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May 23

Diversity of sexuality #2

I feel bad for reposting this question, but even though the original discussion had a few high-quality answers, it has gone way off track. I think this was because my question wasn't sufficiently clear, so let me clarify:

"Do other animals have unusual sexual interests? Are there chimps, for example, who enjoy sadism, necrophilia, pedophilia, or foot fetishes (assuming these aren't typical amongst the species)?" I'm only interested in objective descriptions of observable behavior, not in any moral judgements made by either humans or animals.

Note that I carefully avoided using any terms that imply a normative judgement. I used "unusual" instead of deviant, unnatural, or abhorrent because unusual is a positive statement, whereas the others imply a moral judgement I refuse to make. Also, the only reason I omitted homosexuality from my list is because I already know many animals are homosexual. It isn't because homosexuality is not unusual (it obviously is), nor is it related to any opinions I have about sexual behavior. If possible, I'd prefer the answers to similarly refrain from all normative judgement. Thanks in advance. --140.180.5.169 (talk) 04:17, 23 May 2012 (UTC)

Because you included the word "enjoy", an answer must require some judgement, normative or whatever. For instance, dogs humping legs are commonly seen. I would assume this is NOT because they have a leg fetish - its more likely they are feeling horny, but can't find a female of compatible size. But how are we to know? Maybe dogs enjoy humping legs, or maybe its frustrating for them. Its common for dogs to lick their genitals - because they can. Do they enjoy it as masturbation? It certainly seems so. Male spiders tend to get eaten after they've done the deed. Is this part of sex for the female? Who knows, put probably not. Its probably just a case of the sexual stimulation of the males's courtship dance stopped, and the female's brain now recognises food. Ratbone120.145.20.154 (talk) 05:43, 23 May 2012 (UTC)

You're still assuming animals possess language and culture, "sadism, necrophilia, pedophilia, or foot fetishes" are specific human cultural features in English. Your comment above regarding neuronal analysis of behaviour is specious, as you can't neuronally analyse human sadism. Do animals injure other animals during coitus: yes. Do animals construct the injury of other animals as part of a psychosexual structure of symbols: no. Do animals engage in coitus with dead things: yes. Do animals construct "death," "permissable sexual activity," "impermissable sexual activity," and the "specific impermissable sexual activity of sex with dead things" as cultural meanings: no. Do animals engage in coitus with sexually immature animals: yes. Do animals construct a social and cultural category of a "child" and construct the impermissable sexual activity of sex with a child: no. Animals do not socially construct "children," and any different behaviour towards juveniles is purely different behaviour towards juveniles. Do animals have foot fetishes: no. Animals do not construct cultural or psychosexual fetish objects, animals do not have fetishes, they have behaviours. Are there stereotyped behavioural examples of animals attempting to copulate with limbs, yes. Do dogs have an interior construction of a socially ideal leg: no. You're persisting in inflicting anthropocentric categories of social, cultural and psychosexual analysis on animal behaviours. Answer me this: Who was dog Hitler? Fifelfoo (talk) 08:23, 23 May 2012 (UTC)

Are you sure this is true? I know that the tendency to anthropomorphism is a much condemned excess; nonetheless, I find it very hard to believe that there is not some literal homology between the bass defending his nest and the farmer with the rock salt shotgun watching over his field, or indeed the elephant seal or the sultan defending their harem. Animal culture exists to some extent, and I'd be more surprised if dogs didn't have some way to agree that some females are particularly attractive. I'll agree, of course, that anthropomorphizing is often dubious and can quickly stray into fantasy, but it is a rich source of plausible hypotheses, and I doubt many of them have actually been disproved conclusively. Wnt (talk) 12:54, 23 May 2012 (UTC)

One of the tests we can briefly create for "culture" is the reversal of behaviour structure in certain circumstances—the festival or jubilee. Sultans allow their harems to be cuckolded for specific reasons, farmers allow members of their religious community to share in their excess. These contradictions don't arise in animal behaviour because animals aren't subject of language. Even when we can credit behavioural dominance over consciousness in human behaviour structures—such as new human males killing their female's old juveniles and similar animal behaviour structures—the animals never experience the human cultural elements: marriage, cuckoldry, bastardy, infanticide, murder, the cycle of the Titans, etc. So while we can draw behavioural metaphors in some circumstances (and I'd limit them far more than your examples), even when the behaviours are demonstrably pre-conscious and not related to the sub-conscious, the human experience of these behaviours is radically different to animal experience. Cats ejaculate, I ejaculate, cats never stare at the ceiling wondering if their ejaculate was sufficiently pleasing for their partner. Fifelfoo (talk) 23:31, 23 May 2012 (UTC)

Something resembling a source for this discussion can be found at [1]; on thinking in general it raises the example that scrub-jays which cache food when observed will re-cache it when unobserved, reflecting their awareness that the other bird will consider taking it. Maybe it would be interesting to have three scrub-jays, two conditioned to cache red balls for a food reward, a third conditioned to cache blue balls, each marked in some way for recognizability within some vast experimental enclosure with limited domains of visibility. Would the blue-caching scrub-jays recognize that the red-ball cacher is no threat to them, while taking precautions against one another? Or what if they had a chance to observe that one scrub-jay were conditioned, or had a natural propensity, to steal others' caches, and the other didn't? Would they recognize the bird by personality? Wnt (talk) 20:52, 24 May 2012 (UTC)

One of the problems with the scrub-jay experiment you outline, is that it would demonstrate that the blue caching scrub-jay carries an interior model of the thought process of the red caching scrub-jay, but it wouldn't demonstrate an internal symbol system sufficiently complex to get that contradictory kind of thought process that plagues our days. I like the discussion in the Handbook of Jealousy, that would be really interesting to conduct vasopressin antagonist studies on humans during sex, and then prompt them with threats and ask them about their interiority. Fifelfoo (talk) 23:25, 24 May 2012 (UTC)

The 2003 Ignobel Prize for Biology was won by Kees Moeliker for his investigations into Homosexual necrophilia in the mallard duck [2]. You may be interested in the rest of the Animal sexual behaviour article as well. LukeSurl ^{t c} 09:46, 23 May 2012 (UTC)

The fundamental error in the question is the term "unusual". It amounts to applying human standards to non-humans. Morality is a human concept. Animals don't have "morality". They do what they do. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:05, 23 May 2012 (UTC)

Meh. I've known pets with a greater sense of morality, as in knowing right from wrong, than many humans. --76.182.93.85 (talk) 12:13, 23 May 2012 (UTC)

I think it's fairly obvious what the OP is asking for [i.e. interesting animal sex facts]. I'm not sure what purpose scrutinising the exact wording of his inquiry serves. LukeSurl ^{t c} 12:33, 23 May 2012 (UTC)

It serves for clarification. Your assumption may be correct, but that's not entirely clear from the question. — The Hand That Feeds You:^Bite 12:57, 23 May 2012 (UTC)

The issue is that we cannot be certain of the motive behind the act. As an example, there was a humorous meme image that involved a mouse having sex with a female who was dead in a mousetrap. There's no way of knowing if the male was sexually attracted because she was dead, or if he was simply taking advantage of the fact that the female didn't rebuff him (not realizing she was dead). There's no way of knowing if this was necrophilia in the psychological sense, or if it was just sex with a corpse because it was available. — The Hand That Feeds You:^Bite 13:14, 23 May 2012 (UTC)

Ha, if it were that simple and not entirely relevant, because even with people its not likely to be an either/or motivation, for its likely that a very high level of availability, such as being an ugly frustrated son of an undertaker, leads to the necrophilia of ending up with "unusual" macabre acts of loving the dead, so they are not behaving any better than some poor rodents. --76.182.93.85 (talk) 13:35, 23 May 2012 (UTC)

The other thing being ignored here is that no non-Human animal shows signs of true metacognition and theory of mind. That is what Fifelfoo is getting at above. Do animals display sexual behaviors which, if humans did them, other humans may view as deviant? Absolutely. I have seen animals fuck anything. But to assign human values to those behaviors is meaningless, as those human values require that the animals are capable of sapience or self-actualization, or metacognition, or theory of mind, which no evidence has been shown that they can or do. A dog doesn't spend a lot of time worrying about if his sexual partner enjoyed the experience, a dog doesn't have the ability to project its own values on the minds of others, or even to think about its own values. It gets horny, it fucks something. It will fuck the nearest female dog in heat, if availible. But it doesn't spend a whole lot of effort considering the implications of its sexual act in culturally acceptable ways. It just doesn't. The OP has been provided with ample evidence of sexual behaviors which, when compared to human sexual standards, would be deviant in humans. It doesn't mean anything that animals display these behaviors, however, because animals don't have the expectations within themselves over what constitutes acceptable sexual boundaries. --Jayron32 17:40, 23 May 2012 (UTC)

I think there is evidence that some animals consider how others will view their sexual activity. In many cases a secret sexual encounter occurs, when making it known would have negative consequences. StuRat (talk) 17:54, 23 May 2012 (UTC)

Avoidance of consequences is not a sign of metacognition. If I hit my dog on the nose with newspaper every time he pees on the carpet, he stops peeing on the carpet. It doesn't mean he has an understanding of socially correct bathroom usage. He just doesn't like getting hit with a newspaper. --Jayron32 18:08, 23 May 2012 (UTC)

Certainly avoidance of consequences are apart of metacognition, because operant conditioning is a major part of our own human social conditioning. --76.182.93.85 (talk) 18:17, 23 May 2012 (UTC)

It isn't a part of metacognition though. You don't have to be able to understand your own internal thought processes to avoid consequences. You just do it without thinking about it. The important parts of metacognition is being able to think about your own thoughts, and think about the thoughts of others. Dogs can't do this. --Jayron32 19:33, 23 May 2012 (UTC)

Saying "Dogs can't do this." is simply meaningless chopping off the head of the dog (which are quite intelligent) to make people seem more cognitive. Instead of advocating on their terms, whatever that may be, we get unfounded assertions. (and I am the 76. IP, because wasn't logged in earlier) --Modocc (talk) 19:39, 23 May 2012 (UTC)

I suppose you have evidence that dogs can do it then. We don't just accept a random assertion without evidence, or I can claim anything I want and you need to prove me wrong. I can assert that a dog wrote all of the Homeric epics, and you haven't proven that it didn't. On the contrary, we have no evidence that any form of life other than humans is capable of metacognitive thought on anything close to what humans can do. There just isn't. There are occasional studies that show maybe, kinda, if you look at it in a certain way, that an animal displays a behavior that with enough wishful thinking and hope that it shows metacognitive thought. But as capable as dogs are of doing very complex things, there is simply no evidence that they have internal monologues or have a theory of mind or anything like that. --Jayron32 20:27, 23 May 2012 (UTC)

I am not the one claiming they can't have cognitive thoughts (which BTW, contrary to what one might conclude from scripted forms of communications do not require internal symbolic monologues) that associate actors with emotions, actions and potential actions and emotions (their own as with well as with others), as well as various strategies involving those things. To the contrary, both dogs and people show a wide range of variation in their individual abilities to socialize and/or to problem solve. --Modocc (talk) 20:42, 23 May 2012 (UTC)

I have never made that claim either. You should read what I wrote, and learn the definitions of words before you disagree with someone over something they haven't said. --Jayron32 20:59, 23 May 2012 (UTC)

"The important parts of metacognition is being able to think about your own thoughts, and think about the thoughts of others." which is the cognition of thoughts, which might be as simple as whether or not when I pick up the car keys we might be going for a car ride (Teachy runs for the door in anticipation). Call this metacognition or simply a cognition or whatever you like, its absurd to set up a model of thought or a theory of mind and use these as litmus test to make unfounded claims. Its a typical strawman fallacy. --Modocc (talk) 21:19, 23 May 2012 (UTC)

It isn't a strawman fallacy. There's a difference between reacting to a stimuli and understanding what another is thinking. Your dog knows that when you pick up the keys, you're going for a car ride. He doesn't analyze what you are thinking about. He's responding to training. --Jayron32 01:06, 24 May 2012 (UTC)

How do you know my dog knows? What does he know or thinking about? Teachy also does her best to convince me its a great idea. She is uncertain because I don't always leave or take her with me. Of course I figured you would jump to the training bit as if people never take their own such experiences in to account. Models should fit facts, because facts do not fit models unless the facts are true. Its not hard to believe anything if you base conclusions on poorly conceived models of reality which is what strawmen generally are. --Modocc (talk) 01:13, 24 May 2012 (UTC)

When you say "How do you know my dog knows? What does he know or thinking about?", that is my whole point. You can't make positive assertions without evidence. You can't declare that your dog has some ability simply because no one has yet found evidence that she does not. Can you prove that she isn't busy translating Shakespeare into idiomatic Quebecois French in her mind or solving Maxwell's equations for fun as an intellectual exercise? No, you can't. But just because you can't prove she's not doing those things doesn't mean you should demand that the world accepts that she is doing them. That's the whole point: there is no way to access the internal thought processes of a dog (or any similar animal), and so to make outrageous claims about their abilities based on the fact that you cannot prove they don't have them is just patently rediculous. --Jayron32 19:44, 24 May 2012 (UTC)

Of course she does not have poetic thoughts like a person might. Your position set the bar very low though with the statement that a metacognition was "being able to think about your own thoughts, and think about the thoughts of others"! Surely Teachy is thinking about a car ride, which are her own "thoughts" about such an event. From what you have written thus far, you appear to have made the claim that this dog has not the complexity of thought as to be cognitive of her own thoughts regarding the idea of such future activity based on her memory. In any case, I am not even asserting that she does and can think with metacognition, only that such evidence tends to refute your unfounded position that she cannot. --Modocc (talk) 04:26, 25 May 2012 (UTC)

I agree that dogs can't, but there are more intelligent animals around. For other evidence of their intelligence, there's the mirror test, where the most intelligent animals realize they are seeing themselves and are fascinated by their reflections. StuRat (talk) 20:10, 23 May 2012 (UTC)

Such tests should be evaluated with caution. In other words, they can rule in or out certain recognition tasks, but not all related tasks. --Modocc (talk) 20:26, 23 May 2012 (UTC)

I guess we can only wait for #3, I feel bad for reposting this question, but even though the original discussion had a few high-quality answers, it has gone way off track. . Anyway bonobos seem to have few taboos. Joepnl (talk) 21:19, 23 May 2012 (UTC)

Diversity of sexuality (sexual behaviour) #3

Please list ways in which animals have sex which appear weird to humans (take as your baseline for "human" an Australian wikipedian in his 30s who wants the IP to get their weird animal sexual behaviour list; or if other definitions of "human" make for interesting weirdness, feel free to go with those). Citations to papers preferred! Also pictures of slugs having sex from trees. Fifelfoo (talk) 23:44, 23 May 2012 (UTC)

Well the article linked above, Animal sexual behaviour, and I bet you can find the slug pictures for yourself if you look at the Commons, they are even in a tree and on a wall. But all in all these are one of the weirdest around. CambridgeBayWeather (talk) 07:42, 24 May 2012 (UTC)

Dogs hump legs. HiLo48 (talk) 08:07, 24 May 2012 (UTC)

You're going to have to confine yourself to mammals to keep the list manageable. If you're going by weird arthropod mating habits, you could write an entire book on it. In fact, that book has been written more than once. Google "sex on six legs" for I think the most recent one. Someguy1221 (talk) 09:20, 24 May 2012 (UTC)

One of my personal favourites - in seahorses the male becomes pregnant and carries the developing eggs through gestation until birth. Gandalf61 (talk) 09:48, 24 May 2012 (UTC)

Could plants extract metabolic energy from wind?

