Wikipedia:Reference desk/Archives/Science/2015 December 7

= December 7 =

Relating to heat transfer
Why heat transfers from hot body to cold body without any work positive or negative while the reverse is explained by second law of thermodynamics.150.242.150.130 (talk) 07:37, 7 December 2015 (UTC)


 * You can get a lot of energy from your first example, that's how engines work. See Carnot Cycle for a no doubt convoluted and innaccurate explanation. Note that the carnot efficiency defines the maximum useful work you can get from a given transaction between a hot and cold reservoir, practical designs will always get less, or quite often, none at all.Greglocock (talk) 09:41, 7 December 2015 (UTC)


 * The second law of thermodynamics says a process will occur, without work being done by the surroundings, if entropy increases or remains constant. The flow of heat from a hot body to a cold body causes entropy to increase, and so the flow of heat in this direction occurs spontaneously. Dolphin  ( t ) 10:01, 7 December 2015 (UTC)


 * Think about temperature as being a measure of the speed of motion of atoms - that's pretty much the classical definition. If you imagine a container of fast-moving things (think ping-pong balls bouncing around in a room at high speed) - then imagine opening a door to a room full of very slow moving things.  At the atomic level, this is a picture of a hot object being brought into contact with a cold one.  You can imagine a fast moving ball going through the door and hitting a slower moving one - resulting in the fast one going a bit slower and the slow one going a bit faster.  This happens a lot, so on average, the fast-moving balls wind up going slower, and the slow moving balls go faster - keep this going for long enough and sooner or later, all of the balls are going at the same speed.  Heat moved from the hotter object to the colder one - and continued to do so until the temperatures are equal.


 * For the reverse to be the case, you'd somehow need a slow-moving ball to hit a fast moving one - and as a result, for the slower one to go even slower and the faster one even faster - but that seems very counter-intuitive. You wouldn't expect the fast balls to end up going yet faster and the slow ones to go even slower...and indeed heat doesn't flow from cold objects into hotter ones. SteveBaker (talk) 15:28, 7 December 2015 (UTC)

The analogy is very helpful and understandable on intuitive level.Will →you please elaborately explain by second law and is the word 'spontaneously' in this context( second law) implying  no work??.Books on heat/ thermodynamics leave this as self evident.150.242.150.164 (talk) 17:01, 7 December 2015 (UTC) Thanks Dolphin and Steve.150.242.150.164 (talk) 17:04, 7 December 2015 (UTC)
 * No, I don't believe spontaneously means "no work", I believe it means THAT IS "the work". If you delve much deeper than that, you might reach the Problem of induction. Vespine (talk) 02:41, 8 December 2015 (UTC)

Anyone recognise this insect ?
— Preceding unsigned comment added by Bobatnet (talk • contribs) 08:36, 7 December 2015 (UTC)


 * There are many thousands of varieties of caterpillar, and many hundreds with eye spots. Can you tell us where it was seen?--Shantavira|feed me 09:54, 7 December 2015 (UTC)


 * Saw this in Chandigarh, India on the street with greenery around. Bobatnet (talk) 11:04, 7 December 2015 (UTC)

It looks like the caterpillar of the Oleander Hawk-moth - Daphnis nerii — Preceding unsigned comment added by 86.140.37.142 (talk) 12:46, 7 December 2015 (UTC)
 * Our article: Daphnis nerii. -- ToE 15:59, 7 December 2015 (UTC)

Looks just like a draught excluder to me.Artjo (talk) 21:44, 7 December 2015 (UTC)
 * Don't go calling my girlfriend a "draught excluder" Myles325a (talk) 04:10, 9 December 2015 (UTC)

Trade secrets and labs
If anyone with enough money can order a chemical laboratory analysis of, say, a Coca-Cola sample, the Coca-Cola formula and similar products wouldn't be trade secrets anymore, would they? (provided that the results are published in open access)--93.174.25.12 (talk) 10:51, 7 December 2015 (UTC)
 * It is possible that the laws defining trade secrets would forbid such activity. ←Baseball Bugs What's up, Doc? carrots→ 13:27, 7 December 2015 (UTC)


