument that can only play a fixed set of pitches, like a piano, you may want equal temperament. If you're playing an instrument that can produce a continuous range of pitches, like a violin or the human voice, then temperament is meaningless, but you still have this system of related major keys. In equal temperament C and B-sharp and A-triple-sharp and so on are the same sound frequency, but in general they're not the same, because the half steps and whole steps above are not generally all the same size—they are adjusted slightly so that certain intervals between them sound pleasing to the ear. By the time you get from C major (zero sharps) to B-sharp major (twelve sharps) the frequency has shifted a bit—specifically, by a factor of (3/2)¹² / 2⁷ ≈ 1.014. -- BenRG (talk) 07:25, 19 June 2012 (UTC)

Find and listen to Howard Goodall's five-part documentary Big Bangs on the history of music. A large part of his focus is on tone, key and temperament. See http://www.youtube.com/watch?v=AJX76zHAaFA but look for better links. It is quite excellent and will educate you on all you need to know. μηδείς (talk) 05:41, 19 June 2012 (UTC)

(Also, listen to http://www.youtube.com/watch?v=IZ4LCejQg8o μηδείς (talk) 05:41, 19 June 2012 (UTC))

I watched about three minutes of the first one and gave up. I don't see what this question has to do with equal temperament, except in a very indirect way. The second one seems even less relevant, though it is pretty, I guess. -- BenRG (talk) 07:25, 19 June 2012 (UTC)

On propositional logic

In Propositional logic, under the heading of "Basic Concepts", they list the possible cases that may occur when one considers two propositions and an operation "connecting" (in lack of a better term) them, namely:

1 - P is true and Q is true

2 - P is true and Q is false

3 - P is false and Q is true

4 - P is false and Q is false

then, when the operation "material conditional" (P -> Q, read as "if P, then Q") is discussed, the following is written: "(...)It expresses that Q is true whenever P is true. Thus it is true in every case above except case 2, because this is the only case when P is true but Q is not. Using the example, if P then Q expresses that if it is raining outside then there is a cold-front over Kansas.(...)"

My question is: Should case 3 not represent a failure for the operation as well?200.119.78.115 (talk) 01:43, 19 June 2012 (UTC)

No, because there is no statement making the state of P conditional on Q, only vica-versa. 203.27.72.5 (talk) 02:01, 19 June 2012 (UTC)

If you said "Q if and only if P" then 3 would fail.165.212.189.187 (talk) 14:03, 19 June 2012 (UTC)

(EC) No. "If P, then Q" says nothing about whether Q will be true or not in the case of P being false, so case 3 doesn't contradict "if P, then Q". Looking at it another way, if Q is true, then "if P, then Q" doesn't imply anything about whether or not P is true. You can look at the mistake you are making as being the logical fallacy called affirming the consequent. Red Act (talk) 02:10, 19 June 2012 (UTC)

I don't really like the way they wrote that, though, as we don't have enough info to know if 3 or 4 are correct. It should be stated, that "If P is true, then we know that Q is true. However, if P is false, then we know nothing about whether Q is true or false." For a specific example "If it has been raining for an hour, then the ground is wet". However, if it hasn't been raining, that doesn't guarantee that the ground is dry. Snow could have melted, a water main could have broken, etc. StuRat (talk) 02:13, 19 June 2012 (UTC)

And that, StuRat, is why we have the Simple English Wikipedia article on propositional logic. 203.27.72.5 (talk) 02:21, 19 June 2012 (UTC)

It seems that our article is both unnecessarily complex and misleading, I can't see how that's an improvement in any case. And the Simple English version is just a stub and doesn't address this issue. StuRat (talk) 02:25, 19 June 2012 (UTC)

How is it misleading? And I don't think it's unnecessarily complex. It's just rigourous, as demanded by the subject matter. 203.27.72.5 (talk) 02:28, 19 June 2012 (UTC)

I just added to the Simple English version, to cover this case. The portion of logic discussed in this question is quite simple, and yet many probably couldn't understand it reading through our overly complex article. This is true of many of our math and science articles. (There are topics that can't be accurately described in simple terms, like quantum mechanics, but this isn't one of them.) StuRat (talk) 02:42, 19 June 2012 (UTC)