In present day societies it seems like wind plants are being built in preference to solar plants as a source of energy. Yet thinking about plants... we think of solar power, never wind power. Of course there is wind dispersal for seed dispersal and anemophily; I'm thinking more though of plants extracting metabolic (chemical) energy from the wind.

It occurs to me that if I were to design plants to capture wind power, I would construct many elements that would flap constantly in the breeze, i.e. leaves, connected to bundles of closed fluid tubes such as xylem or maybe phloem. As the bundles would periodically be contracted and expanded by the wind, pressure differentials should exist at cell membranes. If fluid were permitted to leak through freely under pressure in one direction, but forced through a semipermeable membrane when passing in the other, a solute could build up on one side of the membrane, creating a chemical potential from which energy could be extracted.

I suppose a simpler but still useful mechanism would be simply if the flapping leaf helped pump fluid to the top of the plant, a purely mechanical process that nonetheless would spare some sort of osmotic or evaporative pump at the root or leaf (depending on the vessel type).

Is there any known method for rooted plants to harvest wind energy? Wnt (talk) 12:40, 23 May 2012 (UTC)

Wind causes damage to the plant tissue similar to the way we damage our muscles when we workout. This damage in turn causes the plant to repair the area and it becomes stronger, thus enabling it to withstand a greater load in the future. So it does gain potential energy.165.212.189.187 (talk) 16:30, 23 May 2012 (UTC)

But that energy to repair the leaves the plant derives not from wind, but from photosynthesis (and is thus solar power). - Lindert (talk) 16:36, 23 May 2012 (UTC)

But the catalyst is the wind, otherwise the plant would make itself stronger initially, which it doesn't.165.212.189.187 (talk) 20:23, 23 May 2012 (UTC)

Lindert is right. that's not what potential energy means 165.212.189.187. LukeSurl ^{t c} 21:07, 23 May 2012 (UTC)

then what is the plants ability to resist stronger winds due to it's stronger stem, Or support a greater load?68.83.98.40 (talk) 04:40, 24 May 2012 (UTC)

The point is that a catalyst does not supply any of the required energy. It's not the wind that makes the stem stronger, but the plants metabolism reacting to the wind, just like floods do not build dykes, but people build them in response to floods. Also, as LukeSurl pointed out, the ability to resist something is not potential energy. For example, a diamond has a high resistance to breaking, because of its strong chemical bonds. However, it has very little potential energy, i.e. very little energy could be extracted from the diamond, because it is in a very low energy state. - Lindert (talk) 09:36, 24 May 2012 (UTC)

Plants metabolise gasses from the air with water, light, and minerals from the soil. Rotating movement is only possible in free moving organisms like a tumbleweed or a manis. The closest thing to a true wheel in organisms is the flagellum, and that could not power a toy battery. You couldn't power an LED light off it. ~ R.T.G 20:57, 23 May 2012 (UTC)

Aye. While I suppose a plant generating energy from wind is theoretically possible, it seems unlikely that the efficiencies involved would make the evolving of the ability to harness it viable. LukeSurl ^{t c} 21:07, 23 May 2012 (UTC)

Short answer is no; there are no known methods for coverting mechanical energy to metabolic energy in plants (or any other organisms). Only light (as in photoautotrophes) and chemical energy (as in chemotrophes) are known to be used to get metabolic energy. Ionizing radiation may also be used in some way by some fungi. 203.27.72.5 (talk) 07:29, 25 May 2012 (UTC)

Science Project

I am doing a science project and I already browsed all around the web for ideas. Here's the criteria:

• It has to be something applicable in the modern household
• You need to have a investigative queation eg. What will happen...?
• We would prefer a exciting experiment such as a chemical reaction.

The main problem I have is to get something exciting and extraordinary which is also applicable in the household. Can someone please help me? I would appreciate if you could tell me of a project you did/see in the past or perhaps give me a internet link.41.125.84.204 (talk) 15:27, 23 May 2012 (UTC)

A few thoughts: Firstly, I'm sure you've read the top of the page, but we won't do your homework for you. A large part of the objective of this exercise is likely to be getting you to be creative and understand the process behind how scientists go about setting themselves research projects, and so on. Therefore, just asking us to provide you with a topic for your project is defeating the object. A better idea might be if you could tell us some of the ideas you've had so far - don't worry how bad you think they are, or how unachievable they might be, we can work on that - and we can then help you to find ways in which to put them into practice. Secondly, if you could tell us what level this project would be at (e.g. K-12 Twelfth grade, GCSE, degree level) then we will have a better feeling for what sort of ideas we can pitch you. Hope this helps. - Cucumber Mike (talk) 15:42, 23 May 2012 (UTC)

How about an experiment on electricity usages of various household devices. Most people have a visible electrical meter outside of your house. DO things like measure the amount of electrical energy your house uses in the aveage day, and then see how that changes when you, say, don't run the air conditioning all day, or unplug every electric device (to see the effect of Vampire power) and things like that. --Jayron32 16:50, 23 May 2012 (UTC)

How about a comparison study between a number of different brands of a particular type of household product? Setting up a fair test to see which does the job best would demonstrate a lot about the methods of scientific investigation. LukeSurl ^{t c} 15:54, 23 May 2012 (UTC)

Somebody just asked the question here: "Which is most efficient, using a stove or microwave to boil water for coffee ?" [3]. You could do the experiment yourself, reading the home electricity meter to determine the difference between having each appliance on and off, and then multiply that electricity usage rate by the time it takes to heat the water to boiling from a fixed starting temp. Do the experiment several times, and average out the results. You can then multiply by your electricity cost to determine the cost difference. StuRat (talk) 17:14, 23 May 2012 (UTC)

You could compare a cleaning fluid you buy in the shop (we have Flash in the UK) with a more natural product such as lemon juice, vinegar, bicarbonate of soda, or a mixture of them, to see which is more effective at removing dirt. --TammyMoet (talk) 18:18, 23 May 2012 (UTC)

Mixing household chemicals may lead to dangerous reactions. Find out which chemicals will react with each other and what the reaction products are. Do they generate heat, flammable gas, poisonous gas, or do you end up with salt water? You better research and ask advice before (or instead of) doing any actual mixing. Some common chemicals: bleach (chlorine), acetone, hydrochloric acid, drain cleaner, hydrogen peroxide (contact lens solution), sodium bicarbonate, vinegar, ... Combinations of them create heat, CO2, poisonous Cl fumes, chloroform, table salt, oxygen, steam, or a dangerously unstable explosive... Ssscienccce (talk) 05:06, 25 May 2012 (UTC)

Where's the rule about how high model rockets can go in the US

I know you all are hyper-vigilant about saying yourselves what laws do and do not say. I just want to be pointed to the people who do say what the altitude limit is for model rockets in the US before you have to go get some paperwork from the FAA or whatever other agencies would be offended by a high-flying tube. I can't find that nugget of knowledge on their site. 20.137.18.53 (talk) 16:46, 23 May 2012 (UTC)

I can give you an upper limit in that in the US everything about flight level 180 is controlled airspace. You might also find it interesting to read Airspace class (United States). I do not know what the regs about model rockets in particular are though. Egg Centric 16:51, 23 May 2012 (UTC)

I found this page on the National Association of Rocketry website. Roger (talk) 16:58, 23 May 2012 (UTC)

In short, for small rockets (I see they've raised the weight limit from 16 ounces to 53 ounces), there's no height limit; the only limitation is "how high can you send it on 125 grams of propellant?". --Carnildo (talk) 01:44, 24 May 2012 (UTC)

Trebuchet design.

I know that Trebuchets from medieval times had a simple pin hinge - and a beam with a gigantic weight on one end and a sling for the missile on the other. I also know that modern trebuchet enthusiasts (eg at Pumpkin chunking events) have improved the design by replacing the pin hinge with an axle with wheels on the end that run along a horizontal track (a "floating arm trebuchet") - which is better because the fulcrum can now move such that the weight can fall in a straight, vertical line without absorbing energy by accelerating horizontally as it does in the classical design where it falls through a roughly 90 degree arc. Also, this large and dangerous weight doesn't end up swinging violently back and forth.

However, it seems to me that a simpler design would be to have two pin hinges and an additional linkage to do the same basic thing (the red component in the image at right). Is there any obvious (or non-obvious) reason why the floating arm version is better than mine? Is there any precedent for trebuchets built this way? I don't see any examples in our Trebuchet article that work like this. SteveBaker (talk) 16:53, 23 May 2012 (UTC)

There is another option. I saw a documentary where they tried to recreate a medieval trebuchet, and they concluded that the entire device was likely built on wheels, both to be able to move it into position, but also to allow the weight to fall more vertically (as the device moved under it) and to absorb the "recoil", which otherwise might destroy the device. StuRat (talk) 17:05, 23 May 2012 (UTC)

(ec)Sorry if this is off-topic, but I'm slightly confused after looking at our 'Trebuchet' article. I thought the simple, efficient, doesn't-shake-to-pieces standard design for a large trebuchet was to mount the whole thing on wheels, such that it moves backwards and forwards as the weight swings. I don't see any trebuchets like that in our article, but I thought recreations that omitted the wheels tended to shake to pieces when used with realistic loads. 109.155.32.126 (talk) 17:08, 23 May 2012 (UTC)

This one: File:Punkin-Chunkin-2008-Trebuchet.JPG has wheels - presumably for that reason. SteveBaker (talk) 19:35, 23 May 2012 (UTC)

The reason it will not work as well is because the design does not in fact allow the weight to fall in a straight line. In the situation where the weight has begun to fall, you can imagine that the red component is at an angle compared to a vertical line. The force the red linkage exerts on the fixed chassis of the trebuchet must necessarily be parallel to this linkage, which means there is a horizontal component to that force. Newtons third law dictates that, because the moving components exert a horizontal force on the fixed trebuchet, an equal and opposite force is exerted by the fixed trebuchet on the moving components. Therefore, the weight will accelerate to the right (i.e. in the first part of the falling motion), though not as much as it would in the simpler design. I hope this makes sense. - Lindert (talk) 18:27, 23 May 2012 (UTC)

Yes, I understand that - the issue is essentially the same for the floating arm trebuchets. The actual implementation of both this version and the floating arm trebuchets have some kind of a fixed vertical guide rail to force the weight to fall vertically. I didn't want to clutter the diagram too much so I left that out - I guess it's kinda important! SteveBaker (talk) 19:35, 23 May 2012 (UTC)

What would be the problem with a more conventional crank arrangement? Position the weight directly below the main pivot, and connect it to the short end of the arm using a rod with a hinge in the middle. Tevildo (talk) 20:14, 23 May 2012 (UTC)

Ok, thanks for clarifying. In that case I see no reason why your version could not work just as well as the floating arm design. To be sure, you might try to do a physics simulation. There may be implementational difficulties, but I wouldn't know about that. As for a precedent, not that I am aware of, but considering how many people have experimented with altered designs, I'd say there's a pretty high chance someone has tried it. - Lindert (talk) 20:29, 23 May 2012 (UTC)

Looking at the pics of the trebuchet article, I'm thinking: Yours has to be taller (to compensate for the length of the extra pieces) and wider (hinges at both sides, with the arm in the middle, extra piece on each side, the other ends on second axle) putting more force on the axle, the "inner" axle has to be trimmed as much as possible since it must fit between the two supports, and the bigger that distance, the more stress in the other axle. Ssscienccce (talk) 05:45, 25 May 2012 (UTC)

Odd smell after a hailstorm

OK. Question here for the meteorologists/atmospheric scientists/amateur bullshitters out there. After a recent hailstorm, after most of the hail had melted, there was a very distinct smell in the air. It smelled like pine, maybe terpentine or pinetar. That kind of smell. It wasn't local to my house; I ran an errand a mile from my house, and the distinctive smell was there too. What about the hailstorm could have caused this? --Jayron32 21:02, 23 May 2012 (UTC)

Are you sure it wasn't ozone ? This is common during thunderstorms. StuRat (talk) 21:09, 23 May 2012 (UTC)

No, I recognize ozone, this was definately not that. I have smelled ozone after thunderstorms and in other contexts. This was definately piney, like terpentine. --Jayron32 21:16, 23 May 2012 (UTC)

Question: Before the hail was the weather dry. If so you may be referring to Petrichor.--Aspro (talk) 21:17, 23 May 2012 (UTC)

Another possibility is that there was an updraft (frequently associated with hail), which sucked up some kind of oil off the ground. For example, some roads are treated by spraying oil on them. StuRat (talk) 21:30, 23 May 2012 (UTC)

Stu may be onto something. It wasn't petrichor: I've smelled rain before, believe it or not. This wasn't it. But I like Stu's idea: Perhaps something like a distant forest fire introduced an aerosol of piney smelling stuff high into the clouds, which provided nucleation for the hailstones, which then returned to earth and released that smell. Anyone out there know if this has been demosntrated to have happened before. --Jayron32 21:35, 23 May 2012 (UTC)

Here's the science part ... so consecrate: Petrichor contains Terpenoids thus can smell like terpentine re: [4].The exact small depends on local soil conditions. And as you stated 'it wasn't rain' but hail so the soil may never have got wet enough to release the 'rain smell' . We get this phenomena in Europe sometimes. --Aspro (talk) 21:41, 23 May 2012 (UTC)

Hailstones form by continuous freezing, but can form so fast that air bubbles are trapped within the structure (that's when you get "cloudy" ice); as it melts, it's not inconceivable that a large amount of organic aerosols were caught up in the updraft, frozen in the hail, then released by the melting. However, I find Aspro's explanation to be much more likely.-RunningOnBrains^(talk) 22:57, 23 May 2012 (UTC)

Actually, I am more inclined to think that it was in the hailstones themselves. A friend of a friend (someone who I don't know) told her, independent of my talking about it, about the strange piney smell following the same hailstorm, some 20 miles from where I live. It seems very likely that there was something in the ice. The soil never smells like terpentine when it rains at other times, and it rains often enough you'd think I'd notice. --Jayron32 01:00, 24 May 2012 (UTC)

My guess is that the hail banged up a lot of tender, new growth on evergreen trees, and then the variable winds of the thunderstorm (either the up- or downdraft or straight-lines) mixed the pine scent throughout the air. If I had to guess, I'd say the hail was pretty small, not enough to bring down limbs, but fairly uniform in coverage. Much less inspiringly, it could have simply been the storm blowing the smell of a logging operation or something downwind, and the hail had nothing to do with it. Juliancolton (talk) 01:41, 24 May 2012 (UTC)

FTR, this has been documented before, which confirms my belief that the hail simply dinged up a lot of pine trees, either by stripping bark or crushing new needles.

6/9/2011 1.00 6 W SALISBURY ROWAN NC A FEW WAVES OF BRIEF HAIL FOR ABOUT 5 MINUTES...BUT LARGEST AROUND QUARTER SIZED. ENDED AROUND 525 PM.

