Wikipedia:Reference desk/Archives/Science/2012 May 23

= 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 ; 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 . You may be interested in the rest of the Animal sexual behaviour article as well. LukeSurlt 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. LukeSurlt 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. &mdash;  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. &mdash;  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.  -- Jayron  32  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. -- Jayron  32  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.  -- Jayron  32  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.  -- Jayron  32  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.  -- Jayron  32  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.  -- Jayron  32  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.  -- Jayron  32  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)
 * 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. LukeSurlt 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. LukeSurlt 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.  -- Jayron  32  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. LukeSurlt 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 ?" . 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   Centri  c  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? -- Jayron  32  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.  -- Jayron  32  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.  -- Jayron  32  21:35, 23 May 2012 (UTC)
 * Here's the science part ... so consecrate: Petrichor contains Terpenoids thus can smell like terpentine re: .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.-Running On Brains (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.  -- Jayron  32  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). -Running On Brains (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.  -- Jayron  32  19:26, 24 May 2012 (UTC)

SELF CHARGING ELECTRICAL CAR
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. -Running On Brains (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  Centri  c  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.-Running On Brains (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)