Wikipedia:Reference desk/Archives/Science/2013 May 24

= May 24 =

Chicken game
I can't seem to find in the article the outcome of both drivers swerving but into each other anyway (a real life situation that many consider when playing). Or even in the case of the bridge scenario both crashing into the ravine. Which made me think of another scenario: both swerving but only one crashing into the ravine. Are these scenarios not considered to simplify the game? Are there other games in which these scenarios are relevant ?68.36.148.100 (talk) 02:43, 24 May 2013 (UTC)
 * The Game Theory scenarios of Chicken are highly simplified. They don't consider every possible outcome, like "swerving and hitting an innocent bystander" or "swerving and clipping the other driver so he crashes but you do fine" or anything else like that.  It really only considers what happens in 4 possibilities:  Both swerve, I swerve, you swerve, and no-one swerves, with the inherent assumption that swerving always leads to safety.  It's used as a model for human behavior, not as a comprehensive analysis of the actual game of chicken.  -- Jayron  32  03:22, 24 May 2013 (UTC)

So you answers are yes and .......? And an actual game of chicken is not a good model of human behavior?68.36.148.100 (talk) 03:25, 24 May 2013 (UTC)
 * It seems reasonable that both drivers would agree in advance to swerve either right or left...and I very much doubt that playing it in a ravine or on a bridge or anything like that ever really happened. But there are obviously cases where people swerved - but to late to avoid some sort of vehicular contact - and the results of that could be anything from "trading paint" to death of both drivers. SteveBaker (talk) 03:58, 24 May 2013 (UTC)
 * Then shouldn't the rules of the game be augmented to include such important details and avoid confusion as to the rules? "OK, I hate your guts but make sure you swerve to the right - deal?" (the adversaries trustingly shake hands) 165.212.189.187 (talk) 13:31, 24 May 2013 (UTC)
 * I suppose it could be, but that's not how Game theory is being invoked here. Game theory is a branch of behavioral sciences that deals with human interactions where two people have a choice on how to behave, and looks at how the perception of the outcome of the choices of the participants feeds back to influence actual choices.  The "Chicken" game is merely the name given to a mathematical model of any scenario where two participants have to make a binary choice, and where the four outcomes are "lose huge-lose huge", "win little-lose little" "lose little-win little" and "tie-tie".  The name of this as "The Chicken Game" in Game Theory is merely a bit of whimsy, as the four outcomes roughly mirror the basic outcomes of the classic game of "Chicken", but that's not the important thing about the game.  It's the four outcomes that makes this a particular "class" of scenarios in Game Theory, it's one of the more famous Game theory models as it comes up again and again (see the article for the "Hawk-dove" model where it looks at the outcomes of deciding between being a "Hawk" (favor war) or a "Dove" (favor peace), and thus can be used to model how politics works in tense situations between states.  These sorts of scenarios help model human behavior because they help to establish what is known as a Nash equilibrium, which attempts to predict what each person in the scenario is likely to do given that each also knows what the other is most likely to do.  The "Chicken" game is an unstable equilibrium, because the only decision that leads to a "win" also leads to "lose huge" exactly 50% of the time, and each participant knows that the other participant knows this as well.  -- Jayron  32  04:00, 24 May 2013 (UTC)

Thanks, I get that "chicken game" is a superficial name for the real theory. So can someone answer my second question? Are there other games where in addition to the four choices there are also the extra ones that I mentioned?165.212.189.187 (talk) 13:13, 24 May 2013 (UTC)
 * Yes, there are game theory style models for much more complex scenarios. For example, in finance, many people use Pareto optimality to demarcate a line of equilibrium outcomes in a high dimensional choice space.  As the scenarios become more complex, and participants have more options and more possible outcomes, it becomes harder to describe in a few simple terms, like "playing chicken."  Nimur (talk) 13:23, 24 May 2013 (UTC)
 * See Spherical cow for the general idea. One should normally make a problem simple to analyse it and only stick in extras if the simple model turns out to be inadequate in some way. Having just the one choice for each person in chicken is adequate for analysing the basic problem. Dmcq (talk) 15:57, 24 May 2013 (UTC)

interference
What is the reason for interfernce112.79.41.16 (talk) 03:33, 24 May 2013 (UTC)?