My thoughts on the quality and usability of Wikipedea articles: As time goes on, more and more articles seem to be written longer and longer, and more and more difficult for lay people to asimilate. A large fraction of Ref Desk questions ask things that the OP's could have answered for themselves by consulting relevant WP articles. So why do they ask? Because a) lazyness, b) they didn't think to search, c) they didn't know the terminology to search with, or d) they did consult a relavent article, but it di not answer their question because (1) it didn't cover it or (2) they didn't understand it. Item (d) is significant and we should adress that. I think that if a WP article is longer than about 100 - 150 lines, and/or uses lots of specialised terms (whether linked to term articles or not), there should be a sort of executive summary - a short few paragraphs that 1) give an overview of the deeper coverage to follow, 2) avoid as much as possible the use of specialised terms, 3) allow the reader to decide quickly whether the following content is likley to be of interest/help or not.

In some articles, I also think there should be a standard section "Common misconceptions" - this can significantly improve understanding, and reduce cyclic editing. Common misconceptions in science can range from silly urban myths thru to non-obvious errors in early textbooks that just keep on being copied from one reference to another.

Wickwack121.215.61.16 (talk) 03:32, 19 June 2012 (UTC)

I agree, except that long and complex aren't the same thing. A short article can be utterly incomprehensible, while a long one can make perfect sense. (At some point a long article should be broken into smaller articles, though, just because it's easier to load pages and navigate that way.) For an example of an article where I provided the easy to understand intro, see Weighted mean#Examples. StuRat (talk) 20:49, 19 June 2012 (UTC)

Thanks to RedAct and StuRat for addressing the question, but wouldn't that just imply nothing about the material conditional itself? What I mean to say is that, even though it may be the case that statement 3 doesn't contradict "if P, then Q," statement 3 does not imply anything at all about its truth. The OP.200.119.78.115 (talk) 04:45, 19 June 2012 (UTC)

The fact that it doesn't tell you anything is why it needs to be true. Saying "all ravens are black" is equivalent to saying "for every thing in the world, if that thing is a raven, then that thing is black". The only way to ensure that these statements are equivalent is to make the "if P then Q" part true whenever P is false (in this case, make it true for all non-ravens). If it was false for any non-raven then the whole sentence would be false independently of whether we had found a non-black raven, which wouldn't make sense. Only a non-black raven can falsify the sentence, not any of the other three cases. -- BenRG (talk) 05:51, 19 June 2012 (UTC)

The semantics of the material implication is as it is. If this captures the "intuitive meaning" of a conditional statement, and if not, if there is anything better, has been discussed a lot among philosophers and logicians. At least for propositional logic, the answer sems to be "not quite, but no" ;-). --Stephan Schulz (talk) 10:01, 19 June 2012 (UTC)

Right — it's the closest you can get by looking only at the truth values of the component parts. The natural-language conditional looks at more than that; it also looks at the meaning of the component parts. This is much harder to get at formalistically, but attempts have been made. The OP may want to look at relevance logic for more information. --Trovatore (talk) 21:01, 19 June 2012 (UTC)

Inventory of asteroid contents?

Where can one find an inventory of the contents of asteroids within the asteroid belt, or closer? (iron, titanium, uranium. gold, H3 etc) Electron9 (talk) 03:54, 19 June 2012 (UTC)

Do you want to know what the average elemental composition of the entire population of asteroids is, or do you want a list of asteriods with their individual elemental compositions? And also, what is H3? 203.27.72.5 (talk) 04:16, 19 June 2012 (UTC)

"list of asteriods with their individual elemental compositions?" is the favorite. Ie which asteroid does one select to mine X ..? Electron9 (talk) 13:15, 19 June 2012 (UTC)

H3 is the most common substance in the universe. Evanh2008 ^{(talk|contribs)} 04:18, 19 June 2012 (UTC)

Correction: Most common molecular ion in the universe. Someguy1221 (talk) 04:29, 19 June 2012 (UTC)

Correction: Ions have charges. "H3" (no charge indicated and the 3 is not subscript) doesn't mean anything as far as I can see other than a 2001 film. 203.27.72.5 (talk) 04:39, 19 June 2012 (UTC)

Truer than what I said originally. How about: "H3 is the most common molecular ion of the most common element in the universe"? Evanh2008 ^{(talk|contribs)} 04:31, 19 June 2012 (UTC)