 * This is an example of reverse engineering (that article also explains the legal issues that can arise). In general, no laws protect trade secrets - if they were protected, there'd be no point getting a patent (the basic idea of a patent is to encourage companies to reveal their secrets in exchange for legal protection). It is possible to reverse engineer foodstuffs; William Poundstone, for example, tested the KFC Original Recipe and found that the "11 secret herbs and spices" are salt, monosodium glutamate and black pepper (although for something like Coca-Cola that contains around a dozen flavouring oils the process of separating them would be long and time consuming). I'd imagine that Pepsi knows exactly what's in Coca-Cola (and vice versa), but there's less value than you think in producing a drink that tastes like Coca-Cola. You probably can't be much cheaper than Coca-Cola (they can charge a premium for the brand, but they also have huge economies of scale – Coca-Cola seems to control a huge chunk of the world's vanilla market, for example, while you would have to go through wholesalers) and you certainly can't have better marketing than Coca-Cola. According to Cola Wars, RC Cola tastes identical to Pepsi Cola, but RC Cola remains a tiny player in the contest because it doesn't have Pepsi's massive multinational backing. Smurrayinchester 14:28, 7 December 2015 (UTC)
 * Huh? The Cola Wars article does not say that Pepsi and RC taste the same. Nor would most people, I think. Also while Poundstone may have claimed that he reverse engineered KFC spices that is no proof that he did so correctly. Flavor profiles are quite complex. Rmhermen (talk) 22:55, 7 December 2015 (UTC)
 * I think Smurrayinchester is thinking of the Pepsi Challenge article, which does make the claim with a ref from 1950. I haven't check the ref and in any case even if it were true in 1950 it may not be now. But one thing to remember is that even if most people can't taste the difference between two products, if there are certain people who are consistently able to tell the difference (even correctly identify two different batches of one and two different batches of the other), this implies that there likely is a difference. A lot of research tends to focus on whether most people are able to tell the difference, which is interesting for numerous reasons, but is actually a lot less useful in trying to determine if there really is a perceptual difference. (Sometimes research looks in to those who are convinced they can tell the difference, but again it doesn't always explore those who appear to have succeeded that well.) Loosely related but is interesting. It suggests, perhaps not surprisingly that many of those tested were able to taste the difference between US and Mexican coke (how much of this is due to the sweetner difference and how much is due to other compositional differences, who knows). And that most of those (they are Americans so probably used to American coke) prefered the taste of American coke, but that some people preferred coke they were told was Mexican coke. There was also a preference for glasses bottles by some. (Although the tests probably aren't that well designed for scientific purposes.) Nil Einne (talk) 02:18, 8 December 2015 (UTC)


 * At least the 1983 version of Original Recipe was those ingredients, the same article you cite notes that a year earlier, Harland Sanders himself noted that this was not his orginal recipe, and even recommended an alternate source for the correct spice blend instead of the KFC corporate blend. And now that 22 years have past, I'm not sure how accurate Poundstones results would be for today's KFC recipe.  Just noting that Poundstone's test was not a) on Harland Sanders actual recipe (the one held in the vault with the 11 vials of the actual spices to be used) or b) guaranteed to still be the recipe used today.  -- Jayron 32 16:11, 7 December 2015 (UTC)
 * I'm with Rmhermen here, I wouldn't even be confident Poundstone results were true for the 1983 version of the official corporate blend. I'm sure he genuinely believed it was true, but it doesn't mean he was right. Even nowadays, I would be cautious about any labratory analysis, let alone a 1983 one. I'm not saying it's impossible but it's easy to screw up. Although at least Poundstone was (if I understand our article correctly), testing the uncooked mix rather than the coating from the chicken. Of course, even if Poundstone results were true for the 1983 corporate version it may be only the US version. KFC already had a resonable international presence in 1983 and I suspect some of these were large enough that the mix was produced locally. Definitely in modern times, most people who claim to have replicated the current recipe use more ingredients. Of course people can be fairly bad at re-producing stuff based on taste tests. Compare for example many of the McDonald's special sauce recipes to that reveal by McDonald's in Canada or the ingredient lists some publish. Although it's possible some of these were based on local versions of the special sauce which were different. And you also get people convinced that the special sauce sold in packets or bottles in Australia, NZ etc is different from which comes on the burgers (well perhaps because of batch difference etc it is, but the bottles/packages are unlikely to be universal bad as many of these people are convinced is the case unless perhaps it's "contamination" from the meat, lettuce etc that they like.). Nil Einne (talk) 01:43, 8 December 2015 (UTC)