 * What type interference? Have you read the articles? Plasmic Physics (talk) 03:40, 24 May 2013 (UTC)


 * I presume you're talking about radio and TV interference? In which case you should read our Electromagnetic interference article.


 * Strictly, interference comes about from having two or more transmitters working on the same frequency (or frequencies very close to each other). That can happen (for example) when two radio stations in different parts of the world use the same frequency because they imagine that they are far enough apart for the interference to be bearable...but when optimal weather conditions allow the signal to travel further than usual, you get interference.  But there are many other possibilities.  Most electronics emit some stray unintentional radio waves - and that can interfere with legitimate transmissions.  Sunspots and aurora phenomena can also generate radio waves...microwave ovens, power transmission lines...you name it! SteveBaker (talk) 04:04, 24 May 2013 (UTC)


 * And if you get too close to a radio transmission tower, it can bleed over into other frequencies. ←Baseball Bugs What's up, Doc? carrots→ 04:13, 24 May 2013 (UTC)


 * Also most modern radio and t.v. sets are poor quality receivers, they can't be used to recieve weak signals they are very susceptible to odd order intermodulation effects etc. Good quality radio receivers like the NRD535 are no longer sold. Count Iblis (talk) 13:32, 24 May 2013 (UTC)


 * Much of the interference which bothers radio listeners and television viewers comes from alternating current electric power transmission and distribution lines, along with ham radio transmitters, as well as the make-break of heaters such as those on aquariums, electric blankets, and defective doorbell circuits. I've also seen severe TV interference resulting from two utility ground wires, actually at slightly different potentials relative to earth ground, which were rubbing against one another.  Additional interference (other than distant intentional terrestrial transmissions) might come from lightning.   Edison (talk) 03:21, 25 May 2013 (UTC)

Are there giant rats of about 90cm large?
Just in a novel I see that on Mongolian grassland there is a giant rat of 90cm(3ft) size and can kill a cat. Is this a exaggeration? Or are there other animals of this size but might be recognized as a rat?--Funtkd (talk) 06:55, 24 May 2013 (UTC)


 * We have an article on the subject (of course): Giant rat. The very first entry is the Gambian pouched rat, which states it can grow up to about 90 cm. A specimen of another species, found in 2009, measured 82. Of course, that's nothing compared to the Giant rat of Sumatra. Clarityfiend (talk) 07:27, 24 May 2013 (UTC)
 * Also known as "R.O.U.S. (Rodents of Unusual Size)," or "ROUSes". ←Baseball Bugs What's up, Doc? carrots→ 15:05, 24 May 2013 (UTC)


 * The Capybara is the largest rodent. Adults are over a metre. --Fama Clamosa (talk) 15:44, 24 May 2013 (UTC)


 * There are several species of very large rats out there - there are various "pouched" rats that are that large, but none of them live anywhere near Mongolia. The only Asian giant rats live in Indonesia and New Guinea.  Even if we imagine this might have been some kind of invasive species, those large rats are omnivorous - but the only animals they eat are invertebrates, snails and small crabs.  It doesn't seem likely that they'd kill something the size of a cat - except possibly in self-defense.  Since this was a novel, I think it's safe to assume that the author invented this species to help out the plot.  SteveBaker (talk) 16:01, 24 May 2013 (UTC)
 * Matilda Briggs was not the name of a young woman, Watson, ... It was a ship which is associated with the giant rat of Sumatra, a story for which the world is not yet prepared. Gzuckier (talk) 16:38, 24 May 2013 (UTC)

Can Minkowski's addition to Special Relativity be experimentally supported / disproved?
HOOTmag (talk) 06:59, 24 May 2013 (UTC)