(EC)So H₃ then? I doubt much hydrogen is going to be present on asteroids except as water or ammonia. According to hydrogen it is most commonly found in the plasma and atomic state, not as H₃ or any ion thereof. 203.27.72.5 (talk) 04:36, 19 June 2012 (UTC)

Look up trihydrogen cation. Whoop whoop pull up ^{Bitching Betty | Averted crashes} 11:38, 19 June 2012 (UTC)

The original poster may have meant Helium 3 rather than the very unlikely triatomic hydrogen or H3+ ion. Graeme Bartlett (talk) 13:03, 19 June 2012 (UTC)

Correct :-) Electron9 (talk) 13:15, 19 June 2012 (UTC)

So ³He then? Not very likely on asteriods other than as a product in a decay chain, so very trace amounts. Anyway, I still don't know what the OP is asking for, a catalogue of asteriods with their individual compositions, or the abundance of chemical elements in the solar system's asteriods in general. 203.27.72.5 (talk) 20:45, 19 June 2012 (UTC)

There's presumably He-3 on asteroids for the same reason it's on the moon - they've been bombarded by solar wind for billions of years and it builds up. --Tango (talk) 21:55, 19 June 2012 (UTC)

Which, from the article on He-3, is present only at ppb levels, and it's the product from tritium beta decay. 203.27.72.5 (talk) 22:47, 19 June 2012 (UTC)

milk and aging?

have there been any studies on whether consumption of milk affects aging? 99.43.78.36 (talk) 04:14, 19 June 2012 (UTC)

I can't speak to studies, but it's high in lactose so bad for diabetes and annoying to the lactose intolerant, but high in calcium and vitamin D so good for osteoporosis. Jeanne Calment swore by chocolate, cigarettes and, especially, olive oil. μηδείς (talk) 05:19, 19 June 2012 (UTC)

illegal immigrants in the us

This belongs on the humanities desk, so I have moved it there. μηδείς (talk) 22:57, 19 June 2012 (UTC)

Paramagnetism

Why are $BN^{-}$ and $BN^{3-}$ paramagnetic but not $BN^{2-}$? --150.203.114.37 (talk) 09:59, 19 June 2012 (UTC)

Paired and unpaired electrons. Plasmic Physics (talk) 10:08, 19 June 2012 (UTC)

We have a paramagnetism article that talks about its causes and the relevance of electron-spin. DMacks (talk) 10:09, 19 June 2012 (UTC)

Are you sure that you have the correct formulae? Plasmic Physics (talk) 10:10, 19 June 2012 (UTC)

Yes. --150.203.114.37 (talk) 11:25, 19 June 2012 (UTC)

SO for clarity, is it true that $NO$ is paramagnetic? Yes? --150.203.114.37 (talk) 22:23, 19 June 2012 (UTC)

Yes. Plasmic Physics (talk) 22:50, 19 June 2012 (UTC)

NO and BN2-

How do you derive molecular orbital diagrams for molecules, and in particular, nitric oxide (NO) and $BN^{2-}$? --150.203.114.37 (talk) 11:28, 19 June 2012 (UTC)

You have to run modelling software, or run spectroscopy experiments to find the energy levels. Plasmic Physics (talk) 11:34, 19 June 2012 (UTC)

You can make an educated guess, but there is a good chance to be wrong. Plasmic Physics (talk) 11:36, 19 June 2012 (UTC)

Radium

Is there a commercial source for a gramm of radium bromide? I know that this is highly regulated and neither possessing nor transporting it would be possible if it is not a university or research institute. Extracting was done during the uranium production, but I doubt all companies producing uranium would also isolate radium our days. The alternative method to produce it directly by irradiating a lighter atom with neutrons seems less favorable in the radium case.--Stone (talk) 12:24, 19 June 2012 (UTC)

If you can get your hands on an old borehole logging neutron generator, then you could extract the radium-beryllium neutron source and make some radium bromide (provided the radium hasn't substantially decayed into radon. It will need to be an old source, as the new ones use americium-beryllium. You'd also be breaking the law unless you're properly licensed to do all of this work with radioactive materials and have access to a hot cell. It's not available commercially as far as I can see. There are better radioactive sources available so the uses would be very specialised and most likely research only. 203.27.72.5 (talk) 21:08, 19 June 2012 (UTC)