 * "No laws protect trade secrets" is not entirely true. There are laws on the books specifically to protect trade secrets (|18 U.S.C. §§1831-1839) - but these are mainly aimed at those obtaining the secret by fraudulent means. That is, it's against the law (over and above things like standard breach of NDAs and breaking-and-entering charges) for an employee at Coca-Cola who has access to the recipe to leak that recipe to someone else, or for someone to break into Coca-Cola's headquarters and steal the recipe. In 2006 there was actually a case about this, where three people were accused of stealing Coke's formula and trying to sell it to Pepsi - Pepsi was actually the one who turned them in . However, as you mention, there's really no such prohibition on reverse engineering the secret formula from legally-obtained sources. In fact, there's a somewhat convincing argument that the original recipe for Coca-Cola is already out there in a publicly available form  - though not necessarily with the tweaks needed for modern ingredient differences. -- 160.129.138.186 (talk) 16:26, 7 December 2015 (UTC)
 * I think your first link is broken; you probably meant to say "18 USC §§1831-1839", also known as 18 USC Chapter 90, PROTECTION OF TRADE SECRETS. It is available online at no cost from the United States GPO, or from the United States House of Representatives webpage; and it is also re-hosted in an unofficial form by the Cornell Legal Information Institute at this corrected URL.
 * Surely there are also many additional state and Federal regulations that pertain to trade secrets.
 * Nimur (talk) 01:24, 8 December 2015 (UTC)
 * My understanding is that there are a number of state laws, but little of much effect on a federal level, though a new federal law is in the pipeline. Though I'm not that knowledgeable on US law, and only know this because of articles on a blog I follow for professional reasons e.g. . MChesterMC (talk) 09:16, 8 December 2015 (UTC)
 * Here's an excerpt from The United States Attorney's Criminal Resource Manual, on 18 U.S.C. § 1831. (Corresponding manuals exist for each of the other sections).  This publication aims to help Government prosecutors understand procedures for successfully trying federal crimes.  For example, in section 3, there are many precedent cases listed and analyzed for review.  I would posit that a law authorizing a 15-year term in Federal prison, that has been successfully tried and yielded previous convictions, is an example of a law with a "significant" effect.  Nimur (talk) 15:48, 8 December 2015 (UTC)
 * And, here is a state law for California: the Uniform Trade Secrets Act, my state's incarnation of the recommendations put forth as the Uniform Trade Secrets Act proposal. Most states have similar laws.  Our article lists several precedent cases tried as violations of state law, or brought as civil suits.  Nimur (talk) 16:23, 8 December 2015 (UTC)
 * I'm skeptical there's such a thing as law. If you annoy a major corporation, you're going to lose everything you have in lawsuits.  It's just a matter of naked power (possibly opposed by "terrorism").  McLibel kind of stuff.  It seems like even in much simpler analyses, like finding human DNA in hot dogs, those making them don't dare say things that don't sound nice. Wnt (talk) 16:34, 9 December 2015 (UTC)