 * It's not clear to me what precisely you're considering to be Minkowski's "addition" to special relativity. Minkowski came up with Minkowski space, which is a convenient mathematical framework in which to express special relativity, but that's not really an "addition" to special relativity in terms of additional physical hypotheses, i.e. any new physical theory, it just provided a convenient mathematical framework in which to express the existing physical theory. So there was nothing new to experimentally test.  Red Act (talk) 14:18, 24 May 2013 (UTC)

How much electric shock can cause permanent tissue damage?
The Milgram experiment used shocks up to 450 volts and says "Although the shocks may be painful, there is no permanent tissue damage". I know that duration and place also matters, but just see what is available.--Funtkd (talk) 07:00, 24 May 2013 (UTC)
 * Wouldn't the amount of amperes be of more importance than the voltage when it comes to causing damage - at least our article on electric shock keeps talking about amperes and not volts when it comes to tissue damage. It does note however that voltages of 500V to 1000V can cause deep burns if applied for some time - however this would be damage due to resitive heating; not due to the electricity itself.
 * The article on static electricity seems to indicate that a human can built up a static charge of 4000V to 35000V, which apart from a unpleasant jolt isn't harmful to us... because the amperage and duration is small. WegianWarrior (talk) 07:51, 24 May 2013 (UTC)
 * It takes a fairly high current density to cause permanent tissue damage, but the amount of current that flows through the tissue depends not only on the voltage, but also on skin resistance. Dry skin reduces the current, but sweating will increase it. At 450 volts there is a possibility that the skin resistance will be broken down (this alone would constitute tissue damage), allowing a much higher than expected current to flow.  The main danger is that the shock current will interfere with the very small currents that control heartbeat.  Even very tiny currents through the heart can cause fibrillation.  I think the claim of no permanent tissue damage would have been a very risky one if the shocks had been real. No insurance company would have covered the experiment with real shocks!    D b f i r s   14:55, 24 May 2013 (UTC)


 * Note there were really NO SHOCKS given to any "Learner" in the experiment. The dial marked "450 volts" etc was a prop, and the "Learner" was not really connected to the apparatus. In psychology experiments of the 1950's and 1960's the source in an actual aversive shock experiment might have  been a source with high voltage and high internal resistance, so that the current was strictly limited to a low current which would not cause physical harm. The Milgram experiment gave the "Teacher" a sample shock from a 45 volt battery, given while the "shock generator" dial was set at 45 volts. The experimental writeup by Milgram does not refer to a current limiting resistor when the sample shock was given,  but it would have been common practice at the time, and without it, a dangerous or fatal shock might have resulted, especially if the current had somehow passed through the heart of the victim. Without a limiting  resistor, the current would have been limited by the slight internal resistance of the battery, the slight resistance of the wires, the resistance of the skin, and the body's internal resistance. Ref Desk has had previous discussions where it was claimed that a far smaller voltage could cause lethal shock if the skin resistance broke down. Edison (talk) 15:08, 24 May 2013 (UTC)
 * That writeup says the sample shocks were delivered to the wrist, presumably meaning both elecrodes were placed there, so chances of interfering with heart or brain would be nil. 45 volts is about what telephone lines run on, I believe, and I routinely rewire my phone lines with bare hands without feeling anything, so there must have been some sort of conducting gel or such used. (The voltage when the phone rings is quite a bit more, however, as I discovered the hard way once). Gzuckier (talk) 16:48, 24 May 2013 (UTC)