STRONG SMELL OF PINE IN THE AIR AFTER STORM. (GSP)" Juliancolton (talk) 01:44, 24 May 2012 (UTC)

So I guess the remaining question is, Jayron, do you live in the vicinity of trees? Because to me this seems like the most likely explanation (and I am kicking myself for not thinking of it; I'm just so used to hailstorms in the Great Plains). -RunningOnBrains^(talk) 03:21, 24 May 2012 (UTC)

That could be it. Interestingly, I live in North Carolina as the above report is from as well. The apex tree is the Carolina Pine, which is the tallest tree around, so it makes a lot of sense that it would get the brunt of the damage from the hailstorm. As you note, the stones were small (pebbles sized, probably slightly larger than a Cheerio) and uniform in their distribution. I think we have our answer. Thanks to everyone for some excellent answers, I think I'm going to go with "slight damage to lots of pine trees" as the answer, especially given that an earlier nearby storm was reported to do exactly that last year. --Jayron32 19:26, 24 May 2012 (UTC)

SELF CHARGING ELECTRICAL CAR

And I have a bunch of lakefront property in north Ontario for sale. CambridgeBayWeather (talk) 07:19, 24 May 2012 (UTC)

I invent the SELF CHARGING ELECTRICAL CAR and I have the same the Wright broter had no one belived it could be done,but is alrady finish. We would be ENERGY INDEPENDENT yes or no? (Please see You tube papas invention,pulling the plug- Home town News) Thank you and god bles America....great cuontry — Preceding unsigned comment added by 74.243.15.232 (talk) 21:32, 23 May 2012 (UTC) Please explain where the energy comes from to charge the car. StuRat (talk) 21:34, 23 May 2012 (UTC) Ah, but can it run on pure Florida orange juice? --Aspro (talk) 21:53, 23 May 2012 (UTC) Cool idea. Orange juice contains lots of energy, though it may not be gasoline... and imagine the publicity of the stunt! But technically very hard! Wnt (talk) 02:33, 24 May 2012 (UTC) I suppose you could, by letting it ferment into alcohol. Of course, OJ is about as expensive as gasoline, and the small amount of alcohol you would get from it would be far more expensive. And, if people started using it to power cars, it would get even more expensive. StuRat (talk) 04:32, 24 May 2012 (UTC) Nonsense. Energy must always be lost in one way or another via friction. There is no way it can be charged without some energy input. I saw nothing relevant on YouTube with those search queries.--Jasper Deng (talk) 22:35, 23 May 2012 (UTC) The video is here. To save time, it shows nothing but a car with a mess of batteries under the hood, and the car driving around over some music playing. There are no interviews with, for example, physicists who have tested it and are sitting in slack-jawed shocked that the last 200 years of science turns out to be all wrong. I suspect it's just chemical power.--Fuhghettaboutit (talk) 22:56, 23 May 2012 (UTC) He's referring to this steaming pile of crap. He claims that his modified car runs on multiple banks of rechargeable batteries, and that when one bank runs low, another bank will simultaneously recharge it and keep the car running. Violations of the laws of physics aside, the "inventor" has thus far refused to let anyone see how the car works, which is a guarantee that he's full of shit. Someguy1221 (talk) 22:55, 23 May 2012 (UTC) I'm especially a fan of his assertion that "In 10 years, gas will cost 10 cents a gallon." Because clearly companies will continue to refine gasoline and sell it at an extreme loss if it is no longer needed. -RunningOnBrains(talk) 23:01, 23 May 2012 (UTC) I figure the guy is recharging the batteries by pedaling a bicycle that is rigged somehow to generate electricity. That would work, although the pedaler would have to get "recharged" frequently due to all the exercise. ←Baseball Bugs What's up, Doc? carrots→ 23:06, 23 May 2012 (UTC) That's not "self charging", though.Jasper Deng (talk) 23:49, 23 May 2012 (UTC) Sure it is. He's doing it himself. :) ←Baseball Bugs What's up, Doc? carrots→ 01:31, 24 May 2012 (UTC) Please, there's not even a question in here. The OP seems to be either a troll or trying to get hits for his youtube video, and you are all obliging. Vespine (talk) 04:25, 24 May 2012 (UTC)

Self charging electric cars are nothing new, they have been used to drive 'around the world' and they are often used for racing. Those cars are designed to run all day long, however, for cars that are subject to normal, less frequent use, designs are a lot more flexible, cheap and easy to implement. It also means you never need to look for a shady tree to park the car underneath, or burn your bum when you come back to the car in hot countries :) Penyulap ☏ 03:08, 26 May 2012 (UTC)

Oestrogen injections for sociopaths

I understand that it's believed that sociopaths lack a part of the brain to do with empathy. Personally I suspect it's unlikely that it's a binary thing, and at least with the majority of sociopaths there'll be a bit of that part lying around. Is it plausible that oestrogen injections could make that part more effective, and make the sociopath more empathetic? Egg Centric 22:41, 23 May 2012 (UTC)

The premise is wrong: there is no serious theory saying that sociopaths lack any brain part. Some people believe that sociopathy is often caused by insensitivity to punishment, which involves a variety of brain systems. I don't see any clear reason why estrogen injections would make a difference, but really the whole topic is a bit of a boggle. Looie496 (talk) 22:51, 23 May 2012 (UTC)

You'd be more likely to succeed with oxytocin, but pull that stunt and I might side with the sociopaths. Wnt (talk) 02:35, 24 May 2012 (UTC)

Maybe that was chief ingredient of Love Potion Number 9. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:32, 24 May 2012 (UTC)

Is the psi function real?

Have there been any followups to this: http://www.nature.com/news/quantum-theorem-shakes-foundations-1.9392 Bubba73 ^{You talkin' to me?} 23:58, 23 May 2012 (UTC)

Did you see the "Related Links" section, and the comments section? Those are the followups. I can't find citations for this paper; and to be perfectly frank, it looks like a mathematical formalization of grammatical ambiguity. It's not surprising that it's on ArXiv instead of a peer-reviewed physics journal. (I see that it did make it into Nature Physics, just a few days ago). Nimur (talk) 00:59, 24 May 2012 (UTC)

I did not read those because they could say anything. Bubba73 ^{You talkin' to me?} 01:57, 24 May 2012 (UTC)

I don't follow it completely, but the result appears to be quite similar to Bell's theorem, which is very well known. Looie496 (talk) 02:01, 24 May 2012 (UTC)

I agree with Nimur that this seems pretty weak, and not likely to convince anyone who wasn't already predisposed to believe in the reality of the wave function. You said that the replies "could say anything"; I'm not sure what you mean by that, but it's more or less true of the paper itself. The barrier to getting published isn't all that high. -- BenRG (talk) 02:21, 24 May 2012 (UTC)

The barrier to getting a positive (or at least interested) mention in Nature, though, one would expect to be higher. --Trovatore (talk) 02:23, 24 May 2012 (UTC)

When I said "people could say anything" it is because the comments seemed like a blog. Papers are subject to peer review, which is a much higher standard than simple blog comments. Bubba73 ^{You talkin' to me?} 02:30, 24 May 2012 (UTC)

Note that ArXiv is not peer-reviewed. Anyone can author a paper there; although it is moderated, that is not necessarily an endorsement of the quality of the material. As far as I can tell this paper has not (yet) been published in a peer-reviewed journal.-RunningOnBrains^(talk) 03:17, 24 May 2012 (UTC)

Bubba, did you read the paper, though? What you linked to is a puff piece about the paper, paid for by the publisher and posted on the publisher's blog. It's not peer reviewed and I doubt the author is bound to journalistic standards of fact checking and unbiased reporting.

Trovatore, the journal is Nature Physics, not Nature. -- BenRG (talk) 04:26, 24 May 2012 (UTC)

The original link is to Nature. That's the comment I was referring to. I haven't looked at any of the "follow-up" links. --Trovatore (talk) 04:32, 24 May 2012 (UTC)

No, I did not read the paper but I did read the abstract. Bubba73 ^{You talkin' to me?} 05:01, 24 May 2012 (UTC)

Bubba, why don't you read the paper and decide for yourself? To the others: in fairness, this paper did get published in a peer-reviewed journal, Nature Physics, which is fairly prestigious. Though it is connected to the "more prestigious" journal Nature, its author information page states that it is "editorially independent, and its editors make their own decisions, independent of the other Nature journals." I have regularly read Nature and its various subject area journals, and in my mind, there's a clear difference in the significance between the journals. Nature publishes "the world's best science," and though the claim is made that "Nature Physics publishes papers of the highest quality and significance in all areas of physics," it is my opinion that the general importance of such papers is magnitudes lower than, say, the current issue of Nature's feature on Gran Sasso - a feature that is arguably not "academic" at all. So: take it or leave it: Bubba, you linked to a paper that explores subtleties of physics. It has at least passed the bar of quality set by the Ph.D-level physicists at Nature Physics, but at least in the opinion of myself and a few other reference desk regulars, is not very enlightening or novel. This is critical: I don't accuse the paper of factual inaccuracy or error; just that it's not very interesting. If you read it, and understand it, you may make up your own mind. If you read it and do not understand it, consider whether it is worth spending several years of intellectual effort to bring yourself up to speed on the physics background. If so, the paper is interesting to you and you will be able to decide for yourself whether it is "correct" or "accurate." If you don't feel that the paper is important enough to spend time to understand, then you're in agreement with a lot of people. That's how modern science works: merit is secondary to relevance. And if I may try to reclaim a shred of modesty here: who am I to decide what's important or relevant in physics? I'm not professionally employed to work in quantum physics research; this paper is out of my domain area, and I've never been published in that journal... so my opinion is moot. Nonetheless, I have formed an opinion based on wide reading, as a physicist-turned-some-type-of-engineer, I still follow the scientific literature in a variety of topics that interest me.Nimur (talk) 05:42, 24 May 2012 (UTC)

I didn't read it because I didn't feel qualified to evaluate it. Which is why I asked here. Bubba73 ^{You talkin' to me?} 05:48, 24 May 2012 (UTC)

I'm not qualified to evaluate the paper, either, but I will say this: theoretical interpretations, especially ones that are trying to address big "philosophical" interpretations of the ontology (that is, the reality) of quantum mechanical interpretations, are hard to evaluate. It will take some time before one can say whether this has been accepted or rejected, and whether they are accepted or rejected for "good" reasons or not may or may not be apparent. There is little urgency to it, in any case. So I doubt anyone on here is really in a position to say whether this is right or wrong or not at this point, or whether it will or won't catch on. Plumbing the depths of quantum mechanical interpretation is not, at the moment, high on too many physicists' lists for research projects. If the different ontological interpretations of the wave function do not lead to interesting physical results, then the "who cares?" response will probably dominate except in popularizations. This is essentially what Nimur is getting at when he says it is not "interesting," I believe. I am sure he would agree that on a deep level the ontological nature of the wave function is an interesting question, but this paper doesn't change the physics too much one way or another. --Mr.98 (talk) 13:10, 24 May 2012 (UTC)

If it doesn't lead to different results, then you are right about "who cares" because it is a philisopical question instead of a scientific one. But they say that it does lead to differences. Bubba73 ^{You talkin' to me?} 04:58, 25 May 2012 (UTC)

What they show is that no theory of the form they consider can make the same predictions as QM. That does mean that if you want to make a post-quantum theory of that form, you have to make different predictions. But there's no evidence of the need for any such theory (and quite a lot of evidence against it). The theorem doesn't have any bearing on the predictions of QM or the correctness of QM. -- BenRG (talk) 22:06, 25 May 2012 (UTC)

I'm not sure why "philosophical" should translate as "who cares". I care what is real and what is not, whether it or not it affects predictions about pointer coincidences. --Trovatore (talk) 22:09, 25 May 2012 (UTC)

If two theories don't make a difference that can be tested, then it is not something science can answer (i.e. which one is real). Bubba73 ^{You talkin' to me?} 05:09, 26 May 2012 (UTC)

I don't see how that addresses the question of "who cares". Saying that science cannot answer a question is asserting a limitation on science, not on the importance of the question. --Trovatore (talk) 21:05, 26 May 2012 (UTC)

I think the paper is interesting, it's a sort of no-go theorem against the idea that the wavefunction is not real. One can take issue with some details in the paper, but then it should be the people say that the wavefunction is not real, who should come up with a theory in which this is so. So, it is actually very similar to Bell's theorem as pointed out by Looie above. There are loopholes there too, but then if you are going to say that there may be a local deterministic theory that explains quantum mechanics, the ball is in your court to demonstrate this. Count Iblis (talk) 15:40, 24 May 2012 (UTC)

And about the paper's publication issues etc., one could argue that the result is trivial and could have been shown in a much simpler way, and therefore does not merit publication. I would have to carefully re-read the paper (I read it quickly some time ago), but it isn't clear to me why an argument along the following lines could not be set up. If the wavefunction is not real then it seems to me that this would imply that in at least some cases, a pure state could be replaced by a suitably chosen mixed state without that difference being detectable. But we know that this is false, you can always (in principle) tell the difference. Count Iblis (talk) 16:17, 24 May 2012 (UTC)

(ec) I can summarize the formal part of the paper, at least. They consider the possibility that quantum states (wave functions) represent classical probabilistic distributions over some underlying kind of state, which determines the experiment outcome. Unlike the usual hidden variable setup, they are interested in the case where different quantum states sometimes (with some nonzero probability) map to the same underlying state. They rule out this case by a simple exercise in undergraduate QM.

So much for the math. Obviously no model of the sort they rule out has ever existed (it wouldn't have worked), but moreover I can't remember anyone ever suggesting, in so many words, that they thought that quantum states could have this interpretation. The authors try to read it into passages by Jaynes and Einstein, but it's suggestive that they couldn't find anything better. I think the reaction of almost anyone to the idea of such a probabilistic interpretation would be "no, that obviously won't work", even before this paper. The authors argue that when people say that the state vector mixes objective and subjective properties of the system that they must mean this. But the state vector does mix objective and subjective properties. For starters there's the relative state (many-worlds) versus orthodox version of the state vector—different quantum states, same experiment, same predicted outcomes. Their theorem doesn't address this because theoretically there's an experiment that can distinguish these cases. It's an experiment that's impossible to actually do because it violates both locality and the second law of thermodynamics, but it technically exists as an experiment in the standard formulation of quantum mechanics. Another example is that you can pick a different inertial reference frame and get completely different time-dependent state vectors, but the same experimental predictions. There's the Hilbert picture where the wave function doesn't evolve with time. There's the fact that it's not clear how to define a wave function for the whole universe, or what that would mean. None of these problems is solved by the paper. They say they've proved the reality of something, but they can't say what.

