Wikipedia:Reference desk/Archives/Science/2012 July 30
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July 30
[edit]Explain how ducks & chickens stay alive without their heads.
[edit]Warning: The videos show slaughter of ducks and chickens for their food. The channel is "TheTimeToHunt," and they are filmed by farm hands who also specialize in hunting. The video about the ducks is also age-restricted. If you don't wish to view the slaughter of farm animals, please don't watch.
As you can see, after the slaughter, their bodies move around without their heads, for a relatively long while. The chicken, particularly, seems to flail around as if in sheer anger, toward the end of its video. (What is it trying to do?)
Also, I believe it seems to bawk furiously, but how would it without its head?
Anyways, without a brain to control bodily movements, how exactly would their bodies move anyhow?
And have there ever been incidences of decapitated human bodies moving around in a similar fashion? How long did the longest post-decapitation movement last? Thanks. --70.179.170.114 (talk) 00:11, 30 July 2012 (UTC)
- Well, http://www.damninteresting.com/lucid-decapitation/ cites some literature on the topic of human decapitation if you're interested in tracking down non-anecdotal information. BigNate37(T) 00:19, 30 July 2012 (UTC)
- (edit conflict) A simple way to think about it is that not all your brains are in your brain. Many basic bodily movements and reflexes — like your instinctual reaction to being burned — are governed by your spinal cord (in the case of being burned, this has an obvious evolutionary advantage — the spinal cord burn reflex is much faster because it skips the brain until after the fact). Presumably many bird motor functions are handled by non-brain nervous connections. As for people, I don't know about bodies moving after decapitation in anything but very uninteresting ways (and the amount of blood lost in decapitating a human would be immense due to the importance of the jugular veins which would kill the body off very quickly), but two things come to mind: 1. brain death, whereby your body can stay quite alive provided that certain basic needs are met for it, despite the upper functions of your brain being decidedly dead; 2. the opposite question, whether a
decapitatedsevered head can survive long outside the body, has been studied. The answer is not long — again, the key factor here being the sudden change in blood pressure and lack of fresh oxygen, which is quickly fatal to humans and probably all animals above a certain mass. --Mr.98 (talk) 00:24, 30 July 2012 (UTC)
- Also, the brain stem is the most vital part of the brain, and is below the rest, so can be left after a "decapitation". In one case, a chicken survived for years with only it's brain stem. StuRat (talk) 00:37, 30 July 2012 (UTC)
Surgeons with serious ego problems have a fetish for killing siamese twins because they figure it looks good on a resume. One such case comes to mind, where the co-joined twin was not fully formed, I can't recall the name of that condition, but it is quite common. One twin had only fully developed down to their neck, and no further. They lived for their whole life dependent upon their sibling for life support, and lived a good life by their own standards, being sentient, emotional, basically everything any generic quadriplegic mute would be. However surgeons always overlook the fact that twins can live quite happily together forever in their mad rush for fame and the spotlight. The child was murdered by the surgeons in the eyes of the local religious leaders and any reasonable human being, and a funeral took place. So as for the brain living without a body, that can go on for quite some time. As for a body living with no brain, I believe the surgeons are still alive today doing this kind of thing.
I haven't watched any videos, but have read about chickens kept alive for a long time spoon fed after their brains were sliced in a particular way. But you can also study brain death. Penyulap ☏ 04:02, 30 Jul 2012 (UTC)
- How is this relevant to the question? Either way, I think you should be careful making those kind of accusations. There are significant medical, ethical and legal questions surrounding the separation of conjoined twins and it is not remotely as simple as you make out. These days, separation is normally done only if both twins stand a good chance of surviving, or if there is a good chance that both will die if they don't separate them (and that at least one will live if they do). Quality of life is not generally a significant concern - what they think about is whether they will live at all. (This was not always true - separations were performed in the past with lives lost where they wouldn't have been today. There will also be some differences from country to country, but I think the basic goal is the same everywhere, there are just differences in judgement.) --Tango (talk) 13:14, 30 July 2012 (UTC)
- And I guess the chicken flails around furiously towards the end of the video to cope with the sudden shooting pain, correct? If it's got nothing to do with that, then why would it flail around instead of trod around the yard like usual? --70.179.170.114 (talk) 20:42, 31 July 2012 (UTC)
- How does flailing around help cope with pain? 203.27.72.5 (talk) 03:46, 1 August 2012 (UTC)
Names of a couple of extremely hazardous chemicals
[edit]Looking at List of extremely hazardous substances, I noticed that one of the entries was Phosphonothioic acid, methyl-,. Wanting to know what it was, I put it into Google and was pointed to Phosphonothioic acid, methyl-, s-(2-(bis(1-methylethyl)amino)ethyl)O-ethyl ester, but I didn't learn anything about the first compound. This prompted a series of questions in my mind:
- What's the significance of ", methyl-," at the end of the first one? Does it have an extra methyl group somewhere? And regardless of why it's included, why is it tacked onto the end with commas and a concluding hyphen?