 * "The Milgram experiment used shocks up to 450 volts" - NO! That's not true. To be *completely* clear here - there were no actual shocks given to the "learner" in those experiments - it was all just a show to see how far the "teacher" would go, the "learner" was an actor, who was subjected to no shocks whatever.  The statement that no permanent tissue damage would result was just a means to see how far someone would go in causing another person pain if an authority figure told them to...it didn't matter whether it was a true statement or not. SteveBaker (talk) 20:12, 24 May 2013 (UTC)
 * Did you read what I posted at 15:08 before posting your amazing new facts at 20:12? Edison (talk) 03:13, 25 May 2013 (UTC)
 * ( ... or what I assumed in the previous post at 14:55? ) I think real shocks could have been fairly safely performed with a limiting resistor of 50,000 ohms and both contacts on one wrist. The DC shock at 45 volts would have been very mild, whereas at 450 volts DC it would have been quite painful, but the limiting resistor would have prevented burns or breakdown of skin resistance, since the actual voltage across the skin would probably have remained under 100 volts.  The amount of pain depends significantly on the type of contacts used.  Don't try this at home, especially with AC voltages!  The fairground game "pick up the coin" (from the bottom of a metal container of water whilst holding a spoon (connected to a pulsed DC circuit) in your other hand) used to be popular, even at school fairs, but health and safety would not allow it now.    D b f i r s   09:13, 25 May 2013 (UTC)
 * It seems like excessive semantics to speak of a "450 volt" shock that only delivers under 100 volts thanks to an extra resistor in the way. Like saying you could wear rubber gloves and take the shock without harm at all. Wnt (talk) 17:53, 25 May 2013 (UTC)
 * Yes, but that's what happens with a limiting resistor. As stated right at the beginning of the replies, it's the current that determines the pain and the damage.    D b f i r s   18:27, 25 May 2013 (UTC)

Scientific name for a local variety of radish (Choti) grown in Karnali region in Nepal
Choti (चोति) or Choto (चोतो) is a local name for a local variety of radish grown in high mountain areas (>2000 masl) in Karnali region in Nepal. Its photograph is included herewith. Would you please suggest (provide) me full scientific name for this variety of radish. Best regards, Pramod Dahal, Mugu, Nepal — Preceding unsigned comment added by 49.244.70.123 (talk) 09:17, 24 May 2013 (UTC)
 * If it really is a radish, then like all radishes, it's scientific name is Raphanus sativus. Consider that the scientific name of Brassica oleracea covers several common vegetables, including cabbage and cauliflower, which if viewed on one's plate, would not appear to be that closely related, much less the exact same species.  The same is probably true of various radish cultivars.  -- Jayron  32  15:27, 24 May 2013 (UTC)
 * If it's a cultivated variety, then that's probably true. Just like the scientific name for a dog is Canis lupus familiaris - and we use that exact same scientific name for a Great Dane or a Chihuahua because they are of the same species - and it's possible that the same thing is going on here.  It looks like there may be some varietal names out there that might apply: Raphanus sativus longipinnatus seems to be used to refer to the "Daikon" or "Mooli" white radish, which is commonly cultivated throughout East-Asia - but even that seems to come in a bunch of different variations - from globe-shaped to smooth roots to snake-like shapes. SteveBaker (talk)
 * Taxonomy of cultivated plants is particularly problematic. The Species problem, which is already a bit of a conundrum dealing with life forms whose breeding proceeds without human intervention, is a complete nightmare with cultivated plants, orders of magnitude moreso.  I wish I could remember the place I read it (I think it may have been 1493: Uncovering the New World Columbus Created or a related book, but I can't locate it now), there's a real problem with the taxonomy of Potatos.  There are many many hundreds of varieties of potatoes, and the entire group of them is basically like a multidimensional Ring species problem that taxonomists simply can't unravel.  Some place all domesticated potatoes under a single species named Solanum tuberosum, however this paper here (which may have been the original paper behind the source above that I can't remember), notes "Past taxonomic treatments of wild and cultivated potato have differed tremendously among authors with regard to both the number of species recognized and the hypotheses of their interrelationships. In total, there are 494 epithets for wild and 626 epithets for cultivated taxa, including names not validly published. Recent classiﬁcations, however, recognize only about 100 wild species and four cultivated species."  Scientists are still trying to unravel the potato problem; it's a total mess.  At best, taxonomists try to assign a species based on whatever is believed to be the wild variety of the plant being cultivated today, but sometimes it isn't really clear how to do that, as the potato problem shoes, and that leads to all sorts of problems in giving scientific names to cultivated plants, and this includes our Radish above. -- Jayron  32  23:15, 24 May 2013 (UTC)