It all feels to me like a "Gödel's theorem, therefore God" kind of argument. It will get rave reviews from a certain contingent of people who already believed in God, and the real meaning of those reviews is "finally, something that's sure to convince the nonbelievers". And each of them has their own private conception of God which they will think is vindicated by the argument. And it probably will convince some of the more impressionable nonbelievers. And we'll never be rid of it. We're still stuck with Wigner's friend, and that was a worse paper than this one. -- BenRG (talk) 16:30, 24 May 2012 (UTC)

May 24

Calories in coffee

Does a cup of coffee have any calories in it? Or is it really simply water (i.e., no calories)? Assume that the cup of coffee that I drink in the morning has no sugar or milk (or anything else) added to it. Am I drinking a calorie-free drink (like water) ... or am I actually consuming some calories? If the latter, how many calories are there in a cup of coffee? Thank you! Joseph A. Spadaro (talk) 00:59, 24 May 2012 (UTC)

Type "calories in black coffee" into google and you'll get your answer about 100 different ways. They all roughly agree. I won't insult you by linking any of the dozens of of answers you get. --Jayron32 01:03, 24 May 2012 (UTC)

Yeah, but the first five pages I got of that included nothing close to a Wikipedia-grade reliable source (a reasonably low bar already). But searching coffee calories did get me to [5] from the Mayo Clinic, which says "A plain cup of brewed coffee has only two calories (and no fat)" while listing off the calories of various additives. Wnt (talk) 02:32, 24 May 2012 (UTC)

From a reliable secondary source, instant coffee powder has 424 kJ per 100 grams, 101 kcal/100g 13.6% protein, 10% carbohydrate, 0.6% fat. ISBN 9780644138710. Graeme Bartlett (talk) 11:54, 24 May 2012 (UTC)

Yeah, but the question is about coffee (not that other abomination to which you refer). -- ♬ Jack of Oz ♬ ^{[your turn]} 20:38, 24 May 2012 (UTC)

Mcdonalds says 0. Shadowjams (talk) 21:01, 24 May 2012 (UTC)

I guess they round down because they can. There are calories in brewed/espresso coffee but compared to total daily energy intake it should be negligible and dwarfed by accounting errors in the rest of the energy intake total. Diet coke territory. SkyMachine ⁽⁺⁺⁾ 22:53, 24 May 2012 (UTC)

Thanks to all! I appreciate the input! Joseph A. Spadaro (talk) 01:01, 27 May 2012 (UTC)

Super Heros and capes

I know that super heros are just entertainment and thus not really "bound" to our laws of physics. But, would a super hero with a cape (Superman, Thor, Batman, etc.) not have a lot more difficulty flying with that thing strapped to their neck (not to mention being strangled!). Any idea as to just how much drag such an item would create? 99.250.103.117 (talk) 07:39, 24 May 2012 (UTC)99.250.103.117 (talk) 07:44, 24 May 2012 (UTC)

This is the kind of question that flagpole manufacturers would know how to answer, as the strength of the pole will determine the maximum size of flag it can support at a particular wind speed. Roger (talk) 07:53, 24 May 2012 (UTC)

Anyone capable of flying on their own would, I expect, have a sufficiently strong neck to handle the strain. Last time I looked, Batman doesn't fly under his own power, just swoop around a bit, though I would venture to guess his costume would be sufficiently rigid to prevent neck injury from the darned cape getting snagged on something. Clarityfiend (talk) 09:56, 24 May 2012 (UTC)

I think this topic was properly covered in the movie "The Incredibles"! Zzubnik (talk) 12:45, 24 May 2012 (UTC)

Thinking about it, when humans are doing the closest thing to flying (i.e. falling out of a plane) we use sheets of fabric to create drag (i.e. a parachute or a wingsuit). Some incarnations of Batman use the cape a bit like a glider - he's not really flying, but "falling with style". Other supers have no excuse however. LukeSurl ^{t c} 16:40, 24 May 2012 (UTC)

...which was, in turn, inspired by a similar discussion in Watchmen. 109.155.32.126 (talk) 20:10, 24 May 2012 (UTC)

Batman doesn't fly, he just glides, like a "flying squirrel". Superman originally only leaped great distances. Flight came a little later. The cape seldom serves any practical purpose. It's for show, for drama. In general, superheroes with their capes and tights were intended to remind the reader of the circus. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:36, 26 May 2012 (UTC)

I'd also like to add that in comic books (which are composed of still images) one can only show motion through distortions in cloth, trail lines, and other artificial means; thus, artists—at least in the golden age of comics—used the shape of the heroes' capes to depict flying/falling/running/drag in a non-moving image. Pine (talk) 04:00, 26 May 2012 (UTC)

Geology of DRC

What is the origin of the giant striations, running in an East-West direction, across Nord-Kivu province? Located at approximately -0.85 decimal degrees latitude. Plasmic Physics (talk) 10:32, 24 May 2012 (UTC)

They're a set of ridges, presumably related to different dipping rock layers, like cuestas, with variable resistance to erosion. I'll try to find out some more. Mikenorton (talk) 19:29, 24 May 2012 (UTC)

The ridges are located at the northern edge of the mesoproterozoic metamorphic belt known as the Kilbaran Belt, but I still don't know what the specific rock types are. Mikenorton (talk) 20:05, 24 May 2012 (UTC)

Which way do they dip? Plasmic Physics (talk) 23:13, 24 May 2012 (UTC)

They appear to be south-dipping, but that's pure OR. Mikenorton (talk) 06:07, 25 May 2012 (UTC)

Taxonomical names

This might be better at the Languages desk, but I figured the biologists here would know... how do you pronounce the Latin name for a species if it's based on a name in a non-latin language? For example: Hernandez-Camacho's night monkey is named after Jorge Hernandez-Camacho as Aotus jorgehernandezi. Would I say "Aotus Jaw-Gay-Her-Nan-Dez-Ee" or "Aotus Yor-Gay-Her-Nan-Day-Ee"?

This is the sort of thing that keeps me awake at night. Yunshui 雲‍水 10:42, 24 May 2012 (UTC)

Note that neither of those pronunciations equates to the Spanish pronunciation. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:30, 24 May 2012 (UTC)

I could also use some advice on the pronounciation of names in Spanish... Yunshui 雲‍水 11:57, 24 May 2012 (UTC)

"Jorge" is pronounced "Hor-Hay" in Spanish. --Mr.98 (talk) 12:57, 24 May 2012 (UTC)

Thanks. So: "Jaw-Gay-Her-Nan-Dez-Ee" or "Hor-Hay-Her-Nan-Day-Ee"? Yunshui 雲‍水 13:32, 24 May 2012 (UTC)

I'm told that in Mexico at least, Hernandez, (or more correctly Hernández), is pronounced 'air-NAN-dez'. (As a Spanish name, it would not have "I" on the end.) Wanderer57 (talk) 16:35, 24 May 2012 (UTC)

Yes, the "H" is silent, or effectively so. The trailing "i" is of course a Latinization, not a Spanish construction. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:28, 24 May 2012 (UTC)

IPA /ˈxorxe erˈnandes/; I guess the similar vowels would elide, so /ˌxorxerˈnandes/. — The rules of Spanish spelling are pretty easy, or at least seem that way to me because I learned them at age ~7. It always amazed me to meet educated people who had lived in California for twenty years without learning to pronounce Spanish names. —Tamfang (talk) 18:14, 24 May 2012 (UTC)

Whilst I'm genuinely grateful for the Spanish lessons, does anyone know how these rules of pronunciation work with respect to taxonomy (per the original question)? Yunshui 雲‍水 06:43, 25 May 2012 (UTC)

(Please bear in mind I speak from a position of ignorance, having little knowledge of either languages or taxonomy - sorry!) It seems like quite a lot of thought has gone into the pronunciation of scientific names eg. A guide to the pronounciation and meaning of cetacean taxonomic names (nothing given a Spanish name that I could see, but Danish, Turkish and Persian all represented.) This has some rules, but this (non WP:RS?) suggests they might be more like guidelines. This discussion suggests that there may not a be a universally recognised set of rules. Notes on Topical Dendrology says

Being in Latin, the scientific names are pronounced like Latin

words. The Latin language is pronounced almost like Spanish, and the vowels are similar in both languages. Then, it is simple and easy in Spanish-speaking countries to treat the scientific names as if they were written in Spanish. However, there are some names derived from foreign words, such as modern languages. These names are pronounced as in the original language, often with accent different from Spanish. The British and other Europeans pronounce scientific names correctly according to Latin, but in the United States these words generally

are spoken as if English.

I don't know if any of this is useful; from what I've read, the answer often seems to be, "meh, however you want really". --Kateshortforbob _talk 16:01, 25 May 2012 (UTC)

Jolly helpful, thank you. Yunshui 雲‍水 07:47, 28 May 2012 (UTC)

What class is a fox?

Apparently this was on an exam paper today in the UK: "A fox is a vertebrate. What class is it?" It stumped everyone, teachers included. Anyone? --TammyMoet (talk) 15:14, 24 May 2012 (UTC)

Mammalia of course! That such a simple, easy question can stump even teachers is a pretty serious indictment of the standard of education in the UK. Roger (talk) 15:27, 24 May 2012 (UTC)

Well the consensus was Mammals, but a quick Google got the answer "Chordata". What's the difference? --TammyMoet (talk) 15:36, 24 May 2012 (UTC)

From the fox article:

• Kingdom = Animalia
• Phylum = Chordata
• Class = Mammalia
• Order = Carnivora
• Family = Canidae
• Tribe = Vulpini

--LukeSurl ^{t c} 15:48, 24 May 2012 (UTC)

Chordata is the Phylum. It is a far bigger and more diverse grouping than Mammalia, which is the Class. For example, Chordata includes fish. Wanderer57 (talk) 15:53, 24 May 2012 (UTC)

BTW In what grade (age) was this question asked? Roger (talk) 16:03, 24 May 2012 (UTC)

Thanks to LukeSur for the comprehensive answer. I believe it was a GCSE question but will check. --TammyMoet (talk) 17:35, 24 May 2012 (UTC)

If it really is a GCSE question and even the teachers!!! were stumped it's rather conclusive proof that British education standards have "gone to the canidae"! Sad if one considers that this is the nation that just a few generations ago ruled almost half the world! Roger (talk) 18:20, 24 May 2012 (UTC)

Maybe part of what is going on here is that Linnaeus's levels are increasingly seen as not very meaningful. Every level between phylum and genus is basically arbitrary, and modern biologists tend not to find them useful. Looie496 (talk) 19:11, 24 May 2012 (UTC)

Indeed, modern taxonomists seem to prefer the clade system, which highlights actual decent from actual ancestors, rather than sometimes arbitrary and superficial physical characteristics present in the old Linnaean system. --Jayron32 19:17, 24 May 2012 (UTC)

(ec) Clearly their problem was that they spent their time memorizing answers to Trivial Pursuit questions, and thereby lost their empire to smug upstarts who are unable to restrain their gratuitous use of exclamation points.

Speaking as someone who makes a living in the field of biochemistry and who works with people who spend their days making phylogenetic trees, my response to this anecdote would have to be...'so what?' Faced with the same question, I'm not sure that I would have been able to snap off the correct answer either. What I could do is demonstrate a grasp of the more important underlying concepts— foxes are carnivorous canine mammals; foxes are vertebrates; and foxes are animals; all mammals are vertebrates (with all that implies), but not all vertebrates are mammals. Knowing which sets are proper subsets and supersets of one another is, practically speaking, more useful and meaningful than memorizing the somewhat-arbitrarily-defined Linnaean taxonomic levels and labels. (Any modern evolutionary biologist or geneticist is going to ask, why is Aves (birds) its own class, even though birds are descended evolutionarily from Reptilia—also its own class? Is it constructive to enshrine and glorify historical accidents like these as part of a strictly-taught hierarchical model?) TenOfAllTrades(talk) 19:32, 24 May 2012 (UTC)

Indeed, Saurischia and Ornithischia were orders. Now we list Saurischia as a "clade". ;) Still, such historical terms are not entirely useless, as they give some sense of the overall degree of 'difference' people perceived among various taxonomic units. Such imprecise and arbitrary notions are nonetheless difficult to replace. Wnt (talk) 20:28, 24 May 2012 (UTC)

The very fact that an exam question asked about the class of some creature suggests that knowledge of the Linnaean system is still required and is still taught. But is it really true that not a single teacher in the entire country knew the answer, Tammy? Who's the "everyone" you refer to? -- ♬ Jack of Oz ♬ ^{[your turn]} 20:29, 24 May 2012 (UTC)

If we're having a rant about the UK education system, then my 1.3 pence is that this sort of rote learning is largely pointless in the current period. If you need to know a specific fact such as this there's ample places one can look it up. Hell, I even hear that there's this free encyclopaedia on the internet these days. What we should be teaching children is how to find such information, and the methods of thinking required to understand the information once it's found. LukeSurl ^{t c} 21:48, 24 May 2012 (UTC)

I'd be very surprised to find such a question on a GCSE paper, unless it had already provided context that would allow to you remember that 'mammal' was the sort of answer it wanted (or, horrors, it was multiple choice). Do we know what exam board this was, and whether it was from a Dual Science Biology paper, or from a separates sciences Biology paper? I'm curious to know who includes this knowledge on the current curriculum. 109.155.32.126 (talk) 22:15, 24 May 2012 (UTC)

The question sounds like an attempt to test whether the candidate knows what a "class" is. If you know any classes, Mammalia is the one you're going to know, so they're testing if you know where mammals appears in the hierarchy. I remember being taught the hierarchy at either GCSE or AS level (with the mnemonic "Kill PC Oswald, for God's Sake!"), about 9 or 10 years ago. I wouldn't be surprised if it is still on the syllabus. --Tango (talk) 11:56, 25 May 2012 (UTC)

Back again. Apparently it was GCSE Biology, and the teachers present in the exam hall were discussing after the exam with other teachers (in the staff room). It had not formed part of the syllabus and therefore was not taught, so shouldn't have been in the exam - that's bad practice. Don't know the exam board yet, will ask. --TammyMoet (talk) 09:15, 25 May 2012 (UTC) More clarification: Biology section of a Combined Science GCSE. Still trying to find the board. --TammyMoet (talk) 13:22, 25 May 2012 (UTC)

For non-UK readers, the GCSE exam is generally intended for age 16 plus, and is of course, much easier than it used to be (that's my excuse and it I'm sticking to it). Alansplodge (talk) 21:29, 26 May 2012 (UTC)

Orange segments

I am curious about the segments (slices) in an orange fruit. What do they correspond to, relative to the structures in the flower? --İnfoCan (talk) 15:16, 24 May 2012 (UTC)

The segmentation already exists in the flower's ovary. Roger (talk) 15:52, 24 May 2012 (UTC)

You may be interested in the mutation navel orange that contains an additional set of smaller segments of a conjoined twin. See the article Orange (fruit). 84.209.89.214 (talk) 18:26, 24 May 2012 (UTC)

Household uses for reactions

I would like to know where the following reactions:

• Is found in the household/everyday life
  
• And what is positive an negative about each of the reactions.
  

1. Acid ± metal→ salt ± hydrogen
   
2. Acid ± metal oxide → salt ± water
   
3. Acid ± metal carbonate → salt ± water ± carbon dioxide
   
4. Acid ± alkali → salt ± water
   

Thanks. — Preceding unsigned comment added by 41.123.76.163 (talk) 15:39, 24 May 2012 (UTC)

I have two questions for you, which may help others (or even me) to answer your questions. First, why would you like to know that? Second, what other research or investigation have you done other than asking here? (Even if the research, e.g. web searches, didn't produce any useful answers - what did it produce?) Third, what ideas of your own do you have on this so far? --Demiurge1000 (talk) 18:09, 24 May 2012 (UTC)

The signs "±" in the question should all be straightforward "+". 84.209.89.214 (talk) 18:18, 24 May 2012 (UTC)

Not trying to do your homework for you. But, I take to acid to mean a Bronsted acid, which loses a proton in solution to leave the conjugate base behind, e.g. the metal salt of carbonic acid is a metal carbonate after the protons are reduced by the metal. (And of course the proton is not naked, but rather in the form of hydronium and higher-order species.) Two protons can be reduced by a pair of electrons to form dihydrogen (H2).