- All of those nested parentheses on the second one (VX nerve gas) confused me, because I can't remember seeing parentheses in a compound name before. What do they signify? IUPAC discusses compound naming only very quickly and doesn't mention nested parentheses. Nyttend (talk) 01:51, 30 July 2012 (UTC)
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/ee/VX_TransesterProcess.png/220px-VX_TransesterProcess.png)
- If you look at the first intermediate product in the image to the right, it looks like it's analagous to your "phosphonothioic acid, methyl-", and it's called methyl phosphonous dichloride. I think your compound should be written "methyl-phosphonothioic acid" but they wanted to make it appear in alphabetical order next to Phosphonothioic acid, methyl-, s-(2-(bis(1-methylethyl)amino)ethyl)O-ethyl ester. 203.27.72.5 (talk) 02:13, 30 July 2012 (UTC)
- See the Blue Book Online for examples of parenthese in organic compound names with explanations. 203.27.72.5 (talk) 02:29, 30 July 2012 (UTC)
- Let's go through in this case. 1-methylethyl means that you have a side-chain of the molecule with two carbons (ethyl) with a one-carbon branch from the root (1) carbon. AKA isopropyl (note that the "diisopropylamino" version of the name handles the same thing with far fewer parentheses). bis means you have two of them attached to one spot. That spot is the 2-position of a different ethyl, to which they are attached via an amino, i.e. a nitrogen. If we momentarily chop off the nitrogen and all attached to it, what's left is phosphonothioic acid labelled according to the three different bits coming off of it - the 1-methyl, the S-(2-ethyl), and the O-ethyl ester. (Which O isn't specified, because the two would be mirror images; the formula as written is racemic) I'm not actually sure why it's 1-methyl and not "P-methyl", or if they're going to use a 1 for phosphorus, why the O and S don't have standard numbered positions also (except that would suck) but that's not how they do it. Wnt (talk) 13:51, 1 August 2012 (UTC)
- See the Blue Book Online for examples of parenthese in organic compound names with explanations. 203.27.72.5 (talk) 02:29, 30 July 2012 (UTC)
- If you look at the first intermediate product in the image to the right, it looks like it's analagous to your "phosphonothioic acid, methyl-", and it's called methyl phosphonous dichloride. I think your compound should be written "methyl-phosphonothioic acid" but they wanted to make it appear in alphabetical order next to Phosphonothioic acid, methyl-, s-(2-(bis(1-methylethyl)amino)ethyl)O-ethyl ester. 203.27.72.5 (talk) 02:13, 30 July 2012 (UTC)
- The list gives the source for its information, http://ehs.uark.edu/DocumentPages/ExtremelyHazardousChemicals.pdf, and a look at that source shows that two of the entries for Phosphonothoic acid variants have been truncated in the table. That particular one should be Phosphonothioic Acid, Methyl-, O-(4-Nitrophenyl) O-Phenyl Ester. Looie496 (talk) 02:15, 30 July 2012 (UTC)
- I find myself wondering if some of these listings are motivated by political rather than toxicological factors, i.e. use as precursors to something, e.g. piperidine and aniline, which don't AFAIK rate as particularly deadly. (Not really sure why aniline rates even by this explanation, actually...) Of course, the list has a particularly heavy emphasis on nerve gasses and precursors thereof. Wnt (talk) 03:22, 30 July 2012 (UTC)
- I don't understand the point of the list at all. It has things as common place as ammonia but neglects things as hazardous as nitroglycerin and TNT. About half of the listed chemicals don't even rank as a High Hazard according to my ChemAlert database. It doesn't list any of the toxic lead compounds, some of which are very hazardous (lead sulfate, nitrate, acetate, bromide, chloride, fluoride, iodide, oxide, thiocyanate, chromate, etc.). And as the amount of red ink on the page testifies, a lot of it is ridiculously obscure. 203.27.72.5 (talk) 04:09, 30 July 2012 (UTC)
- That's a valid point. It should probably be moved to another title, one that reflects its legislated nature. I've been following this section and it wasn't until you made that remark that I opened the article and realized that list is based on some American law. I would have assumed it was based on something more quantitative, or at least something more academically authoritative. BigNate37(T) 04:27, 30 July 2012 (UTC)
- As for piperidine and aniline; piperidine is considered highly hazardous with an LD50 of 30 mg/kg (mouse, ingested) plus high flammability and causes burns; aniline is considered moderately hazardous with an LD50 of 195 mg/kg (dog, ingested), though humans have a much greater tolerance for it (TDLo (ingestion): 3125 mg/kg (child)). It's also a possible carcinogen. 203.27.72.5 (talk) 04:35, 30 July 2012 (UTC)