Breathing
I've heard that people are supposed to breath more with their diaphragm, so that when breathing in, your stomach is bulging and when breathing out it's supposed to flatten or get sucked in even. But sometimes I do it exactly on the contrary. Breathing in, stomach gets sucked in, breathing out, stomach bulges and it feels completely natural. Why is that? My explanation is this. It's less work for the body to do it the "wrong" way, but it results in more shallow breathing. What do you think? — Preceding unsigned comment added by 46.107.26.54 (talk) 12:52, 24 May 2013 (UTC)
 * In my Tai Chi class last night we practiced three different forms of 'breathing'. The one you are describing is referred to as 'reverse breathing'.  It isn't wrong.  For one thing it is the one used for breathing while exerting yourself.  The most important thing about breathing is don't worry about it too much.  RJFJR (talk) 19:52, 24 May 2013 (UTC)
 * In fact we have an article Reverse breathing. RJFJR (talk) 19:53, 24 May 2013 (UTC)

Smallest living being able to learn?
Which one? OsmanRF34 (talk) 19:04, 24 May 2013 (UTC)
 * There is quite a bit of evidence that single-celled protozoa can learn some simple responses. To get much smaller you would have to go to bacteria or archaea -- as far as I know there is no evidence that bacteria can learn in the sense of an individual cell modifying its behavior in response to a teaching signal. Looie496 (talk) 19:29, 24 May 2013 (UTC)


 * Yeah - amoeba have been shown to be capable of simple learning. When temperatures drop, amoeba move more slowly.  So they subjected amoeba to three regularly timed temperature drops - then left the temperature alone.  When the fourth temperature change could be expected to happen, the amoeba slowed down unnecessarily - suggesting that they'd learned the temperature change interval and were actively predicting the next change.


 * But at this incredibly primitive level, it's tough to say what's "learning" and what's just a regular biological mechanism. My bet would be that these creatures have a biological clock that predicts temperature variations on a day/night cycle - and that there is a means for this cycle to be adjusted for different day lengths over the year.  This experiment could easily provoke that mechanism into adjusting it's natural diurnal cycle to the time delay in the experimental setup.  Technically, that's "learning" in that the creature changes it's future behavior based on past experience - but there are clearly inanimate objects that can do similar tricks.


 * SteveBaker (talk) 20:04, 24 May 2013 (UTC)
 * Really!? What inanimate object are you talking about? Dauto (talk) 13:52, 25 May 2013 (UTC)
 * My computer has learned to delete junk mail based on observing my reaction to getting it. My car's computer learns the driving style of it's owner and adapts it's fuel metering system accordingly.  There are plenty of learning systems out there. SteveBaker (talk) 03:45, 26 May 2013 (UTC)
 * You are using the word metaphorically. Conscious organisms can learn totally unexpected associations. The devices you mention have been pre-programmed specifically to respond this way by intelligent programmers. μηδείς (talk) 03:59, 26 May 2013 (UTC)
 * I don't have a reference, but learning is usually considered to have an element of the arbitrary to it. In the case of protozoa reacting to changes in temperature with adaptations to the cold, the reaction is purely physiological and directly related as a natural response to the stimulus.  But a dog learning and reacting to the command "shake" by lifting its paw and putting it in your hand has nothing to do with a physiological adaptation to the effects of the sound /ʃejk/.  The connection between that sound and that act is entirely arbitrary, and hence described as learned. μηδείς (talk) 02:26, 25 May 2013 (UTC)


 * If a child touches something hot or sharp or whatever, and gets hurt by it, and thus stops touching those kinds of things, is that physiological? Or is it learning? ←Baseball Bugs What's up, Doc? carrots→ 15:14, 25 May 2013 (UTC)


 * It would be learning because there's no direct causal link between being burnt and not touching things that look like stoves--it's a psychological association mediated by pain. A purely physiological response would be blistering or scarring. (Obviously everything biological is alos physiological at some level--don't get hung up on that.) μηδείς (talk) 17:00, 25 May 2013 (UTC)