In your first case, the metal reduces (gives up a pair of electrons) the acid and thus becomes positive. The conjugate base is the acid that has lost a proton, so since a neutral species that has loses positive charge must be negative (conservation of charge), the conjugate base is negative. The salt is the combination of the positive metal cation plus the negative conjugate base, which must balance to give neutral species, if the metal and the acid both started out positive (this is not always the case, i.e. sodium dihydrogen phosphate is a negative ion that is still acidic and can lose a proton to become more negative).

In your other cases, (metal oxides, metal carbonates, alkalis), are combinations of metal cations plus some sort of negative ion (oxide, carbonate or hydroxide). The negative ions are in general, basic, and will receive a proton to become their neutral form. Oxides receive protons to become water or hydroxide, carbonates receive protons to become carbonic acid, which are unstable and decompose rapidly to carbon dioxide and water, hydroxides receive protons to become water. Hydroxides are quite basic. Water-soluble oxides (a charge of 2-) are very basic. If you dissolve sodium oxide in water, an explosion will happen.

In some cases, the metal and oxides form stronger bonds with each other than the solution. Acid sometimse brings the insoluble oxide into solution in the form of water, which forces the remaining metal cation into solution as well, which will be balanced by what remains of the acid after it loses a proton: the conjugate base. Remember that the combination metal cation + conjugate base is a salt. This is why mild acid can clean rust -- the insoluble iron oxide is dissolved leaving the clean metal behind (the acid is too weak to oxidise the metal). Nothing gold can stay (talk) 18:28, 24 May 2012 (UTC)

An "everyday household" example of #3 occurs in baking when baking powder reacts to release CO₂. Roger (talk) 18:33, 24 May 2012 (UTC)

#1 is used in etching. #2 is used in dissolving rust. And you can etch silicon dioxide (glass) with acid too -- silicon is a semimetal. #3 can be found in ocean acidification -- acid breaking down the calcium carbonate shells of lifeforms (close to insoluble in neutral water, but gets increasingly soluble in acid). #4 happens when you want to clean up either acid or base by dissolving it with the other. Nothing gold can stay (talk) 20:08, 24 May 2012 (UTC)

Why does LASIK work?

The article LASIK fails to cover any basic optical theory, i.e. why ablating the cornea or creating a flap would result in higher refractive power. If you don't change the curvature of the entire lens as opposed to a small section, wouldn't it just increase optical aberrations? Can someone enlighten? 76.104.28.221 (talk) 17:37, 24 May 2012 (UTC)

The cornea usually is thinner after LASIK, because of the removal of part of the stroma. This should reduce the optical power of the cornea, which accounts for about 2/3 of the eye's total optical power, and is the change needed to correct myopia. 84.209.89.214 (talk) 18:14, 24 May 2012 (UTC)

But wouldn't you need to thin the cornea everywhere? Otherwise you would get optical aberrations (some of the rays are focused but some aren't). Nothing gold can stay (talk) 18:42, 24 May 2012 (UTC)

My wife had Photorefractive keratectomy, which is a closely related procedure. IIRC, the idea is that there is enough focusing power in the cornea to make corrections such that the lens itself doesn't need to be reshaped. In other words, the effect is like turning the cornea into a permanent contact lens; the cornea is reshaped so that it refocuses the light in such a way as to correct for the abberations in the lens, much as a contact lens would. At least, that's what I remember from what my wife was told. --Jayron32 19:14, 24 May 2012 (UTC)

I think the cornea is reshaped so that focal properties of the entire area of over the pupil are changed. It's not the whole cornea, but the whole part that transmits light to the retina. SemanticMantis (talk) 21:53, 24 May 2012 (UTC)

Also, what are the physics behind LASIK? How do doctors know how much to correct for? How does the Lensmaker's equation apply to LASIK surgery? Nothing gold can stay (talk) 19:07, 24 May 2012 (UTC)

The lensmaker's equation is for lenses in air. It does not apply to either the cornea or the eye's lens. The same fundamental principles apply, but a more detailed analysis is required to look at how the cornea and lens interact to form an image.--Srleffler (talk) 06:37, 25 May 2012 (UTC)

Solar flares and radioactive decay

According to this 2010 report, http://news.stanford.edu/news/2010/august/sun-082310.html, there is a connection between solar flares and a change in the rate of radioactive decay measured on Earth. Has this connection been confirmed or debunked since then? At Radioactive_decay#Changing_decay_rates there is discussion of the phenomena, which concludes that there is "no evidence for such correlations", but all the references in that article pre-date the 2010 news report. Happy editing! (talk) 19:42, 24 May 2012 (UTC)

Neutrinos are definitively not the culprit, and the Purdue team is attempting to use the effect to predict solar flares. So it looks like there is still more science to come on this topic; indeed, I believe a lot more experiments are needed to find out what is happening, even if it's just experimental error (still the only culprit that makes physical sense according to current theories). -RunningOnBrains^(talk) 20:20, 24 May 2012 (UTC)

Where cometh the meme about heorin being less adictive than tobacco?

It's total rubbish that nicotine even TOUCHES the addictiveness of opioids, once one has a decent habit going. Where did this rubbish come from? Is there the slightest peace of "scientific justification" for it? Egg Centric 22:23, 24 May 2012 (UTC)

It depends how you measure addition, and whether you are talking about nicotine in isolation or in the presence of tobacco (which complicates the chemistry). Our article on it (Nicotine#In_the_central_nervous_system, Nicotine#Psychoactive_effects) covers this with citations. It is not "rubbish"; the source seems to come from FDA studies done in the 1980s and 1990s. It is true, of course, that you don't see people robbing stores (too often) to feed their nicotine habits — but that is as much a social constraint as any pharmacological one (the legality of nicotine makes it pretty easy to obtain, and the effects are not as profound as heroin). --Mr.98 (talk) 22:34, 24 May 2012 (UTC)

Well that lack of profundity tis the key - while heroin can be hard to get ahold of (and is more expensive) there is no comparison between acute withdrawl from the two. And even LESS comparison between the PAWS from the two. So by what means can they be called more addictive? Egg Centric 22:43, 24 May 2012 (UTC)

I found this 1987 NYT article: NICOTINE: HARDER TO KICK...THAN HEROIN. The sensationalist headline seems to be based on not much more than anecdotal evidence really. The general public's, and public policy's, thoughts on drugs are often massively bereft of evidence, instead being based on fear-mongering and tabloid headlines (c.f. the tale of David Nutt, who basically got fired for presenting the evidence in the diagram right) --LukeSurl ^{t c} 22:45, 24 May 2012 (UTC)

There is an irony in that were opioids legalised I am convinced they would do sod all damage. Basically you're talking about constiptation as the worst side effect (not the case for some like dextroproxyphene and pethidine but addicts can easily be moved off them to better 'uns) , and that can be combated by orally taken naloxone, biovaliable in ones gut. Nevertheless, while these wonderful chemicals stay illegal addiction to them is hellish at least some of the time (speaking from experience - I have done the occasional opioid treatment thingy and am about to start again, I currently take the equivilant of 280mg of morphine a day, I can afford this being a trader but even with a job as stupidly well paid as mine wasting 75k a year isn't ideal) and to compare it to nicoteine is honestly laughable; I have no idea where these reports are coming from but can only assume they're self serving... Egg Centric 22:49, 24 May 2012 (UTC)

Because heroin is illegal, very little serious research can be conducted into its effects, meaning that bigots can claim whatever they like. HiLo48 (talk) 23:26, 24 May 2012 (UTC)

My uncle was euthaniased with heroin [-]last week[/-] (checked it was a fortnight ago) (using doctrine of double effect as a legal excuse - I'm not exaggerating here btw, it was agreed with family and doctor - he had a funeral this tuesday) there's no reason in principle heroin couldnt' be experimented with in the UK that I'm aware with, I would think the political pressures ain't that strong... Egg Centric 23:35, 24 May 2012 (UTC)

Euthanasia using heroin is completely new to me. I hope you're doing well.

The obvious study would be looking at heroin and smoking addicts in jail and offering them the choice between an unlimited supply of cigarettes and an unlimited supply of heroin (or possibly methadone) for the next 4 weeks. I cannot find such a study (and I don't think ethical reasons would forbid such an experiment in for example The Netherlands). My gut feeling is that this meme is invented by anti-smoking lobbyists. Joepnl (talk) 23:44, 24 May 2012 (UTC)

Erm, an unlimited supply of heroin for jail inmates of anything other than the shortest sentences is only going to lead to one thing. BTW letting folk do as much methadone as they like would be even worse in that it would be far more likely to lead to lulzy deaths, for reasons not terribly interesting Egg Centric 00:51, 25 May 2012 (UTC)

http://www.bbc.co.uk/news/uk-11660210 Count Iblis (talk) 01:05, 25 May 2012 (UTC)

What's got alcohol to do with this? Joepnl (talk) 01:08, 25 May 2012 (UTC)

I've no idea why he mentioned that, but I would agree with the user. Alcohol is not as addictive as heroin (or even nicotine) but it is a MASSIVELY hard drug. It always amuses me to see anti-drug types who've taken it to huge amounts. How silly they look... But they'll never understand...

Memes can make jumps. So, when you have a news report about research showing that alcohol is more of a problem than heroin, and people also read about nicotine in relation to drugs, then these things can get mixed up, producing the meme about nicotine being less addictive than heroin. Count Iblis (talk) 01:26, 25 May 2012 (UTC)

Some years ago I assisted (as a volunteer) in a not-for-profit organisation providing rehabilitation to drug adicts. We were taught that there are three levels of adiction: 1) physical dependence, 2) pyschological dependence, and 3) habituation. Heroin is an example of physical dependence - it mimics a natural brain chemical, and the brain adapts by cutting back natural production (hence withdrawal symptoms). Psychological dependence is somewhat complex, but alchohol is the classic example, where alcholics get drunk to avoid their problems. Habituation is where environmental cues remind you of your craving. An example of habituation is craving tobaco when you see a friend light up, of getting a craving after dinner, if that's when you usually smoke.

Generally, physical adiction is the strongest, though if the drug does not closely match the natural analog, it may not be. Psychological addiction is the next strongest. Habituation is the weakest. But paradoxicaly, some people can break the strongest physical addiction by making their mind up, and others cannot break habituation.

From the above, some general principles emerge:

A drug that operates at all three adiction levels is the hardest to break and is thereby the most damaging. Heroin is the classic example. Tobacco is an example that works mainly be habituation, and very weakly in psychological adiction.

To get someone off drugs, you, and the addict, need to understand how the drug works in this context. If it works by physcial addition, you need to break that - cold turkey and replacement (as in methodone) are the (very imperfect) usual methods. If the addiction is psychological, you need to adress what in their life is bad - solve the problem or show that it is not so important. If the addiction is habituation, change their environment to get rid of the cues.

It should never be forgoten that with drugs such as heroin, that while the addict has a good supply, he/she thinks life is really good and their perception of themself and their life is distorted. Thinks like Western Govt "Just say no" programms sound about as sensible as saying the moon is made of cheese.

Opiates are disease masking. When heroin addicts came to us expressing a wish to get off it (usually when their supply has become a little unreliable), the fisrt thing we did was take then to a doctor for a really go checkout. Occaisonally they had broken bones and/or serious kidney or liver disease - and they didn't know.

I hope that, if you read through all this, you have some understanding that the graph the OP posted is roughly about right. I've simplified the story somewhat. I would move some drugs about on the graph to a certain extent. Barbituate addiction is pretty nasty. I smoked as a teenager but found the habit easy to break. :Wickwack124.182.14.180 (talk) 01:20, 25 May 2012 (UTC)

You smoked barbituates? wtf? EggCentric

Nah - I meant I smoked tobacco. Wickwack124.182.14.180 (talk)

re the rest of your thoughts... I'll be back to you some time in the next 292 hours... Egg Centric 01:39, 25 May 2012 (UTC)

As for why people think nicotine is more addictive, it might be because more people are addicted to nicotine than heroin. Of course, the reason for this is that more people try nicotine, not that it's more addictive. StuRat (talk) 04:02, 25 May 2012 (UTC)

That's a good example of a logical fallacy. --Aspro (talk) 17:15, 25 May 2012 (UTC)

There are other reasons to reinforce the nicotine habit in a real-life scenario. Serious studies could have real people as the object of study and, due to the social acceptability of tobacco and the behavioural triggers, come to the conclusion that a nicotine addicition is harder to get rid off. It's not all about the substance. — Preceding unsigned comment added by OsmanRF34 (talk • contribs) 01:07, 27 May 2012 (UTC)

May 25

Two questions

Scientist said that Black hole pull everything even light. As I know light is made of photons which are massless, they say. How is than posible that gravity affect them? Second question. Scientist said that electromagnetic force do not affect neutrino particles. I ask how than do the experiments with neutrinos in CERN? Which force they use to accelerate them and keep them inside? They said that neutrino pass through any mater. How than keep them inside? I will be very appreciative for answer. If anybody know answer, please tell me. — Preceding unsigned comment added by Parket7 (talk • contribs) 00:11, 25 May 2012 (UTC)

Photons don't have zero mass, they have zero rest mass. You should know that mass and energy are identical, so having mass means the same thing as having energy. Since photons have energy, they have what is called relativistic mass which is why they are affected by gravity. They are subject to gravitational lensing for example. The fact that gravity affects photons explains why they can't escape a black hole: the path the photons travel get "bent" as they pass any other mass, and black holes have enough gravity to "bend" their path inward, so they can never escape. As far as neutrinos: neutrinos have a very tiny, but non-zero cross-section, which means that, while the likelyhood of a neutrino interacting with another particle is very very small, it isn't zero. So, while you are being bathed in uncounted trillions of neutrinos every second, every few years one of them might interact with one of your atoms. It isn't much, but it is enough to prove the exist and catch one once in a while. Being electrically neutral doesn't mean that something is hard to catch, neutrons are fairly easy, and have no electrical charge of their own. --Jayron32 02:37, 25 May 2012 (UTC)

Black holes (or any massive object) can bend light. Isn't there a threshold for how close a photon can get to a black hole without getting "sucked in"? I'm assuming it has something to do with an inverse-square relationship, but my brain is getting foggy at this point. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:29, 25 May 2012 (UTC)

That would be the event horizon. 203.27.72.5 (talk) 06:20, 25 May 2012 (UTC)

Indeed, photons are no different to anything else - the event horizon is, by definition, the closest they can get and still escape. The photon sphere is an interesting related phenomenon. --Tango (talk) 12:24, 25 May 2012 (UTC)

What accounts for temperature increase at night in a modern home?

I live in the UK. Hot day today. But hotter night, at least in this room. No air-con.