 * Yes, trade secrets are an interesting aspect of intellectual property law, but when it comes to the "secret formulas" of brand-name foods like Coca-Cola and Kentucky Fried Chicken, it's actually a different game (and maybe even a little more interesting).
 * In the case of Coke and KFC, their "secret formulas" are more than the particular recipes for certain ingredients in certain ratios. Much more important is the mythos that those two companies have quite successfully built up around their formulas, and that mythos is, at this point, pretty much untouchable.  Importantly, a key part of the mythos is not just that the formula tastes good, it's that it is secret, that no one can know what it is.
 * Suppose I managed to figure out the exact formula for Coca-Cola. (Doesn't manage how I did it, but do suppose that it's exact, down to as many decimal places as in whatever master copy the Coca-Cola Corporation has stashed away in whatever uber-secure vault they've hypothetically got for theirs.)  Quite aside from anything which trade secret or any other IP law might say, if I go public with my formula, Coca-Cola will simply say, "No, that is not the official formula".  Now, you might say they're lying, but you can never prove it, because they will never ever show you their copy of the formula.  And, in an important sense, my formula is indeed not official, and if I made some and put it in a bottle, it would never be The Real Thing&reg;.  (And if you ran a non-blind taste test, I'm reasonably sure you'd get the statistically significant result that the non-official formula indeed did not taste the same.) —Steve Summit (talk) 16:30, 9 December 2015 (UTC)

Civil engineering
Is civil engineering a mature field with not much scope for advances in research compared to biology or medicine? — Preceding unsigned comment added by 2A02:C7D:B901:CC00:6591:E3B9:275A:A9A4 (talk) 15:29, 7 December 2015 (UTC)
 * Read this. -- Jayron 32 16:07, 7 December 2015 (UTC)

Civil engineering along with any other engineering field, specialize in problem solving and thereofre ay enginnering field tends to keep its scope into it respected field to be able to solve problems as they appear. The field itslef is very mature and has room to grow from and advance through the form of bridges, roads, and many more. Little fact, civil engineers save more people every yea then doctors. This may not seem right but everytime you drive over a bridge you are putting your life into the hands of the civil engineer that apporved the contrution of that bridge and made it possible. — Preceding unsigned comment added by Sgtmaj.avenger (talk • contribs) 19:33, 11 December 2015 (UTC)

cleaning the dye off money
so they started putting that coloured dye in with the money you get from security vans or out of a cash machine, how does it work and how do you clean it off the money and off your hands? Hugo Baptiste (talk) 19:10, 7 December 2015 (UTC)


 * Just robbed a bank, did you ? :-) StuRat (talk) 19:13, 7 December 2015 (UTC)
 * See Dye pack for our article. See a lawyer if you _have_ robbed a bank. Tevildo (talk) 19:34, 7 December 2015 (UTC)


 * You could try returning your ill-gotten gains, and say your older brother made you do it. ←Baseball Bugs What's up, Doc? carrots→ 20:46, 7 December 2015 (UTC)


 * Seriously, in the US, the Treasury Department will replace damaged currency if enough is left of it to prove how much there was. As a volunteer for a disaster recovery charity, this is something I've mentioned to one or two affected families. Jc3s5h (talk) 00:38, 8 December 2015 (UTC)
 * The police will do this for you for free. Just bring yourself and the money to the police station, it is a free service. 175.45.116.66 (talk) 22:28, 7 December 2015 (UTC)


 * There's no need to clean the money, all the banks need to do is show that the dyed mess really is a certain amount of money and it will be destroyed and replaced with nice new notes. Any dye will wear off skin eventually without anything being done even if only by shedding skin cells, I'm sure a bit of rubbing and washing would reduce any marks considerably. Dmcq (talk) 00:08, 8 December 2015 (UTC)


 * The most common dye used is Disperse Red 9, which is apparently "slightly soluble in benzene and carbon tetrachloride" – but these are both pretty toxic chemicals (and I wouldn't be surprised if they also wrecked the actual printing on the notes). Brings a whole new meaning to the phrase money laundering. Smurrayinchester 15:00, 8 December 2015 (UTC)