 * Or perhaps life is by definition the ability to learn (i.e. the ability of the system to process information and adapt itself accordingly). Count Iblis (talk) 17:34, 25 May 2013 (UTC)
 * We invent these words and then try to decide whether living things have them or not. It is alleged that a virus is not a living thing. It's apparent that the virus couldn't care less whether we consider it alive or not - it continues to do what it does. ←Baseball Bugs What's up, Doc? carrots→ 19:52, 25 May 2013 (UTC)
 * I agree, and would say that concepts are tools that we design to deal with nature; they do not constrain nature. And our tools can be well or less well-designed. Some tools are objectively better than others. μηδείς (talk) 03:01, 26 May 2013 (UTC)
 * That's called adaptation. If we want to speak metaphorically, that's fine.  But adaptation and learning are perfectly good distinct concepts, and if we say that all adaptation is learning the distinction is lost, and we might as well say there is no such thing as learning, only adaptation. μηδείς (talk) 17:48, 25 May 2013 (UTC)
 * The octopus supposedly displays problem-solving intelligence. Does that mean it's hard-wired, or do they learn from experience? ←Baseball Bugs What's up, Doc? carrots→ 19:49, 25 May 2013 (UTC)
 * I am not the person to ask about octopuses, but basically nervous systems and brains act by connecting sensory inputs with motor outputs and providing ever more sophisticated feedback in higher animals. When the feedback is acquired and when there is no direct physiological association between the input and the output it is called learning.  An exact definition of learning will depend on the context.  What are are called hard-wired behaviors or instincts are better defined as fixed action patterns, such as the unlearned but seemingly intelligent behaviors of wasps that build nests for their young and sting and drag in prey without ever having witnessed another wasp do the same thing.  That is definitely not learning, while trial and error is, as is learning by example and explicit instruction.  I have seen videos of octopuses doing things like unscrewing jars to remove prey, which seems to be trial and error action.  If they get better at it over time it would be learning. μηδείς (talk) 20:58, 25 May 2013 (UTC)
 * So if I'm reading you correctly, that could be called "learning from experience", i.e. figuring out how to do something via trial and error, and then retaining that knowledge when next faced with a similar problem. ←Baseball Bugs What's up, Doc? carrots→ 00:15, 26 May 2013 (UTC)
 * I am trying desperately not to argue in favor of any point since it's synthesis and OR. But if I were to use the phrase learning by experience I would contrast it with instinct on one side (which is not learning) and learning by instruction on the other, which is being told something, rather than figuring it out. Given learning requires memory I would strongly recommend the book On Intelligence] by Jeff Hawknis. μηδείς (talk) 02:59, 26 May 2013 (UTC)

Can you gain more weight than you eat?
A friend of mine who's on a diet, today grabbed a pint (16oz) of Ben & Jerry's double chocolate ice cream. When I mentioned the weight gain, she said "I can afford to gain a pound", because that is the weight of the ice cream. This got me wondering, is it possible to eat something and gain more weight than the weight of the food? — Preceding unsigned comment added by 71.62.100.91 (talk) 20:49, 24 May 2013 (UTC)
 * There are some foods, like olive oil, that are more calorie rich than human fat. In theory eating thse will cause you to gain more weight than the food itself weighs, the balance comes from water during metabolism--Digrpat (talk) 21:24, 24 May 2013 (UTC)
 * Energy and thus mass are conserved. If you ingest one gram of matter, you cannot gain two grams of mass. However, theoretically it could be possible to eat one gram of a substance that somehow grabs another gram of your breathing air and binds it to your body. Practically, I highly doubt that happens in practice. Real foods contain things like water, which are expelled from your body, far outweighing any air-binding properties of the remainder of food molecules. 88.112.41.6 (talk) 21:27, 24 May 2013 (UTC)


 * I had a similar answer but was edit-conflicted. No, your gain in weight is exactly what you ingest (including the air you breathe in) minus what you excrete (and breathe out). So, unless eating all that ice cream makes you excrete less (or become more soporific and breathe out less carbon dioxide), you will not gain more than a pound. Is that any comfort? The point Digrpat is making is relevant if eating one food makes you eat (or, in the case given, drink) more of another. Thincat (talk) 21:50, 24 May 2013 (UTC)