Is it heat beating down on the bricks outside during the day, the bricks absorb it, and are now releasing that heat into the room? I've also heard that cloud cover can trap heat, could that account for it? What if we assume no clouds? --bodnotbod (talk) 00:40, 25 May 2012 (UTC)

Are you describing real, measured temperatures, or how hot you feel? HiLo48 (talk) 00:46, 25 May 2012 (UTC)

He's describing how hot I feel.

To throw some numbers around, today in the UK the air temperature (outside) reached about 26C at about 5pm where I live. An hour or two later, the temperature inside my living room (not especially well ventilated) reached 23C.

Right now at about 2am, the air temperature outside is about 15C (an unusually warm night, for here). The temperature inside my living room is *still* (probably unsurprisingly) around 23C. So it's not more, but nor has it gone down appreciably. Humans tend to perceive this as "hotter" because it's during the night, maybe? --Demiurge1000 (talk) 01:00, 25 May 2012 (UTC)

Yeah, the heat stored in the bricks (and other parts of the building) would be a big part of the problem. Better ventilation would be a great solution, but maybe not practical. (If you have ever contemplated moving to Australia, please check our climate carefully. You may not like it.) HiLo48 (talk) 01:12, 25 May 2012 (UTC)

If you have electrical theory knowlege, the phenomena of some homes/rooms being hotter at night is very easy to explain. Before I try and put it in simple terms, don't forget that we have eveolved in a world where is is cold at night and cold in winter. The body feels comfortable with some natural diurnal and annual variation. If, for instance, you are in a room during the day at 25 C, you can feel cool, and if you are in a room at night at 25 C, you can feel hot.

The structure of a dwelling (eg bricks) provides thermal resistance, analoguous to electrical resistance. The flow of heat thru a resistance is restricted. The dwelling structure (and furniture inside) also provides thermal capacitance, analogous to electrical capacitance. That is, heat is stored. The two phenomena act to together like an electrical filter circuit comprising series resistance and shunt capacitance (see passive low pass filter at http://en.wikipedia.org/wiki/Low_pass_filter). Such filtering delays the incident variation. A simple room can delay the diurnal variation by a maximum of one-quarter of the varition period - ie 24/4 = 6 hours (an electrical engineer might regard this as a 90 degree phase shift). If the structure has a rood space or other rooms, it can act as two simple passive filters in cascade. In this case the maximum possible delay is 12 hours. However, a more likely total delay in a double brick dwelling with good ceiling insulation is about half that, ie around 6 to 8 hours. Wickwack124.182.14.180 (talk) 01:47, 25 May 2012 (UTC)

I generallly find evolutionary explainations quetionable particularly when not backed up by anything but 'it sounds right'. But in this case, it doesn't even sound right. Specifically who's 'we'? Plenty of humans have been living in regions close enough to the equator not to have the seasonal variation you speak of (they may still have seasonal variation although generally far less extreme and not of the same character). And while there is still diurnal variation, it's generally far less then I'm guessing you're thinking of, particular in sheltered areas (i.e. out of the blazing sun). Nil Einne (talk) 13:12, 25 May 2012 (UTC)

A certain room in my house (on the top floor facing west) absolutely gets hotter at night, if the windows are kept closed. I open the windows and put fans in them on high (half blowing in and half out). I leave them on for hours. Otherwise, I find that when I turn them off, the heat radiating from the west wall and ceiling heats the room right back up again. (I previously tried using a window A/C unit in there, but it ran continuously and couldn't keep it cool.) A 6 hour delay is just about right. Since the hottest part of the day is around 3 PM, the hottest temp in that room occurs around 9 PM. And yes, this is a brick house.

If you can't ventilate with fans, you could also try hosing down the outside of the wall at the hottest parts of the day. If you have a sprinkler system, set that up to spray on the wall. StuRat (talk) 03:49, 25 May 2012 (UTC)

The term is thermal lag. It can be exploited to good effect in places with high daytime temperatures and low nighttime temperatures (as in mid-altitude deserts), where it evens temperatures out. Adobes in New Mexico use mass to maintain an even temperature, for instance. It's specifically used in passive solar building design. Acroterion (talk) 03:56, 25 May 2012 (UTC)

I think that the effectiveness of opposite openings is often overlooked. A room with a fan still diffuses heat from one point. But a room with windows open to the east and west and even a slight prevailing wind, without any fan, will exchange its entire volume with the outside as the air moves along downwind. Wnt (talk) 04:48, 25 May 2012 (UTC)

I was talking about multiple fans, with some blowing in and some out, which exchanges all the air without the need for (natural) wind. Since my fans blow at the speed of a strong wind, on high, they should be more effective than a slight breeze. StuRat (talk) 04:55, 25 May 2012 (UTC)

If they are blowing in and out of the same window, then you may not be getting much air flow in the rest of the room. You would be better off opening a window on the other side of the building and leaving the doors open between them. You can use fans to increase the airflow if there isn't much wind, but you don't need much to get a big effect. --Tango (talk) 12:21, 25 May 2012 (UTC)

No, they are not the same window, for many reasons. Beyond the inefficiency that would cause, two of these box fans would never fit into one of my windows. The only rooms in the house which have only one window are the bathrooms. StuRat (talk) 16:08, 25 May 2012 (UTC)

Thanks very much for the answers folks. HiLo, my question related to measured temperatures as I have a thermometer in the room. I have done the opening windows across the house before and in spite of intervening walls dividing the rooms it does seem to work very well. --bodnotbod (talk) 12:35, 25 May 2012 (UTC)

My lounge room heated up considerably last night, after I switched the lights on. I have three 60W traditional globes and I was doing some close work and need to see. I'm surprised the temperature increase was noticeable. It was hot again today, and I've found a lab thermometer at work, so I'm going to see exactly how much switching the lights on warms the room. --TrogWoolley (talk) 13:18, 25 May 2012 (UTC)

You've raised a good point there. Yes, we use lights at night, and modern, energy efficient globes create a lot less heat than traditional globes. It's certainly made my poorly located home office here in Australia a lot more usable on hot summer nights. HiLo48 (talk) 17:41, 25 May 2012 (UTC)

Now would be a good time to replace those incandescent bulbs with compact fluorescent lamps. Not only will you save on energy, but you can also be more comfortable. And, if you elect to go with 100 watt equivalent blubs (which are really 23 watts), you will still save energy and also get more light. StuRat (talk) 17:50, 25 May 2012 (UTC)

Switching the lights on last night made it feel warmer, but the temperature in the room did not rise, indeed it fell during the hours I had the lights on. I must be feeling the radiant as I'm sitting right under the bulbs. It is time to change to these new-fangled ones! --TrogWoolley (talk) 16:26, 26 May 2012 (UTC)

Agreed. I imagine you could make the thermometer detect the radiant heat by covering it in a black cloth and placing it where the light shines. There could also have been a rise in humidity as you sat there, especially if you were sweaty. This would make it feel warmer, too. StuRat (talk) 17:00, 26 May 2012 (UTC)

Orange Plasma on ICP-AES

I've noticed something strange when analysing some water samples on an ICP-AES. Usually, when looking through the filtered viewing port into the plasma chamber, the torch appears to give off a deep green light. For some reason, these water samples change the colour to a bright orange. Generally, I don't get samples with high sodium content. I can't test for sodium with the methods set up on this instrument, but is it possible that high levels of sodium ion are causing the colour change? If not, what constituent could be causing the change? I'm also frequently encountering an error that the plasma impedence is too high. Could this be caused by the same thing that's causing the orange glow? 203.27.72.5 (talk) 06:15, 25 May 2012 (UTC)

I don't have any experiential knowledge of the apparatus, but could Rayleigh scattering or Tyndall effect be involved? {The poster formerly known as 87.81.230.195} 84.21.143.150 (talk) 12:08, 25 May 2012 (UTC)

The Tyndall effect is out, as it applies to colloids, and I think Rayleigh scattering is highly unlikely, given that the light is only travelling about 30cm to reach my eye, and that the plasma has a lower electrical polarizability than air (since it's already substantially ionized). 203.27.72.5 (talk) 21:04, 25 May 2012 (UTC)

Hand clap

Is it true: when you clap your hands, at the moment of contact, temperatures in excess of a couple thousand Kelvin are generated for someting like a nanosecond? Plasmic Physics (talk) 09:21, 25 May 2012 (UTC)

That seems highly dubious, in order to reach such extreme temperatures you would need to concentrate a lot of energy in a very small volume very quickly. For example, there is a theory that temperatures over 9000 K are reached in cavitation, but that is in the center of a bubble which is imploding with supersonic velocities. Yoenit (talk) 11:02, 25 May 2012 (UTC)

Has PlasmicPhysics caught that Dorothy Dixer disease from WhoopWhoop? I suspect, given Plasmic's background, that he is aware that questions on the temperature rise caused by clapping, banging two bits of wood together, and the like, is a favorite amongst those who write college and undergrad physics textbooks. For those not familiar with the British parliamentary system as used in Britain, Australia, and elsewhere, a "Dorothy Dixer" is where someone asks a question to which he already knows the answer (or, alternatively, asks a question so that a colleague can answer in order to look good. The temperature rise possible is fractions of a degree, and is easily estimated from calculating the kinetic energy (mass of arm/hand, and velocity at impact), and the specific heat of flesh, assumed to be as per water, and a couple of other simplifying assumptions. Ratbone124.182.7.166 (talk) 11:38, 25 May 2012 (UTC)

There's an article about that, BTW OsmanRF34 (talk) —Preceding undated comment added 16:09, 25 May 2012 (UTC).

It's probably going to depend on your definitions. Temperature is defined as an average, so if you talk about the temperature of a very small amount of matter over a very small timescale, then you can easily get extreme results, but they aren't particularly meaningful. --Tango (talk) 12:01, 25 May 2012 (UTC)

In special circumstances in theory, maybe. But in this case, upon impact the skin and some meat/gristle etc to a depth of a couple of mm or so gets deformed at the speed of closing. Within the context of the question, you can consider a peak temperature at a small point if you like. An average temperature is not implicit in the question. However the kinetic energy is dissipated over a volume of flesh equal to (roughly) area of hand multipled by depth of deformation. So it's not a very small amount of matter, it is a significant amount of matter with respect to the amount of kinetic energy. The time taken to deform the flesh is not infintessimal either, but can be assumed short enough that heat lost by conduction to surrounding tissue can be ignored. So you can't get extreme results. Ratbone124.182.7.166 (talk) 12:35, 25 May 2012 (UTC)

(edit conflict)I don't see why you made such a fuss about me asking the question. I'm satisfied with this answer, and unlike big Whoop, I'm not asking questions because I'm bored, or because I have an alterior motive. I'm genuinely interested in the answer. Plasmic Physics (talk) 13:01, 25 May 2012 (UTC)

No big deal Plasmic, I gave you the answer anyway. But I was a bit supicious, given that your own userpage says you are a Bsc, and your answers to other questions indicate you have good physics knowlege. As I said, questions on the temperature rise of hands on clapping, or temperature rise of bits of wood banged together, and the like are common in textbooks. Three of 4 physics books I own have a question asking for a calculation of temperature due to clapping; the 4th (the famous Halliday & Resnick dreaded by uni students thruought the English speaking world for 30 years) asks you to calculate the temperature of a nail after it has been hit by a hammer. You must have seen a similar question. Ratbone60.230.194.187 (talk) 15:15, 25 May 2012 (UTC)

But that considers the temperature after the heat has dissipated through part of the flesh. But what about before that? As I understand it, the air between the hands is compacted to a very high pressure, and because only a very tiny amount of air is trapped between the hands (and that air has very little mass to begin with), a small amount of energy can theoretically heat it by thousands of degrees. I do agree with Tango that such a 'temperature' may be quite meaningless, though. - Lindert (talk) 12:55, 25 May 2012 (UTC)

Just how quickly can you clap your hands? Dissipation of heat occurs on a nanosecond scale, much faster than the pressure can buildup. I wouldn't be surprised if deformation of your hand is also faster than pressure buildup, which means you never get a high pressure by clapping, just a deformed hand (no pun intended) Yoenit (talk) 14:07, 25 May 2012 (UTC)

You're probably right that heat dissipation is faster, I've never done the calculations (I was just speculating a bit). And yes, although there is definitely a local increase in air pressure (hence the sound), it's impossible to calculate how much without knowing how the hands deform. - Lindert (talk) 14:56, 25 May 2012 (UTC)

If you do do some calculations, or just think about things, like the amount of energy required in a loudspeaker to produce a clap sound of equal loudness, you'll find that the energy converted into sound energy is quite small compared to the kinetic energy delivered by the mass of the arm/hand. Therefore almost all the kinetic energy must be absorbed in the deformed flesh. As to how much the hands deform, just clap and see - it is limitted by the essentially rigid bones and is of the order of one or 2 mm. As the bones do not deform, they absorb no energy. Just how the hands deform beyond that simply does not matter. Ratbone60.230.194.187 (talk) 15:15, 25 May 2012 (UTC)

I remember reading somewhere that the sparks that are generated in a grinding machine have a temperature of thousands of degrees but are harmless to the human skin due to low heat content (because of low mass). This question is similiar to this. WikiCheng | Talk 14:00, 25 May 2012 (UTC)

Steel striking stones such as flint and quartz produces ignition temperatures high enough to occasionally ignite a few steel bits that fly away, forming the sparks we see, and there may be lots of clanking of the fairly hard hand-jewelry in a crowd... hummmmmm. One can produce these sparks with the force of ones hands and according to a quick google search, the ignition temperature of steel is 1500 degrees Fahrenheit, so we are somewhat near the ballpark here of a couple of thousand degrees. Modocc (talk) 15:37, 25 May 2012 (UTC)

It depends on how far they travel before hitting the skin, since objects that small rapidly cool while flying through the air. StuRat (talk) 16:04, 25 May 2012 (UTC)

It's not true, you can easily check this by clapping your hands in total darkness when your eyes are fully dark adapted. Temperatures in the thousands of kelvins range even confined to a very small area near the surface, should lead to ionization which should be easily visible. Count Iblis (talk) 16:44, 25 May 2012 (UTC

Without any jewelry you are right, and the OP didn't specify whether or not any is worn, but we have ample evidence that one can attain fairly high temps when hard jewelry is in place (which where I live is very common). Maybe not thousands of kelvin, but within the same order of magnitude 800+K. --Modocc (talk) 17:08, 25 May 2012 (UTC)

There is a phenomenon that produces extreme temperatures (confirmed up to 20,000 K!) on picosecond scales: Sonoluminescence. However in this case it is a completely sealed system with a much denser, incompressible fluid (water); I doubt the same effect would even be close to the same scale in a non-sealed system such as the "hand clapping" one. -RunningOnBrains^(talk) 20:12, 25 May 2012 (UTC)

Some background to this. Suppose I am hand clapping in the dark with gloves studded with quartz and steel. I will definitely see plenty of sparks! There is no question about this. For as a child I've personally, on numerous occasions, out of mere fascination and curiosity, easily sparked the edges of rocks with the edges of metal implements using very little to moderate force. According to our article on sparks, those sparks I created are burning bits of steel. If I remember correctly, from chemistry, ignition temperatures are needed. Thus, the sparks would not be observed unless I was initially creating these very localized and very high temperatures with these experiments. Perhaps someone that is more knowledgeable can correct me if I am in anyway wrong on this and my conclusion that its indeed possible and even probable, of course. --Modocc (talk) 20:40, 25 May 2012 (UTC)