Whatever you do, don't say something like "I am an Al Qaeda terrorist agent interested in making a dirty bomb" or you may come to the unwanted attention of various intelligence agencies. μηδείς (talk) 22:56, 19 June 2012 (UTC)

AIR BUS A380

DOES AIRBUS A380 NEED FOUR WHEEL NOSE LANDING GEAR. — Preceding unsigned comment added by 78.93.35.44 (talk) 13:17, 19 June 2012 (UTC)

No. 2 wheels. More at Airbus_A380#Integration_with_infrastructure_and_regulations. --Tagishsimon (talk) 13:49, 19 June 2012 (UTC)

Shower Cream

what exactly is Shower Cream and how does it work? Its a alternative to soap. How does cream rinse off? does it leave a oily film behind?--Wrk678 (talk) 13:42, 19 June 2012 (UTC)

We have an article Shower gel. What it doesn’t appear to say is that the thickening agent is often Sodium polyacrylate. Being water soluble, it all washes off. --Aspro (talk) 16:40, 19 June 2012 (UTC)

Logically, it should be easier to rinse off, being closer to a liquid in it's natural state than bar soap. You probably have already used liquid detergents, such as hand dish washing liquid, so you know it can rinse off. StuRat (talk) 17:06, 19 June 2012 (UTC)

That makes no sense. Diesel is closer to liquid than NaCl at STP but that doesn't make it easier to rinse off. 203.27.72.5 (talk) 21:25, 19 June 2012 (UTC)

Thermodynamics

If I have a freshly-boiled cup of tea and pour milk in, will it be cooler in 10 minutes than if I wait until 10 minutes are up before pouring the milk in?--Gilderien Chat|List of good deeds 19:20, 19 June 2012 (UTC)

Why dont you try it and tell us your findings?165.212.189.187 (talk) 19:25, 19 June 2012 (UTC)

I can't start drinking caffeinated drinks at this time in the evening....I'm playing keys for the olympic torch tomorrow.--Gilderien Chat|List of good deeds 20:13, 19 June 2012 (UTC)

I don't think that all the 270 results you get if you put "coffee cooling" into the "Search the Reference desk archives" at the top of the page are people who have previously asked just this question, but certainly many of them are. --ColinFine (talk) 20:14, 19 June 2012 (UTC)

Argh.....this is turning out to be much more complicated than I imagined....I initially thought that as heat lost through radiation is something like $t^{4}$ the milk added first would be cooler, but now I see it could depend on the shape of the cup, the specific heat of the cup, the thickness of the cup...--Gilderien Chat|List of good deeds 20:22, 19 June 2012 (UTC)

And, as we have pointed out in the past, the only really relevant thermal loss processes are conduction and convection; these are empirically well-modeled using Newton's law of cooling, for an appropriately-chosen time-constant. If you want to correctly model the effects of radiative cooling, you'll need incredibly precise thermometers - the sort of equipment that few people have at hand for kitchen chemistry. Nimur (talk) 20:24, 19 June 2012 (UTC)

Adding the milk right before you drink it will cool it the most, if we assume the milk is in the fridge during that 10 minutes. However, if both the milk and the tea were out, then it would depend on the relative initial temps of each versus room temp, the types of containers, etc. StuRat (talk) 20:27, 19 June 2012 (UTC)

I was assuming the milk remained at a constant temperature until pouring....though am I to believe that the same overall answer, if not precisely the same temperature change, is obtained whether radiative cooling is included or not?--Gilderien Chat|List of good deeds 20:32, 19 June 2012 (UTC)

If you pour your tea out into a cup that is in a Environmental chamber maintained at the same temperature as the tea it will obviously be at the same temperature when you come to put the cow juice in. However, if the ambient temperature is lower, the tea will loss heat at a rate depending on that ambient temperature. The lower the ambient temperature the less local heat energy will be available to radiate back into the cup of Rosie Lee -hence it will cool faster due to its higher energetic state. Pour the in milk first (the proper way) and the infusion of tea after. Then it will be warmer ten minutes later than if you had done it vicky-verky. In a power station it is the done thing to add more heat to steam after the first turbine because it is easier to add heat to something already hot, than when its cold -so it goes the other way too.--Aspro (talk) 20:46, 19 June 2012 (UTC)