- That's a valid point. It should probably be moved to another title, one that reflects its legislated nature. I've been following this section and it wasn't until you made that remark that I opened the article and realized that list is based on some American law. I would have assumed it was based on something more quantitative, or at least something more academically authoritative. BigNate37(T) 04:27, 30 July 2012 (UTC)
- I don't understand the point of the list at all. It has things as common place as ammonia but neglects things as hazardous as nitroglycerin and TNT. About half of the listed chemicals don't even rank as a High Hazard according to my ChemAlert database. It doesn't list any of the toxic lead compounds, some of which are very hazardous (lead sulfate, nitrate, acetate, bromide, chloride, fluoride, iodide, oxide, thiocyanate, chromate, etc.). And as the amount of red ink on the page testifies, a lot of it is ridiculously obscure. 203.27.72.5 (talk) 04:09, 30 July 2012 (UTC)
- I find myself wondering if some of these listings are motivated by political rather than toxicological factors, i.e. use as precursors to something, e.g. piperidine and aniline, which don't AFAIK rate as particularly deadly. (Not really sure why aniline rates even by this explanation, actually...) Of course, the list has a particularly heavy emphasis on nerve gasses and precursors thereof. Wnt (talk) 03:22, 30 July 2012 (UTC)
If you're still interested in finding out about methylphosphonothioic acid, the PubChem article might be what you're looking for. 203.27.72.5 (talk) 05:15, 30 July 2012 (UTC)
- The answer to this puzzle is actually pretty banal. Those chemicals are there because they appear explicitly in the text of the Emergency Planning and Community Right-to-Know Act, which requires them to be handled in a specific way. Looie496 (talk) 05:19, 30 July 2012 (UTC)
- It's not even a puzzle, it's explicitly stated in the first two sentences of the page! One could certainly propose renaming it to a more clear title, but you can't say the page itself is at all unclear about the listing/inclusion criteria. DMacks (talk) 05:28, 30 July 2012 (UTC)
- My problem wasn't so much with the article, but rather with the list as written by the legislators. Why would you title the list "extemely hazardous substances" when some of the things aren't really that hazardous? Why does the list name some very obscure substances while totally missing out more common and much more dangerous ones? Presumably, other legislation will refer to this list for various purposes. It seems like this list ought to a least be named in a way that makes it a bit clearer what exactly it lists, and better would be word or two as to the criteria for inclusion. 203.27.72.5 (talk) 06:01, 30 July 2012 (UTC)
- Actually the current list is managed by the EPA through the CFR. I'm not looking at the text of the original bill... but even when congress itself writes technical lists like this there's usually input from committees and relevant science. I'm sure they have their own internal criteria for what goes on the list at the EPA. Shadowjams (talk) 09:00, 30 July 2012 (UTC)
- Other agencies and other countries may have different priorities and different lists (yes yes, risk knows no language, but priorities do vary in reality). We shouldn't have an article which presents the EPA's list as though it's a global or agency-independent list of the most hazardous substances. A list which drew together items from different sources might be better; either that or rename the article. No? bobrayner (talk) 12:49, 31 July 2012 (UTC)
- Actually the current list is managed by the EPA through the CFR. I'm not looking at the text of the original bill... but even when congress itself writes technical lists like this there's usually input from committees and relevant science. I'm sure they have their own internal criteria for what goes on the list at the EPA. Shadowjams (talk) 09:00, 30 July 2012 (UTC)
- My problem wasn't so much with the article, but rather with the list as written by the legislators. Why would you title the list "extemely hazardous substances" when some of the things aren't really that hazardous? Why does the list name some very obscure substances while totally missing out more common and much more dangerous ones? Presumably, other legislation will refer to this list for various purposes. It seems like this list ought to a least be named in a way that makes it a bit clearer what exactly it lists, and better would be word or two as to the criteria for inclusion. 203.27.72.5 (talk) 06:01, 30 July 2012 (UTC)
- It's not even a puzzle, it's explicitly stated in the first two sentences of the page! One could certainly propose renaming it to a more clear title, but you can't say the page itself is at all unclear about the listing/inclusion criteria. DMacks (talk) 05:28, 30 July 2012 (UTC)