 * Dieters talk of "water weight." If you eat some mass of salt, it could supposedly cause your body to retain water of greater mass than the salt. Naturally, you would also have to drink fluids containing water for this to occur. Edison (talk) 03:08, 25 May 2013 (UTC)


 * It's also possible that you could eat one food item that would facilitate the absorption of nutrients from other food items that would have otherwise not absorbed by the body. Think of it as a catalyser. that would make you gain more weight that the food item itself. Dauto (talk) 13:58, 25 May 2013 (UTC)
 * I don't see how. If you eat a pound of something, at that moment you have gained a pound, no more, no less. The process you describe could cause you to retain that extra weight - but you can't get something from nothing. Your body has a certain total mass. No matter how the molecules recombine at some given moment, your mass is going to stay the same at that moment, right? ←Baseball Bugs What's up, Doc? carrots→ 15:10, 25 May 2013 (UTC)
 * True, but as the comments above suggest, theoretically it is possible to gain a certain amount of mass from the air. For example, we metabolize fat by oxidizing it.  Fat is almost entirely composed of carbon and hydrogen, and oxygen atoms are heavier than either of those, so when a fat molecule is oxidized, its mass (or rather, the net mass of the products) increases significantly.  I can't imagine a scenario where that gain in mass would actually be measurable at the whole-body level, though. Looie496 (talk) 15:24, 25 May 2013 (UTC)
 * You're still ingesting it, though. You weigh more after inhaling than after exhaling, for example. You can absorb things through the skin also. If the question is confined to strictly eating in the usual way, then it could be possible, though it won't happen immediately. It still has to add up to + ingest and - excrete, one way or another. ←Baseball Bugs What's up, Doc? carrots→ 15:31, 25 May 2013 (UTC)


 * Hey bugs, nobody is claiming that mass is not conserved - duh. What we're claiming is that an item might make you gain weight from other sources. Weight that you might otherwise have not gained. Dauto (talk) 17:03, 25 May 2013 (UTC)
 * The OPs question was about weight, not mass. I'm a bit disappointed that no one grammarnazied on the difference yet. 93.132.188.84 (talk) 17:30, 25 May 2013 (UTC)
 * Unless someone is planning a trip to the moon, the distinction is moot. -- Jayron  32  19:06, 25 May 2013 (UTC)
 * Quite as moot as any mentioning of mass energy conservation. We lose mass not only by breathing but also by urinating, defecating and sweating. The OPs question cannot be interpreted simply by taking only the intake mass in account but by shifting the balance between intake and general excretion. If someone measures his weight(loss) after doing sports and before replenishing the water loss by drinking some water, that's cheating. If some lank hyperactive person takes some milligrams of some drug that makes him more calm this may shift the balance quite more then the weight of the pill. — Preceding unsigned comment added by 93.132.188.84 (talk) 19:32, 25 May 2013 (UTC)
 * The question is, are we defining drinking as eating? Digrpat answered this question correctly above. μηδείς (talk) 17:51, 25 May 2013 (UTC)
 * For that matter, how about defining inhaling as "eating"? The questioner asks if it's possible to eat a pound of something and gain more than a pound. If you're only taking the eaten item into account, apparently it's possible. But that's also misleading, as it's denying part of the ingest-minus-excrete equation. ←Baseball Bugs What's up, Doc? carrots→ 19:47, 25 May 2013 (UTC)
 * No, inhaling would not be relevant, because the six 02 molecules consumed in the respirative consumption of one sugar molecule are balanced by six exhaled CO2 molecules. μηδείς (talk) 21:09, 25 May 2013 (UTC) Some of the sugar is also converted to water, but the water is produced from the already consumed sugar. (That is, one could potentially gain weight by the reuse of water from sugar respiration being used in later fat metabolism, but that water would be subtracted from the balance of the mass of the already present sugar.  We do not metabolize inhaled hydrogen as such.) μηδείς (talk) 21:09, 25 May 2013 (UTC)
 * You seem to have missed the bit about the fat metabolism rather than sugar. Roughly CH2 + 3/2 O2 → H2O +CO2.  Molecular weight 14 changes to 18 in the body even counting the loss of carbon dioxide.  Perhaps there are other ways to gain weight, absorb water or cosmetics via the skin, dirt and dust in the lung, lead in the form of bullets, lowering air pressure to reduce buoyancy. I don't think these last would be noticeable on the scales though! Graeme Bartlett (talk) 23:08, 25 May 2013 (UTC)
 * I assume you are addressing me, Graeme, but I am not sure, and if so I am not quite sure of your point. Are you suggesting that the water from metabolized fat is retained as body weight? μηδείς (talk) 02:53, 26 May 2013 (UTC)