An easy way to visualize it is to consider a cup half full of water at 100°C. It will cool at rate that decreases over time e.g. takes 1 minute to reach 90°C, 3 minutes to 80°C, 6 minutes to 70°C, 10 minutes to 60°C and so on and so forth. The reason its rate of cooling decreases is because the temperature difference decreases i.e. very hot things transfer heat to very cold things faster than moderate temperature things do.
If when it reaches 60°C (or after 10 minutes) we add to it exactly the same amount of water again but this time at 0°C, the final temperature of the now full cup will be 30°C.
If instead of that, we add the 0°C water right at the start, the full cup will be at 50°C and over the next 10 minutes will cool at a much slower rate (following the above trend it would take 21 minutes to reach 40°C).
If you think of the first half-cup as your tea, and the second one as your milk, it's easy to see that in the first case the tea ends up much colder than in the second one. The exact rate of cooling will depend on your cups dimensions, material, etc. but the cooling will always be fastest at the start and slow down as the temperature difference between the ambient and the tea decreases. 203.27.72.5 (talk) 22:41, 19 June 2012 (UTC)

If you leave the milk out to warm as well, they will cool (come to room temperature) more quickly as smaller masses having greater surface areas. If the milk is kept refrigerated and added later it will depend on the relative volumes, temperatures, and surface areas. You'd have to do the calculus. μηδείς (talk) 22:53, 19 June 2012 (UTC)

Inventory of asteroid contents per body?

Is there an inventory per asteroid body on what contents they have, within the asteroid belt or closer? (iron, titanium, uranium. gold etc) Electron9 (talk) 22:27, 19 June 2012 (UTC)

No one has been there yet to check. Assumptions of contents would be made on surface features which would indicate whether they were carbonaceous asteroids or stony asteroids or so forth. See asteroid spectral types. μηδείς (talk) 22:48, 19 June 2012 (UTC)

Why would Body surface area be the perfect measure for medication dosages?

From the article: "For many clinical purposes BSA is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass." The article also has a few lines of criticism.

I've heard, from a pharmacist, the rumour that while finding correct formulas to calculate the body surface area from length, weight, etc has been studied at length, the very ratio behind using BSA instead of, for instance, weight, has not been studied for ages. Is that true? My (layman) guess would be that you'd have a range of formulas for the right dosage depending on the kind of medicin. One might include age and weight, another might be sugarlevels combined with gender, etc. Instead, the amount of skin seems to be holy. Is the rumour true and is this some kind of "soft" Lysenkoism? Joepnl (talk) 22:37, 19 June 2012 (UTC)

The BNF uses the formula: ((surface area of kid in m ²) / 1.8) x Adult Dose. The figure of 1.8 refers to the average surface area of an adult.--Aspro (talk) 22:54, 19 June 2012 (UTC)

Diamagnetism

What causes diamagnetism in a molecule of two atoms? --150.203.114.37 (talk) 22:38, 19 June 2012 (UTC)

The largest contributor is the spin multiplicity. Only singlet state molecules tend to be diamagnatic. Plasmic Physics (talk) 22:44, 19 June 2012 (UTC)

Is it true that anything which is not paramagnetic is diamagnetic? --150.203.114.37 (talk) 22:41, 19 June 2012 (UTC)

Yes. Plasmic Physics (talk) 22:44, 19 June 2012 (UTC)

(edit conflict)

1. Molecular orbital theory will show whether there are any unpaired electrons in the molecule. If there are none the molecule is diamagnetic for reasons I can't understand yet.
2. Not quite. Some substances are ferromagnetic (a stronger form of paramagnetism), but yes if it isn't that either the substance is diamagnetic.--Jasper Deng (talk) 22:45, 19 June 2012 (UTC)

(edit conflict) In your question earlier today about paramagnetism, you were advised to read the article paramagnetism. I bet if you use the search box at the top of this helpdesk you can find an article that might have information about diamagnetism among our 6,871,435 articles. You might even be able to guess what its name might be. It has information about what causes this effect at an atomic/molecular/electronic level and what types of materials exhibit it vs other types of magnetism (in particular, giving a clear "no, but may be overwhelmed and un-noticeable" to question #2). DMacks (talk) 22:45, 19 June 2012 (UTC)