- The answer to this puzzle is actually pretty banal. Those chemicals are there because they appear explicitly in the text of the Emergency Planning and Community Right-to-Know Act, which requires them to be handled in a specific way. Looie496 (talk) 05:19, 30 July 2012 (UTC)
Sustainable athletics
[edit]Watching the Olympics, it seems like it's more often than not that the athletes are trying to recover from some injury - ACL tear, Achilles tear, etc. Often they're going in with visible signs of injury - it's amazing how many of the volleyball players have two fingers taped together for some reason, for example. Question: is it possible, if people wanted, to arrange the competition not to be a bloodsport, to come up with a way to design things so that the athletes have a lower lifetime risk of injury? Is anyone trying to do that practically? Wnt (talk) 03:50, 30 July 2012 (UTC)
- As an athletic trainer of some years, I can tell you that many tapings are preventative. Many healthy football and basketball players get wrists and ankles taped before each game. Much like compression stockings and compression sportswear, this tape tension applied to joints can give the muscles a tighter "skin" in which to operate; this has the effect of preventing injuries. In the case of volleyball players, multiple fingers are taped together because the paired taping protects the fingers without impairing control of the ball surface. The tape itself can have a positive effect on ball contact. Boxers use a specific taping/wrapping technique which prevents injury of the hands despite constant pounding. Often athletes of Olympic caliber are pressing the body to feats few can achieve. Occasional injuries are often unavoidable. The use of compression taping is one legal and practical method of preventing injuries which otherwise might occur. BusterD (talk) 05:01, 30 July 2012 (UTC)
- Well, they could wear protective gear, like helmets and pads, but who would want to watch a gymnast wearing all that ? They could add more springiness to the ground or equipment, but any substantial change like this makes comparison of new records with old records difficult. StuRat (talk) 08:29, 30 July 2012 (UTC)
- That doesn't help. Statistics show that injuries don't change when protective gear is introduced. People just take more risks. --Tango (talk) 13:18, 30 July 2012 (UTC)
- I'd like to see those statistics. If true, why do American football players wear so much of it ? StuRat (talk) 19:48, 30 July 2012 (UTC)
- Because it's a spectator sport and the crowd loves to see the players take risks....and to see them not pay off. 203.27.72.5 (talk) 19:59, 30 July 2012 (UTC)
- No. Atheletes will always push themselves to the limits in order to maximise their performance. When you do that, there is always a risk that you will go slightly beyond your limits and injure yourself. --Tango (talk) 13:18, 30 July 2012 (UTC)
- Malcolm Gladwell wrote an interesting portrait of a long-distance runner in the New Yorker recently. Basically this guy is one of the best in the world because he can disconnect the part of him that says, "hey, you are at your limit" and will more or less run until he is very nearly dead. He's almost died on numerous occasions. That seems to be what it takes to be one of the great athletes. I'll pass, personally... --Mr.98 (talk) 14:16, 30 July 2012 (UTC)
- In most sports, people are working constantly to better protect players, through rule changes, education and training, better equipment, more severe punishments for offenders, etc, particularly in more dangerous sports like American football[1][2]. I'm unclear if the question is asking specifically about rules to protect volleyball players, but even in volleyball there have been efforts to improve the safety of volleyball players[3][4]. --Colapeninsula (talk) 16:18, 30 July 2012 (UTC)
- That first link is remarkable - not being a sports fan, I didn't have any idea the rules had been changed much for this purpose, let alone so often! It's interesting. Though the page doesn't really say how much all this accomplished. Wnt (talk) 02:37, 31 July 2012 (UTC)
- There can also be superstition around various kinds of tape or special garment; athletes may believe that it helps their performance even if there's no solid evidence to support this belief. Of course, a placebo can still cause a real performance improvement - and something which looks more drastic and medical may have a bigger placebo effect. I don't know whether power bracelet type stuff is allowed in olympic competition (it might be banned for advertising rather than performance-enhancing reasons) but that kind of thing is very popular in various sports. So, some of the visible stuff you see might not be a way of repairing an existing injury, or preventing a future injury, but simply a lucky rabbit's foot.