 * We've strayed a bit from the original question here. There is a great book on dieting called The Hacker's Diet which goes into all of the science of this.


 * There is a wonderfully informative image there: http://www.fourmilab.ch/hackdiet/e4/figures/figure355.png - which is claimed to come from a NASA study. Basically, what goes into a well-balanced person's body each day is:


 * 2.5 lbs of food,
 * 9.2 lbs of water,
 * 1.8 lbs of oxygen.


 * What comes out is:


 * 0.3 lbs of solids (basically, poop),
 * 11 lbs of water (pee, sweat and moisture in your breath),
 * 2.2 lbs of CO2.


 * So 13.5 lbs go in and 13.5 lbs go out again - and by simple conservation laws, you don't gain weight when averaged over the course of the day. But obviously, if you drink a pound of water - then your weight goes up by 1 lb until you pee 1 lb of it back out again...so this can only ever be an average.  Your weight bounces up and down again by 5 to 10 lbs throughout the day.  That 1 lb of ice-cream is hard to track through all of that - but if you ate an extra 1 lb of the stuff every single day, the results would be a steady weight gain.


 * It's instructive to note that more water goes out than comes in. Humans make close to 2 lbs of water a day!


 * Since you really can't not drink when you're thirsty - if you eat some food that requires more water to metabolize it than most other foods do (eg because it contains a lot of salt) or some food that produces less excess water as you digest it - then the amount of pee might drop below 11 lbs and/or the amount of water you find yourself needing to drink to avoid getting too thirsty might increase above 9.2 lbs - and it's fair to say that because you ate that thing you gained more weight than the thing itself weighed.


 * In fact, since we're talking averages here - unless all foods produce exactly the same amounts of excess water and solids - it would be surprising if some were not above the average and others below...so in some sense, eating a pound of one of the below average ones would indeed cause you to gain more than a pound...just because others cause you to lose less and some balance has to be maintained.


 * That said - if you weigh yourself immediately before eating the ice cream and immediately afterwards, your weight gain would be exactly 1lb. That's true for 1 lb of lettuce and for 1 lb of pure salt...but if you follow normal behavior afterwards, it's possible for you to gain either more or less than 1 lb over the following hours as a result of eating it.


 * Now, we can argue silly semantic or philosophical points about whether the weight gain was "caused" by eating the food or because you subsequently felt the need to drink more or because you failed to pee as much...but what our OP is asking is fairly answered as "Yes, it's theoretically possible that eating 1 lb of ice cream would directly or indirectly cause your long-term average weight to go up by more than 1 lb over the following day or so.".


 * But the question I'd offer your friend is this:
 * "If you hadn't eaten that pound of ice cream - would you have eaten a pound of something else instead?"
 * ...that's a critical part of this! I'd guess that after eating 1 lb of ice cream, you'd be less inclined to eat as much in the next meal - in which case your weight gain is highly likely to be much  less than 1 lb.
 * SteveBaker (talk) 03:31, 26 May 2013 (UTC)


 * I am so glad you finally cut through everybody else's silliness, Steve. Unfortunately talking about "food" and averages instead of specific fats or carbs throws the baby out with the bathwater. μηδείς (talk) 04:04, 26 May 2013 (UTC)