Yes, in that case what happens is that the energy that is deposited locally at the contact area cannot get away easily, small parts break off and they have very high temperatures. However, this does not happen with your hands. In a biological system that has to maintain itself, that would create big problems. Count Iblis (talk) 22:18, 25 May 2012 (UTC)

Of course ones flesh would not and could not get very hot (clapping can warm the hands, and heart, though :-))! I never said or implied that it would. However, I've struck my terrible synthesis because its unclear from what I've read so far how hot the metal sparks can get cause I'm a too tired, too rash and why the blazes I am misreading stuff beats me. In fact, its starting to dawn on me, only now of course, that I made this exact same mistake of conflating "red hot globules" with combustion, once before... in a distant memory decades ago when I didn't know better and so I was obviously doomed and predisposed to repeat this mistake. I can't seem to stop repeating the same spelling mistakes either. :( --Modocc (talk) 22:36, 25 May 2012 (UTC)

Followup. In the very short time I've been trying to find out more about the actual temperature and any combustion of such sparks, I'm only more confused and befuddled, so any reliable sourced info would help. My sinus pain is getting worse too, so I need to take a break. Thanks in advance. PS, One source, not a reliable one though, indicated that sparks are propelled by an initial conflagration, which may explain my confusion, since there would be an initial combustion that expels the extinguished globules that the article mentions, but I've not read the lengthy source referred to yet. The metal alloy Ferrocerium does actually burn very hot, 1,650 °C, and has a relatively low ignition temperature, between 150 and 180 degrees Celsius. I'm still unclear about ordinary steel though. I just picked up a couple of quartz stones (I couldn't quite remember, so I was reluctant to assert this), and confirmed that knocking them together produces sparks too, and I've no idea how hot these are either, but probably not very hot since they are not used to start fires and the quartz has piezo-electric properties. I suppose too that iron can oxidize at different rates and temperatures, so there is no simple answer, other than to look for more data on this. --Modocc (talk) 00:02, 26 May 2012 (UTC)

It doesn't have any relevance to the OP's question, but if you see something glowing, eg sparks given off by striking metals and/or minerals together, you can quite easily estimate the temperature, using the principle of black body radiation http://en.wikipedia.org/wiki/Black-body_radiation. Black body radiation sensing is most accurate when the item that is radiating is "black" ie totally absorbent. If it is not, the apparent temperature indicated by the radiation is lower than the true temperature. If the item is transparent, the apparent temperature is zero. In practice, most metals and minerals are sufficiently close to being black body radiators. Alloys of iron are very close, aluminium is a notable exception. Dull red for steel is ~1500 C; Glowing yellow is about 4000 C. Artisans skilled in welding, cutting, and the heat treatment of metals except aluminium alloys go on the colour of the radiation as seen with their eyes - they don't bother with any sort of thermometer. Ratbone121.215.6.210 (talk) 04:18, 26 May 2012 (UTC)

Thanks Ratbone. Wedding bands and rings have been known to ignite gases such as propane and volatile vapors and if I remember correctly, platinum rings are particularly dangerous in this respect, since the metal catalysizes many reactions. Also, if I remember correctly, iron gets whiter with heat, but I was unsure about what temp it turned red. The article on sparks mentions that the spark globules from striking steel with flint are red. 1500 C is definitely above the ignition temperature of steel, so the globules must be oxidizing, at least on their surface.[striked because steel appears red at 1500F, not 1500C, per forging charts that I give below] The more I think about this, I doubt the steel's standard atm ignition temperature is entirely relevant, since local pressures may be somewhat elevated too when stones, crystals and/or ring bands bang against each other, but these effects are too transient to be significant normally. This study measured a fairly high ignition temperature for foils (preceded by some self-heating). --Modocc (talk) 06:59, 26 May 2012 (UTC)

The color that any hot substance glows is directly dependent on its temperature; see blackbody radiation. However combustion is a whole different animal, as a substance can have emission lines that change the color of the flame; for instance, sodium burns a brilliant orange, and iodine burns purple. See flame test for info on that. -RunningOnBrains^(talk) 07:54, 26 May 2012 (UTC)

I don't think that, for steel at any rate, the ignition temperature or radiation due to combustion is significant. If it is significant, then an awful lot of metalworking textbooks must be wrong. A quick google for "ignition temperature of steel" turned up all manner of unreliable sites giving temperatures from 800 C to 1500 C. However, to burn the Fe and C, you've first got to melt it, and the melting point for steel is around 1500 C. Really, only a gas can burn. Things that are not gasses burn because the heat of combustion is sufficient to pyrolyse (ie split up chemically with the pyrolysed products being gasses) the liquid or solid, or just vaporise it. The paper cited by Modocc is not fully accesible to me without paying for it, but appears from the sample page to be for pure oxygen, and they give the ignition temperature as >1600 C. Ignition temperatures for solid are gnerally much higher in air than for pure oxygen. Ratbone121.215.6.210 (talk) 08:21, 26 May 2012 (UTC)

I might need to modify my last post accordingly and will note too that I need to be more careful with googling random sites, because the net is both a blessing as I've more access than ever to obscure stuff and interesting discussions, and a curse too sometimes. In any case, you are correct about the pure oxygen, but the study here gives 1644K or 1391C for the cylinders and also gives a considerably lower surface temperature, 1233K, or 950C for foils which is significantly below the melting temperature and involves less mass. Thus I'm still left wondering if, according to some random guys on the net I've read, these iron particles that were at one time used to start fires have some if any self-heating due to oxidation. According to this random off the net chart steel turns red at a temp of only 760C! It then turns orange and orange-yellow as it gets hotter and, according to the description given, it says an oxidation layer forms???? Another more subtle chart confirms the other sites temps at least, so I'll assume instead of the figure of ~1500C you posted earlier, 1500F would be more accurate (and this explains some of the confusion). --Modocc (talk) 10:03, 26 May 2012 (UTC)

Oops! Our wikipedia article black body radiation http://en.wikipedia.org/wiki/Black-body_radiation needs some attention then, see the colour chart. However, the lower temperatures aprently required for balck body emission means that my thought that combustion can be neglected when assessing the temperature of hot metals is confirmed more strongly. Ratbone121.215.6.210 (talk) 12:37, 26 May 2012 (UTC)

Jupiter Rise?

Which way does Jupiter appear to cross the sky when it's visible in the Northern hemisphere? West-East or East-West? — Preceding unsigned comment added by 92.40.254.195 (talk) 11:43, 25 May 2012 (UTC)

Could be either one, depending on whether it's in "retrograde" motion as seen from the earth. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:52, 25 May 2012 (UTC)

Given the title "Jupiter Rise", I would guess the OP is talking about movement within one night. That is caused by the Earth's rotation, so it's east to west, like everything else. Movement between nights could go either way, depending on whether the Earth and Jupiter are relative to each other in their orbits, as you say. --Tango (talk) 11:58, 25 May 2012 (UTC)

Yes. The only things that rise in the west are prograde satellites below synchronous orbit, like Phobos. —Tamfang (talk) 21:09, 25 May 2012 (UTC)

Sunny weather and arthritis

Many arthritis sufferers say that their symptoms are eased to a large extent by hot sunny weather. Can anyone enlighten me as to the mechanism that might effect this please?--TammyMoet (talk) 13:41, 25 May 2012 (UTC)

There is probably no medical or clinical reason to explain that, although it is perfectly believable. My first instinct is simply that everybody loves "good" weather (I'd far prefer a raging blizzard to 28C and sunny, but I'm in a vast minority), and whereas when the weather is bad people tend to remain around their homes without much physical activity, summer-like conditions draw people out and about. Now, arthritis patients may begin to feel better for any of several reasons: doing things like swimming and gardening take the mind off mild to moderate pain and make it seem less substantial; the sunny weather simply improves the psyche, making it harder to dwell on painful symptoms; or potentially that increased levels of outdoor activities work to liberate joints and muscles, reducing stiffness and pain. These are the most likely scenarios. From a meteorological point of view, sunny weather is associated with sinking atmospheric motion, ie. high pressure, and many patients report that their pain worsens in bouts of low pressure/storminess. It's conceivable that during extended periods of fair weather, symptoms nominally lesson until the next trigger of pain. Juliancolton (talk) 13:56, 25 May 2012 (UTC)

I agree with the air pressure as the cause. Higher air pressure will tend to reduce swelling somewhat. StuRat (talk) 15:49, 25 May 2012 (UTC)

I doubt that. Pressure will generally cancel out. What may have an effect is changing air pressure, since it takes time for pressures in internal cavities, etc., to equalise with the air pressure. That means when air pressure changes quickly (as it does immediately before a storm), there will be a short time when the internal pressure and the external pressure aren't equal. Then there will be a net force, and you may be able to feel it. (It's a mild version of what happens on a plane, so that would be a good test - how to arthritics generally find take-off and landing on planes?) --Tango (talk) 12:49, 26 May 2012 (UTC)

Being a sufferer, physical activity usually exacerbates arthritis. But blood is warmer so it flows faster and higher pressure means more oxygen in the air. Could help ease pain.165.212.189.187 (talk) 15:27, 25 May 2012 (UTC)

Ambient temperature has very little effect on core body temperature of a healthy individual. Your extremities may vary in temperature, but I don't think the blood would change temperature enough going through them to have a noticeable impact on its viscosity. The higher pressure isn't going to lead to sufficiently more oxygen to have a noticeable impact either - changes in air pressure are generally only a couple of percent. --Tango (talk) 12:49, 26 May 2012 (UTC)

ever hear of the straw that broke the camels back? You just explained two.68.83.98.40 (talk) 02:42, 27 May 2012 (UTC)

http://arthritis.about.com/b/2008/07/09/vitamin-d-supplementation-may-offer-pain-relief.htm

Count Iblis (talk) 15:56, 25 May 2012 (UTC)

The landed gentry with their lily-white-skins may have had this conditioned diagnosed first -because only they could afford doctors. However, could it be that the average English peasant, toiling outside in all weathers was never trouble by such a malady? Vitamin D levels in modern man have been noted as poor. --Aspro (talk) 16:51, 25 May 2012 (UTC)

It could also be that peasants never got old enough to develop arthritis... or that rheumatoid arthritis was brought over from the New World... believe me I've researched this/these conditions for years (they run in my family and I'm the latest in line) and there's all sorts of weird and wonderful theories regarding how RA especially developed in the Old World. Vitamin D has recently been linked with MS and cancer as well as the obvious (rickets), so it wouldn't surprise me to see it has an effect on arthritic conditions too. My 5x great grandfather's obituary (written 1897) cites rheumatoid arthritis as cause of death. He was the only one in his generation in his family to reach the age of 60, everyone else being glassblowers or miners. Anyway, other ideas are welcome as to why sufferers feel symptoms are eased in hot dry weather. --TammyMoet (talk) 17:15, 25 May 2012 (UTC)

Yes, I am aware of the life expectancy of those time, which is why I posed it as a question, rather than come out with a statement. However, I choose the word 'peasant' with care. As you have taken the trouble look at archival records, have you noticed that they tend to 'only' record conurbations of about 5,000 souls or more? Not agricultural workers but artisans and the like. These crowded slums ran out of vegetables in late winter and scurvy was commonly recorded – especially in prisons and asylums, which bought the cheapest food stuffs. On top of that, the insanitary conditions mean that the poorer township populations were exposed to high levels of pathogenic organisms. So, this plus that lack of vitamins leads to the recently acknowledged phenomena that people whose ancestry is traceable to places like Glasgow (which was once a quaint little village on the side of the River Clyde and still beautiful even today) now have high a incidence of autoimmune disease. [6]. For the reason given above, we don't appear to have reliable records for the mortality rate of peasants in the country-side but the thinking is that it was lower for all age groups -compared with the towns and cities. Just has been observed in the wild life at Chernobyl. The population of towns and cites grew due mostly from the migration from uncontaminated country areas. Graveyards give witness to the high morality rate therein and so if half the children die before reaching puberty there can not have been the exponential growth to explain the expansion recorded without this constant influx - simple maths. Therefore, peasants didn’t develop rheumatoid arthritis because they didn’t live long enough! Rather (in my view) they remained free because there was no genetic advantage and they had year long access to vegetables (vitamin C) and sunlight (vitamin D). Rheumatoid arthritis is horrid, but I don't know of any modern medical advance that has enabled them to 'only now' survive past 60. Classic like Lark Rise to Candleford have poor old people in them. If you see my point.--Aspro (talk) 14:18, 26 May 2012 (UTC)

Not everyone will suffer from rheumatoid arthritis, which suggests a strong genetic component, and explains why not everyone in centuries gone by would have it. Osteo arthritis is a different kettle of fish and it is difficult to find any older person without some form of this condition in this day and age: I suspect this is the case in years gone by. Mortality rates aren't dependent on disease and health: living and working conditions also played a part (hence my mention of the glassblowers and miners in my family). And as for archival records, I have noticed no such thing about conurbations or the number of people therein. It may be different for other countries but England has pretty complete parish records from the mid-1500s, which predate by some way the industrialisation and urbanisation of the countryside. --TammyMoet (talk) 18:48, 26 May 2012 (UTC)

Raised temperature in itself can directly ease the pain of arthritis. ObPersonal: my grandmother suffered very badly from rheumatoid arthritis, and a treatment for temporary pain alleviation which I witnessed as a child/youth in the 60s/70s (and which I must presume was prescribed or at least sanctioned by her doctor) was for her to immerse her crippled hands or feet in barely-melted soft paraffin wax – I believe the particular wax was specifically formulated and sold for this purpose, though it's possible my grandfather (an engineer and an intelligent and resourceful man) repurposed it from another source. Paraffin wax has a high heat capacity and therefore cools relatively slowly, and the resultant gentle but persistant heat to which her hands or feet were thus subjected while immersed/encased was efficacious on the treated members.