- Also, there will be some observation bias because these athletes are in the spotlight and generally wearing uniform garments which don't cover all their bodies, so anything on their skin will really catch the eye. Sometimes it's just a bit of tape; no biggie. I used to tape my toes to reduce chafing when I trained intensively; chafing from a single event wouldn't be a crisis, but the cumulative effect would be uncomfortable, and tape is cheap. bobrayner (talk) 12:45, 31 July 2012 (UTC)
- That first link is remarkable - not being a sports fan, I didn't have any idea the rules had been changed much for this purpose, let alone so often! It's interesting. Though the page doesn't really say how much all this accomplished. Wnt (talk) 02:37, 31 July 2012 (UTC)
- I have concluded that the more/better the pading and protective gear in american football the more numerous and severe the injuries based on observing the helmet to helmet and body charging especially when you can support the helmet with the shoulder pads so that there is almost no risk of damage to tackler from a spear-type tackle. Rugby has just as much if not more contact and they seem to have the same injury rate. When you don't have all the protection you reconsider how bezerk you will go on the opponent.165.212.189.187 (talk) 13:42, 31 July 2012 (UTC)
Rough food
[edit]While reading the article Halitosis, I found a term rough food in Management section under point 2. Can you provide me some examples of rough food? Sunny Singh (DAV) (talk) 13:55, 30 July 2012 (UTC)
- It would seem that this refers to the texture of the food, so maybe toast or cereals. I conclude this because the section refers to the scraping action on the back of the throat. --TammyMoet (talk) 14:24, 30 July 2012 (UTC)
- See "Roughage" (—> "Dietary fiber") and wikt:roughage.
- —Wavelength (talk) 20:58, 30 July 2012 (UTC)
Energy density of springs and the like
[edit]What is the energy density of springs, elastics and other mechanical devices for the storage of energy? OsmanRF34 (talk) 17:13, 30 July 2012 (UTC)
Please do your own homework.
- Welcome to Wikipedia. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know.
