Wikipedia:Reference desk/Archives/Science/2016 March 20

= March 20 =

Null result of Michelson–Morley experiment extrapolation

 * An experiment only has one outcome. If the interference fringes are projected on a screen, then as the apparatus is rotated the fringes will either shift or not. The motion of the person looking at the screen doesn't matter. (This was something that Einstein understood in his original exposition of relativity; he clearly distinguished observers (who were scientists making observations) from the things they were observing (such as the positions of the hands of clocks). He talked about, for example, "an observer who takes S as his reference frame", meaning a scientist who records times shown on the clocks labeled S when they are coincident with other objects. The scientist's motion is unspecified and irrelevant. Later expositors conflated observers and reference frames, which led to the confusing modern sense of "observer" in special relativity. When you look at an experiment while moving rapidly past it, you are an observer in Einstein's sense, and your reference body is the experiment.) -- BenRG (talk) 08:15, 20 March 2016 (UTC)
 * I don't understand. So any observer is flying with interferometer with closed eyes. When he opens eyes, he stops for a millisecond. It changes nothing. When he stops, he cannot see interference as interferometer moves with speed $$\mathbf u$$.


 * And we cannot imitate such observation (because cannot reach speed 1/4 of Earth). So such observation is completely theoretical, besides unproved. We cannot derive other statements from this unproved.95.134.204.112 (talk) 10:58, 20 March 2016 (UTC)


 * It's an assumption of every physical theory that different people see the same readouts on screens. Screens emit light (even projection screens, by scattering it). That light propagates in all directions and some of it eventually hits the retina of someone's eye. If the screen is showing the number 42, the light encodes those digits and anyone who looks at the screen will see those digits. They may be distorted by aberration, but aberration can't turn Arabic numerals into different Arabic numerals. The same is true of M–M fringes. If you draw lines on the screen where the peaks of the fringes are, then rotate the apparatus, the peaks can't shift relative to the lines for one person and not shift for another. I don't know that it's logically impossible for a radically subjective world like that to exist, but we don't live in it.
 * The objects you see (via light transmitted through vacuum) at any given moment are on your past light cone. The direction of the light cone is determined by the spacetime geometry. There are different light cones for different points of spacetime but not for different states of motion. So the observer will see the same thing on the screen (modulo aberration and redshift) whether or not he stops. -- BenRG (talk) 17:39, 20 March 2016 (UTC)


 * If you are moving with the interferometer, it is in your frame reference. Michelson-Morley would not be able to detect relativistic differences between themselves and the interferometer.  And they didn't.  Someone passing by Michelson-Morley's apparatus near the speed of light would not describe the apparatus as having equal light path distances.  They would describe an apparatus with different length paths.  Lorentz made that up.  Einstein proved it.  Two observers in different frames of references though, will measure the speed of light as being the same and nature will conspire to perturb time, length, and mass to make it the same.  The next tricky part is rotating the Michelson-Morley interferometer as someone passes by.  Oops, we no long have an inertial frame but an accelerating frame of reference.  If the observer is moving fast as it's rotating, it moves into a GR category.  Then you have all sorts of weird observer effects.  --DHeyward (talk) 05:16, 24 March 2016 (UTC)


 * I imagine you have to do some fancy footwork with relativity to make sense out of this. The point isn't really that the numbers on the screen don't change, but that the light really gets the same distance at the same time in any frame of reference.  Even though the distance is changing with the Lorentz contraction and the time is subject to time dilation!  And the number of wavelengths in that stream of light have to remain the same per redshift/blueshift so that you can count up just as many nodes in the pattern wherever you look at it from.  It all has to work out so if you mark out a meter, the light goes exactly that meter in the same time as any other light goes any other meter in that frame of reference (in vacuum, at least) ... no matter what.  But I am not feeling so ambitious as to write out all the mathematics just now. Wnt (talk) 17:44, 21 March 2016 (UTC)
 * Ahh, but Michelson Morley experiments show no red shift or blueshift even though they use the velocity of the earth in one direction and orthogonal paths. The key is that the observer is not moving relative to the apparatus. They measure no dilations of any sort. Only an observer moving relative to the apparatus would see that but they wouldn't describe it as Michelson Morely did.  It would look quite different. We can tell relative motion only, not absolute so all SR effects are measured against other moving frames.  Anything in our inertial frame is constant. --DHeyward (talk) 05:01, 24 March 2016 (UTC)


 * Michelson-Morley experiment was a hypothesis regarding the medium in which electromagnetic waves traveled. We know now that the speed of light in free space is constant. However, it is not constant in dielectric mediums.  It's slower.  Always. Michelson-Morley hypothesized that free space was just another dielectric medium which we all move through.  Light through a prism shows the effect.  They expected to be able to observe our relative movement through this medium. After all, if it was static, an orthogonal apparatus might look like 4 inches of glass in one direction and 2 inches in the orthogonal direction and repeating the experiment 3 months later or simply rotating the apparatus should show our direction.  They failed to detect any medium and light was the same in every direction.  This was confusing since they already knew about dielectric propagation (Maxwells equations basically include free space as a dielectric medium) and failing to find a dielectric of any sort wasn't expected.  The null result is the "null hypothesis" as that was stated within the margin of error, I don't think it's a fringing null (could be wrong as fringing would be the same in in orthogonal directions and Feynman might be having a go at a double entendre.  Had they been correct, they could demonstrate the speed of light varied with our relative motion in the dielectric. What they didn't know was how fast the solar system was moving and whether the speed of the earth's motion around the sun was significant. So they kept trying with more and more sensitive apparatus with the assumption the change in earth velocity was too small.  Sometimes your life's work is only a warning to others. Einsteins photoelectric effect, not relativity, probably threw a bigger monkey wrench in the wave propagation theories when "particle" became part of the theory.  --DHeyward (talk) 04:47, 24 March 2016 (UTC)
 * the Feynman answer lies in that the observer in Michelson morley is not moving relative to the apparatus and sees no difference - no red shift, no blueshift, no speed difference. Zip.  There is no absolute frame of reference, only observer relative motion. --DHeyward (talk) 05:04, 24 March 2016 (UTC)