I imagine subsequently developed drug treatments have rendered this form of therapy largely obsolete in conventional medicine (perhaps not entirely wisely, and googling suggests it is still promoted in fringe medicine), and I can't answer the OP's primary question of why sunny weather/heat helps. {The poster formerly known as 87.81.230.195} 90.197.66.211 (talk) 10:34, 26 May 2012 (UTC)

On the contrary, I have been prescribed paraffin wax treatments in the past by physiotherapists and am looking for my own personal wax bath so I can use it at home. It eases the pain in my hands for nearly a week at a time, something which no painkiller can do. --TammyMoet (talk) 18:42, 26 May 2012 (UTC)

I'm sorry to hear of your affliction, Tammy, and glad that the treatment helps. {The poster formerly known as 87.81.230.195} 90.197.66.211 (talk) 19:52, 26 May 2012 (UTC)

This page at Arthritis Research UK Can damp, cold conditions make osteoarthritis worse? supports the theory that it's to do with an improved feeling of well-being (or the other way round in this case). Alansplodge (talk) 21:18, 26 May 2012 (UTC)

Border control discovering smuggling inside the body

How do border control agents discover objects inside the body? Do they perform an X-ray, an ultrasound or stick a probe into people? 2 certainly seems to be the less inconvenient, but is it effective? — Preceding unsigned comment added by OsmanRF34 (talk • contribs) 16:01, 25 May 2012 (UTC)

Wikipedia has an article about this: Balloon swallower. Medical glove and large dollops of K-Y Jelly also facilitate a fast, effective and fun way, to probe you as one comes through the Immigration Gate.--Aspro (talk) 17:03, 25 May 2012 (UTC)

Sorry to spoil your fun Aspro, but it seems that the drugs packages are usually swallowed rather than inserted, so you would have to reach in an awfully long way to find them. Alansplodge (talk) 21:34, 25 May 2012 (UTC)

Fun? or are you advancing an argumentum ad ignorantia. Consider the Joe/Jane Doe. Coming back from a vacation/business trip with a little something. Are the Customs going to ignore this just because their amateurs? Will they think “we won't look there!” I have lived for many years near to an international airport.... listened to boring hours of 'shop talk'. Believe me, they don't have to look far at times and they are seldom disappointed. The grin on their faces (I think) is from the satisfaction that they are smarter than the people they given to examine. This article gives shows that smuggling is not a once in a while pastime [7]. Switch off your computer, step out your door and discover life as it actually is. Its different from CSI which is fiction. In that, thet all have manicured nails and what knot. --Aspro (talk) 15:11, 26 May 2012 (UTC)

Calm down.

You said it was "Fun" to anally probe people. He's saying that it's not an effective technique, since a human digestive tract is about twenty feet long. (Thus, spoiling your "fun", in favor of the presumably less-fun x-ray machines.) 71.235.141.252 (talk) 17:25, 26 May 2012 (UTC)

In most cases they detain the suspect until objects inside the body decide to leave naturally, it has been known to take weeks but border officers have patience. MilborneOne (talk) 17:49, 25 May 2012 (UTC)

And how can they know whom to detain? OsmanRF34 (talk) 17:57, 25 May 2012 (UTC)

Airline Flights offer free food. If you're not seen to pig-out in-flight (belly already full) you get detained. --Aspro (talk) 18:33, 25 May 2012 (UTC)

I can only assume this is some poor excuse for a joke :-/ SemanticMantis (talk) 18:42, 25 May 2012 (UTC)

The joke is that most airlines no longer provide food as part of the cost, and if you want any, you have to pay extra, and please have exact change available. It's in the same fantastic tradition as the price of a meal on certain restaurant menus only covering the meat/fish, and if you want any vegetables or salad or bread, you have to order them separately and pay extra. Airlines also charge for choosing the option of using a credit card to pay for the flight, when in most cases there isn't any alternative, and even if there were, it's inconvenient so most people wouldn't use it anyway. What next? Cinemas will be saying your $13 now only covers the previews and you'll have to pay extra to see the film you've come to see? -- ♬ Jack of Oz ♬ ^{[your turn]} 21:06, 25 May 2012 (UTC)

Getting a bit off topic here, but it must be said in all fairness to airline companies that the last time I was offered a free meal on a flight I paid the equivalent of 600€ for a flight from Munich to Athens. These days, the same flight costs less than 100€ - I could maybe dream up a meal that would be worth paying an extra 500€, but Olympic Airways plastic food wasn't in that category -- Ferkelparade π 00:15, 26 May 2012 (UTC)

Detector dogs can smell the contraband even if it's inside a person. 203.27.72.5 (talk) 20:53, 25 May 2012 (UTC)

Citation needed. Alansplodge (talk) 21:08, 26 May 2012 (UTC)

They usually give entrants the option to wait until they've had some specified number of bowel movements that they monitor (imagine applying to that job), or they offer the person an x-ray. Shadowjams (talk) 21:03, 25 May 2012 (UTC)

From TV documentaries I've seen, they look out for people who appear very nervous. The carriers know that if one of the bags bursts inside you, it's "game over". There are other clues - the country where the flight originated, people travelling alone, maybe with little luggage and/or no convincing story about the purpose of their journey. This BBC report says: "Passengers who are suspected of swallowing it (cocaine) are scanned using a full body X-ray machine at the customs terminal. The machine can then detect if the person's stomach contains the small packages." Another report says; "In December, a British man and woman arrived in Britain from Amsterdam after swallowing and stuffing about 500g of heroin. The woman required surgery to remove the drugs after eight days." Alansplodge (talk) 21:07, 25 May 2012 (UTC)

A UK Border Agency report: "Man jailed after swallowing cocaine" says; "Martins Ndubuisi Onkonkwo, aged 36, arrived at Birmingham airport on 18 May 2011 on a flight from Cameroon via Zurich. He was stopped and questioned by officers who suspected that he was smuggling drugs. He was examined using a high-tech internal body scanner which revealed several packages inside his stomach. He was then taken to Solihull hospital where an x-ray confirmed that many packages had been swallowed. Onkonkwo was then taken into custody at Manchester airport where nature was allowed to take its course. He eventually passed 55 pellets weighing 550 grams." Another African man in this report was detained after "officers became suspicious of his reasons for travel, and (he) became nervous when it was suggested that he had swallowed packages." Alansplodge (talk) 21:11, 25 May 2012 (UTC)

Me again. A British newspaper article describes a drug "mule" being detained after his "itinerary has set alarm bells ringing because of his circuitous, expensive route from Venezuela to London. Starting in Caracas, the man travelled to Trinidad’s Port of Spain and on to London, and he was then scheduled to continue to Amsterdam. His ‘holiday’ was supposed to last all of four days. ‘His route is highly unusual and suspicious...’" Alansplodge (talk) 21:30, 25 May 2012 (UTC)

My belief from watching shows like Border Security and Border Patrol is similar to Alansplodge. They rely significantly on intelligence and profiling. Travelling alone or with similar suspicious passengers, concealing details (like people you know) or otherwise being evasive, angry or vague (possibly to ordinary questions), not keeping a consistent story over time, travelling with people you don't seem to really know (they may seperate you and see if your stories are consistent), age, nervousness, coming from or visiting drug supply hotspots (or other suspicious itineraries/travel patterns), buying ticket with cash very recently (and perhaps similarly acquiring passports very recently), low incomes with odd explainations on how they can afford an expensive holiday (even more so if they only intending to stay for a very short time), not knowing anything about the place they are intending to visit, insufficient luggage for the intended stay time, etc. Sometimes they get intel on possible smuggling attempts or receive info from the flightcrew of suspicious passengers. During searching they also take swabs which may pick up drug traces which the passengers could have transferred either from the environment or if they were on the condoms or whatever. Many of these are also possible signs of other things of concern like people who intend to work illegally (also other things like not having enough money to support themselves and bringing CVs). These may single people out for attentions which will either stop or go on depending on whether you continue to raise redflags or satisfy them, or they may also put you in the the category where you're more likely to be subject to a full check regardless. (I believe I've been subject to both in a fashion.)

It's worth considering even for external body concealments while there's a likely additional sign of bulk or awkward clothing and greater chance they will be picked up by a detector dog, they are unlikely to rely on these alone. (Similar to with security before you board, there is a move to fullbody scanners by customs which if done on everyone may make such concealments difficult, but this is new.) Similarly with luggage concealments where there's also X-rays, many customs don't X-ray every piece of luggage. In other words, even in these cases they often have the same starting point, it's just easier to detect later. Note that at least I think in NZ, and possibly Australia, I believe you had/have? the same right to refuse a patdown or strip search by customs to look fo external concealments as you did a X-ray to look for internal concealments. They would need to bring their reasons for review [8] although I presume reviewers are more willing to allow a patdown then an internal Xray.

Nil Einne (talk) 10:19, 26 May 2012 (UTC)

May 26

Catenanes

Would a very long catenane (for instance, a [1,000,000]-catenane) conduct electricity from one end to the other? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 20:36, 26 May 2012 (UTC)

That would depend on the chemical nature of the catenane. Plasmic Physics (talk) 21:01, 26 May 2012 (UTC)

Chemical compounds with Covalent bonds are not electrically conductive. DriveByWire (talk) 21:12, 26 May 2012 (UTC)

Of course they can be, see polythiazyl. Plasmic Physics (talk) 21:27, 26 May 2012 (UTC)

What's so paradoxical about Paleoparadoxia?

Paleoparadoxia translates as "ancient puzzle". Curious if there was a particular reason for it getting that name. The article doesn't seem to mention anything very puzzling about it. the wub "?!" 21:24, 26 May 2012 (UTC)

Reliable sources are hard to come by. An article at about.com says, "Named by a bemused paleontologist after its odd mix of features, Paleoparadoxia (Greek for "ancient puzzle") had a large, horse-like head, a squat, walrus-like trunk, and splayed, inward-curving legs more reminiscent of a prehistoric crocodile than a megafauna mammal." Looie496 (talk) 22:03, 26 May 2012 (UTC)

May 27

Driving speeds and fuel efficiency

This one has been bugging me -- as I recall, one of the rationales behind the late, unlamented 55 MPH national speed limit in the United States was that it was purported to increase fuel efficiency. So far I've not been able to deduce exactly why driving at slower speeds would have an impact on fuel efficiency: Certainly the chemical structure of gasoline has exactly the same potential energy regardless of how fast it's being pumped into the engine, no? So I'm wondering by exactly what physical mechanism higher driving speeds reduce fuel efficiency. Evanh2008 (talk) (contribs) 01:55, 27 May 2012 (UTC)

Really fast cars seen to be built with primarily speed in mind, not fuel efficiency, so they might be thinking that a relatively low speed limit would eliminate those cars, leaving the slower, fuel-efficient cars. (Which doesn't mean they're thinking right—there's no limit on how slowly one can drive a car with a really high top speed.) Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:02, 27 May 2012 (UTC)

Actually, that isn't it at all. Even economy cars can go considerably faster than any speed limit I've ever seen (I got my 1982 Toyota Tercel, a utilitarian ride if there ever was one, well in excess of the top "85" listed on the speedometer. I was probably going about 100). Every car has an optimal speed for which it has a maximum fuel efficiency. Of course, a stopped car, or one barely crawling, has a terrible fuel efficiency, because the engine is doing a lot of running for very little forward motion. However, at the upper end, things like rolling friction and wind resistance become a serious drag (pun intended) on fuel economy. On my current car, a 1999 Ford Escort (again, the textbook definition of a "basic ride") this seems to be at around 70 MPH, but each car is likely different, and perhaps the cars of the 70s and 80s did have peak fuel efficiencies around 55 MPH. Cars have changed considerably since that time. --Jayron32 02:29, 27 May 2012 (UTC)

I actually think cars of that era were designed with higher cruising speeds in mind. However, they weren't very aerodynamic, so the drag at higher speeds would be more of a problem. I doubt if the lower speed limit actually saved any gas, though. In some cases, it wasted gas, as in driving through hilly areas, where you had to ride the brakes down each hill to keep from going over 55, wasting gas and burning brake pads all the way. Then there's the effect that slower cars stay on the road longer, and this causes more traffic jams, which waste gas. StuRat (talk) 02:44, 27 May 2012 (UTC)

Then there's also the (well documented) effect that faster cars have more accidents, and this causes more traffic jams, which waste gas. 203.27.72.5 (talk) 04:05, 27 May 2012 (UTC)

And if a 55 mile per hour speed limit actually made all cars go 55, that would be a valid point. However, you get some doing 55 and others still going 85, which is a recipe for a disaster. StuRat (talk) 04:09, 27 May 2012 (UTC)

In general, your car is using least fuel when the engine revolutions are lowest. Since fuel efficiency is how much fuel you burned for distance covered, the most efficient point is usually where the speed:engine revs ratio is highest. This is normally when you're in top gear with the revs just high enough to prevent the engine from labouring. In my old '88 Nissan Navara this was about 60km/h. In my shiny new Toyota Yaris, I have no idea, because it's an auto so I don't look at the tachometer. 203.27.72.5 (talk) 03:35, 27 May 2012 (UTC)

Kinetic energy goes up quadratically in velocity; if you double your speed, you quadruple your KE. So since the amount of energy needed to increase your speed by 1 unit increases with velocity, the amount of gas needed to get the same effect on velocity increases with velocity. Simplest terms: how much gas you need increase your speed increases with your speed; so, yes, the slower you are going, the better your fuel efficiency, all else being equal. (Going 80 raises your KE by a factor of 16/9 over what is at 50, that's an extra 44% of your KE at 50 than what would be expected.)Phoenixia1177 (talk) 04:18, 27 May 2012 (UTC)

You are assuming the only energy used by a car is to get it up to speed. In reality, that is a very minor portion. Most of the energy is lost to inefficiency, drag, and rolling resistance. If your model was correct, then driving at a constant speed on a level highway with no turns would only require gasoline during the acceleration phase, and you could turn the engine off and cruise for the rest of the trip. Or, to put it another way, you said "all else being equal", but "all else" is nowhere near equal. StuRat (talk) 05:00, 27 May 2012 (UTC)

Why are there no albino horses?

Title says it all… Whoop whoop pull up ^{Bitching Betty | Averted crashes} 01:56, 27 May 2012 (UTC)

There also a breed of horse known as the "Albino Horse" or more specifically the "American Albino Horse", which doesn't have albinism, but is still white. Searches on the internet for Albino Horse usually results in the breed, which gets a bit confusing, because people need to be reminded that Albino Horses aren't actual albinos. See here for the breed. The reason that there aren't any actual albino horses is that the gene that causes albism isn't present in horses, per this article. Searching through google, it appears that some horses have what is called "partial albinism", which is also known as hypomelanism, though none have total albinism, aka amelanism. There appears to be several different genes at work here in several different species, that is there is not a single gene or a single mutation responsible for all forms of albinism in all species, and it appears that horses simply don't have the genetic trait that leads to total albinism in their makeup. --Jayron32 02:23, 27 May 2012 (UTC)

How often should sausages be turned on the BBQ?

My view is that the goal has to be to get enough heat to the middle to cook that the sausage right through. Every time the sausage is turned it has to start the process of getting heat to the middle again, while the bit on top that has just been heated will cool down a bit.

So I feel that sausages should only be turned once.

Is there a good reason for the common practice of turning them many times? HiLo48 (talk) 03:11, 27 May 2012 (UTC)

I think once is sufficient, but don't really see a disadvantage to more than once. One advantage might be grill marks on all sides, if you do maybe 1/4 turn each time, instead of just the top and bottom. StuRat (talk) 04:06, 27 May 2012 (UTC)

It isn't true that "every time the sausage is turned it has to start the process of getting heat to the middle again". If it were true, sausages would be impossible to cook no matter how you did it. Looie496 (talk) 04:28, 27 May 2012 (UTC)

Sorry, I don't see the logic in that post. HiLo48 (talk) 04:32, 27 May 2012 (UTC)

I do:

1) The heat continues to sink in from the side which was previously grilled.

2) The side that was away from the grill is cooler, but not as cold as it was when you started grilling. It will have warmed up considerably from ambient heat in the grill (especially if the lid was closed). Thus, the second side often takes less time. StuRat (talk) 04:52, 27 May 2012 (UTC)

Never before seen color

Is it possible that there exists a color that has never been seen by any human eye? -- 96.55.20.179 (talk) 05:02, 27 May 2012 (UTC)