- We have an entire section in our article on Hooke's law - the thermodynamics of elastic materials. However, in most basic physics texts, you'll see this question come up as a standard example problem for calculating conservative work. Depending on what you're doing, you may be able to get by with simple algebra. Nimur (talk) 18:03, 30 July 2012 (UTC)
Human interaction
[edit]Often a male assumes that if a female smiles at them a lot, then the female is attracted to the male. However in human interaction, the majority of people will smile after making eye contact regardless of gender. So why do so many males have this false predisposition. 176.250.151.7 (talk) 18:49, 30 July 2012 (UTC)
- Wishful thinking. thx1138 (talk) 19:09, 30 July 2012 (UTC)
- It depends on the context. If the receptionist smiles at you, you understand it's just her job. If a woman sitting at the bar keeps looking at you and smiling, it means she is attracted to you, or you are funny looking. :-) StuRat (talk) 19:52, 30 July 2012 (UTC)
- True but other than a bar, generally most people will smile, unless they are in a bad mood. I think smiling is more of a friendly gesture than one that suggests attraction. 176.250.151.7 (talk) 20:22, 30 July 2012 (UTC)
- It's more the eye contact than the smile. A woman who doesn't want attention from a man will carefully avoid making eye contact with him. Looie496 (talk) 20:33, 30 July 2012 (UTC)
- (edit conflict) Most people can tell the difference between an initial eye-contact followed by a friendly smile, and repeated non-accidental eye-contact (with or without the smile) that indicates special interest of some kind -- not necessarily sexual, but usually taken to be, especially in a bar. Most females make similar assumptions. Dbfirs 20:35, 30 July 2012 (UTC)
- This is very much a cultural phenomenon. I remember when I was living in (the former East) Germany, the people there thought Americans were strange because they always smile during general interaction. They didn't find it unpleasant, just odd. Javanese that live in Bali often point out how Balinese people never smile, but foreign tourists there often talk about the glowing receptions they receive from Balinese everywhere they go. How men interpret the smiles they receive from women is entirely dependent on their own background, experiences and predispositions. 203.27.72.5 (talk) 22:50, 30 July 2012 (UTC)
- If the male assumes the smiling female is smiling at him because she is attracted to him, and he is wrong, then he might end up suffering some social embarassment, but no other negative consequences. If, on the other hand, he is right, he might end up mating with her and producing offspring. If the male does not assume the female is attracted to him, then whether she actually is or not, he will not be mating and producing offspring with her. Therefore, natural selection favors males who assume that smiling females are attracted to them, since there is very little cost to him being wrong and much to gain if he is right, so the answer to your question "why do so many males have this false predisposition" is evolution. —SeekingAnswers (reply) 01:34, 31 July 2012 (UTC)
- Except that "some social embarrassment" can mean "comes off as that creepy guy who doesn't read body language or respect boundaries, and treats the slightest friendliness as a sign of sexual attraction: alarming" which can strongly negatively affect future prospects. Even if you're assuming the usual strange world proposed by the typical evolutionary psychologist, it is likely to get the guy beaten up by the men that the women are actually attracted to, and possibly shunned. See also: Schroedinger's rapist, which should really be required reading for all pleasant but slightly awkward men who are attracted to women [5]. 86.161.208.94 (talk) 14:33, 31 July 2012 (UTC)
- There must indeed be cultural differences between regions if Looie496 is correct in his region. I (an Australian male) find that virtually all females smile and look me in the eye - its just natural friendliness and means nothing. I can normally distinguish without any difficulty or even needing to think about it, three situations: (1) Smiling, eye contact, & general friendliness as part of their job, cf StuRat's receptionists, (2) Smiling etc in just being friendly, eg neighbors, someone met while waiting for a train, and the like, and (3) Smiling etc as part of sexual attraction. I don't go on smiles or eye contact - I go on body language and what she does. For example, if she leans forward to you while talking, it may mean she wants you. If you notice that she's slighly (or more than slightly) more vivacious with you than with other males, that is a strong hint she wants you. If she laughs at your weak jokes, that's a good sign. If she fiddles with her clothing, or asks you about her clothing, that's a strong sign. If you pay her a compliment (eg "that dress looks good on you") and she just says "thank you", she's just friendly - but if she responds extra brightly and straightens her back or rotates, that's a good sign. But just a smile, no matter how warm - means nothing. Eye contact - means nothing.
- I think SeekingAnswers is on very shaky ground in asserting males taking friendly smiles as come-ons is due to evolution. In the "cave-man" days, folk lived in small groups and tribes. In such cases, specialisation was most desirable (some made good spear points, others good at spearing animals, still others good at first aid & herbal remedies etc), teamwork essential, and no-one could survive on their own. So friendship and bonding with all tribe members was essential, and distinct from sexual pairings to raise children. A male who imposes himself on a female that doesn't want him has always been a disruptive thing that threatens the team/tribe. This means that evolution may have meant some pressure against propagating males who misread the friendship of females.
- So, what's the answer to the OP's question? It assumes that many males do misread - is this true? If it is, maybe its social inexperience. Perhaps some males haven't found the right girl yet, and have lowered their filtering criteria. Perhaps an artifact of modern western living, which does not involve small tribes. Or chaps who went to all-boy schools and not co-ed schools. Some males spend their early working life in jobs where they don't have any female work-mates. Those that do can practice their social skills.
- Wickwack124.178.41.15 (talk) 02:59, 31 July 2012 (UTC)
7 billion pieces of paper
[edit](This topic could possibly be posted to the Mathematics of Entertainment desk, but since it involves applied math and possibly the behavior of falling objects I've chosen Science.)
After Team GB entered the stadium during the Olympic opening ceremony, the commentators (both BBC and NBC) claimed that 7 billion pieces of paper were released. I presume this figure was part of the press package. Starting with an conservative estimate of one square inch per slip (say 1/2 inch by 2 inches), 144 slips per square foot, and a rough interior stadium area of 500,000 square feet, I calculate that the resulting accumulation would be on the order of 100 slips deep. The actual results appeared to be only fractional coverage of the track and other areas of the stadium. Am I missing something or has the LOCOG stretched reality a bit? -- Tom N (tcncv) talk/contrib 18:50, 30 July 2012 (UTC)
- In case anyone wonders whether you misheard billion for million, that 7 billion number is reiterated by The Telegraph, Dallas Morning news, and ESPN - the wording of each so similar it does sound like it's from the same source. Each says the pieces were "tiny" but not how big. One thing we do know - they were all dropped from a single helicopter. This says the paper-drop copter was an AgustaWestland AW101, which says it can take an internal cargo of about 3000 kg or an external (hooked) cargo of about 5500 kg; I can't find a photo of the drop (showing the helicopter) so lets run with 5500 kg. I'm too busy to do the arithmetic, but if you take that and paper density you can figure out the area of paper (given different candidate paper densities) that it would cover, and so how big a 7 billionth of that would be. Given that it's just one helicoper and not an armada of them, I'd guess the fragment size is of the order of 1 square mm. -- Finlay McWalterჷTalk 19:47, 30 July 2012 (UTC)
- That 7 billion sounded too high to me, too, at the time. I don't think a square millimeter would work, it would just look like you were dropping powder on the field from a camera far away. You want it large enough so you can see individual flashes as each piece turns into and out of the light, from any camera in the stadium. StuRat (talk) 19:56, 30 July 2012 (UTC)
- Standard office paper is 80g/m2 - I would expect thin confetti to be half that (or even less). A m2 has a million mm2. Since the 7 billion slips of paper represent the 7 billion people on earth, we talk about a short scale billion - i.e. a thousand million. 40 g times 7000 is only 280 kg, so the paper slips can be up to about 20 mm2 without too much trouble. --Stephan Schulz (talk) 20:03, 30 July 2012 (UTC)
- That 7 billion sounded too high to me, too, at the time. I don't think a square millimeter would work, it would just look like you were dropping powder on the field from a camera far away. You want it large enough so you can see individual flashes as each piece turns into and out of the light, from any camera in the stadium. StuRat (talk) 19:56, 30 July 2012 (UTC)
- I think the 7 billion figure was supposed to represent the global human population. As for the paper size, my impression from the video feed (where several slips could be seen momentarily landing on the athletes and stirring around near their feet) was that the slips were roughly finger-sized, much bigger than 20 mm2 - more like in the 1000s of mm2. That would seem to eliminate the possibility of a helicopter drop if these figures are correct. -- Tom N (tcncv) talk/contrib 21:19, 30 July 2012 (UTC)
- I just checked - apparently, one can get paper with as little as 7 g/m2. That gives us another factor of 5 or so compared to my computation, i.e. 100 mm2 per slip, or e.g. 4 mm times 25 mm - still small, but not extremely tiny. --Stephan Schulz (talk) 21:54, 30 July 2012 (UTC)
- I think the 7 billion figure was supposed to represent the global human population. As for the paper size, my impression from the video feed (where several slips could be seen momentarily landing on the athletes and stirring around near their feet) was that the slips were roughly finger-sized, much bigger than 20 mm2 - more like in the 1000s of mm2. That would seem to eliminate the possibility of a helicopter drop if these figures are correct. -- Tom N (tcncv) talk/contrib 21:19, 30 July 2012 (UTC)
- After another look at the video and noting several slips riding the girls behind the British flag bearer, I would put my best guess at 15 mm x 60 mm. Using the 7 g/m2, I get about 44 tonnes of paper. Also a few shots of video appear to show multiple sources, possibly ground-based blowers, rather than a single overhead drop. Back to the end-result - I only see somewhere between 1% and 10% ground coverage, which is about 1/1000 to 1/10000 of what I would expect from 7 billion pieces. Should we call this an extreme case of embellishment or is there some other explanation? -- Tom N (tcncv) talk/contrib 23:36, 30 July 2012 (UTC)
- So far we've just assumed that all the pieces are the same as one another. They could quite reasonably be dropping 100,000 larger ones and the rest be 3mm chads. -- Finlay McWalterჷTalk 23:48, 30 July 2012 (UTC)
- I'd just like point out that so far all answers have assumed that the pieces are of equal size. That is almost certainly wrong and if you assume a broad size distribution all that is essential is that the average is very small for the weight to be signifiantly reduced. With a small average size it's still possible that the particular pieces for which their size can be estimated are from the larger end of the distribution. 203.27.72.5 (talk) 00:23, 31 July 2012 (UTC)
- And interesting point based on the two answers above. Assuming the 7 g/m2, 63 million pieces of paper sized 15 mm x 60 mm would be 396.9 kilograms kilograms. That leaves 5103.1 left of the 5500kg. So the other 6,937,000,000 pieces of paper could be about 736 micrograms each or still ~105 square milimetres each. Nil Einne (talk) 08:29, 31 July 2012 (UTC)
- That would make a plausible theory but for the fact that I see no evidence of a "dusting" of the arena, for which I calculate an expected average depth of about 10 1-cm2 particles over an area 60,000 m2. Confetti of that size would also be evident in people's hair. -- Tom N (tcncv) talk/contrib 13:32, 31 July 2012 (UTC)
- Maybe in keeping with the symbolism of the 7 billion human inhabitants of Earth, a few million priviledged individuals of prominent standing were given a position in the grand ceremony, while the rest were dropped in the garbage out back. 203.27.72.5 (talk) 02:29, 1 August 2012 (UTC)
- Isn't there a difference between US billion and UK billion? Which one is the press release using? There might be another factor of 1000 to account for. RudolfRed (talk) 03:33, 31 July 2012 (UTC)
- As noted by Stephan above, it's short scale (i.e. US) billions. 203.27.72.5 (talk) 04:12, 31 July 2012 (UTC)
- If it was long scale, that would be 7 trillion (short scale), and the people on the field would be buried alive. StuRat (talk) 05:03, 31 July 2012 (UTC)
- Note that as the article mentions, there's little difference any more as the short scale is very rarely used in English (as the article also notes, usage in other languages is more variable). (Also as hinted at by StS the human population of the earth is the same (estimated figure), whatever you call the number.) Nil Einne (talk) 07:42, 31 July 2012 (UTC)
- Don't you mean the long scale is rarely used in English ? StuRat (talk) 08:40, 31 July 2012 (UTC)
- Ooops yes sorry for any confusion. Nil Einne (talk) 09:57, 31 July 2012 (UTC)
Foraging worker ant behavior
[edit]Some questions about foraging worker ant behavior:
- Do foraging worker ants eat any of the food they find while they're out foraging, or do they bring all of it back to the colony first?
- After bringing food back to the colony, do the worker ants eat any of the food, or do they just starve and give the food to other castes like queens, drones, larvae, and pupae?
- If a foraging worker ant is separated from its colony and unable to find its way back, does it attempt to survive on its own, or does it just run around aimlessly looking for the colony until it dies?
—SeekingAnswers (reply) 21:48, 30 July 2012 (UTC)
- In most cases, the foragers do not eat the food directly. As with soldier castes, many of them lack the mouthparts to feed themselves. Helper ants within the colony feed the soldiers and foragers. A good example are the leaf-cutter ants; the foragers are collecting leaves, while the ants eat only the mold grown on those leaves, so it must be processed within the mound before being fed to anyone. Foragers would usually have no way of surviving on its own and would soon starve. Matt Deres (talk) 00:43, 31 July 2012 (UTC)