Dandelion wine
Is it possible to literally make wine (or other fermented beverages) from dandelions? 2601:646:8E01:515D:2D19:E107:8069:6081 (talk) 10:24, 20 March 2016 (UTC)


 * Not without any other ingredients, but it certainly is possible to use them as the main flavour ingredient: see here for example.--Phil Holmes (talk) 11:34, 20 March 2016 (UTC)


 * To make any wine you must have some sugar for the yeasts to convert into alcohol. All plants contain some sugars, and flowers contain some as nectar, so there must be some sugar in dandelion flowers. I suspect the wine would be pretty weak if you didn't add more sugar to the mix. By the way, I wouldn't bother trying. My grandmother used to make it - absolutely disgusting! 109.150.174.93 (talk) 11:59, 20 March 2016 (UTC)


 * Likewise. To make wine one needs fermentable sugars that can be turned in to alcohol. Dandelions (and many other flavouring ingredients in wines)  don't have this but they give their name to them because they are the main flavourant.  Just as absinthe and ouzo did not obtain any of the alcohol from wormwood nor the flavourings use in  ouzo. Just as sloe gin  uses sloes only as a flavourant, in-contrast to malt whisky that actually uses malted barley as a source for the fermentable sugars. So, for  Dandelion Wines etc., ingredients with fermentable sugars need to be added.--Aspro (talk) 12:36, 20 March 2016 (UTC)


 * As you can see from this recipe, the bulk of the fermentable material is derived from grapes in various forms, with the dandelion heads there as an adjunct. --TammyMoet (talk) 13:34, 20 March 2016 (UTC)


 * Since just about any plant matter will ferment, I suppose you could make alcohol out of dandelions alone (hopefully they would get the yeast from the air), but you would need lots of dandelions and would get very little alcohol. Also, it would likely taste horrid. StuRat (talk) 19:03, 20 March 2016 (UTC)


 * So I take all this to mean: YES for dandelion-flavored wine, and NO for wine from dandelions alone? Thanks, everyone! 2601:646:8E01:515D:E082:2C68:8C6B:47A9 (talk) 23:24, 20 March 2016 (UTC)


 * As for fermented beverages that are not wine, see dandelion and burdock which (in its traditional form) is a root beer. The extra sugar would traditionally be black treacle (AKA molasses) or golden syrup. You normally include more burdock than dandelion (this recipe uses 150 g burdock root to 50 g dandelion root), but I suppose you could use dandelion root alone - but these are very bitter. Smurrayinchester 09:50, 21 March 2016 (UTC)

cultural acceptance of homosexuality lead to its evolutionary demise??
if homosexuality is maladaptive as far as evolutionary theory (as article suggests..where the only criteria for success is passing on one's genes) then will it die off completely if homosexual lifestyle becomes fully culturally accepted...have the genes continued primarily because homosexuals felt pressure culturally to marry/have heterosexual sex relationships, thereby passing on their genes???? the articles suggests science views it as genetic...and that science is trying to figure if some 'homosexual genes' are beneficial to heterosexual reproductive success...but even if these genes continued it wouldn't mean the continued existence of homosexuals but the continued existence of heterosexuals with a partial amount of so called 'homosexual genes.'...so could there theoretically be a period of full homosexual acceptance worldwide that lasts a couple centuries and then they disappear from the earth altogether.....or perhaps more interesting...is it discrimination itself that the existence of homosexuality owes itself to...????68.48.241.158 (talk) 13:14, 20 March 2016 (UTC)


 * Please see Homosexuality - Evolutionary perspectives. The Ref. Desk will not provide opinion, prediction or debate beyond the studies cited in the linked article. AllBestFaith (talk) 13:50, 20 March 2016 (UTC)


 * yeah, I read that and 'homosexuality in animals' article (which says there are probably no exclusively homosexual animals)..that's what led to my question...my question is about genetics...is it possible that the genes that lead to "full homosexuality" or an exclusive homosexual lifestyle can continue on if these people are never pressured into heterosexual reproduction, and therefore never participate in it..?? perhaps they would still pop up, but just much more rarely?? 68.48.241.158 (talk) 14:04, 20 March 2016 (UTC)


 * Certainly. If you pick a less emotionally charged human trait (and Sickle cell anemia is my 'go to example' here) - we find an entirely genetic disease - that (without treatment) would be fatal before the age at which reproduction is likely.  Why didn't this gene vanish from the population?  In fact, in certain populations, it's a very common genetic disease.   Well, it turns that you only get the disease if you inherit two copies of the gene.  But if you inherit just one copy, you become much more resistant to malaria than people who don't have the gene at all.  So people with one copy of the gene who live in areas where malaria is common have a pro-/con- situation here.  The presence of one copy of the gene decreases the risk of death due to malaria in early childhood so if you have one copy of the gene, more of your children survive malaria - but if your spouse also has the gene then some of your children may get two copies of the gene and die of anemia.  Evidently (since the gene is still around), the benefits of fewer malaria deaths exceeds the cost of more anemia deaths - so evolution favors keeping it around.  This leaves us with an interesting situation, where if only a few people have a single copy of the gene - then the odds of two people with the gene meeting and having children is very small - and children of a person with one copy are about 50/50 likely to inherit it and get the benefit.  But if the gene were to take over the entire population, then one child in four would die of anemia with only half of children still getting the anti-malaria benefit.  So the system self-regulates to a point where between 10% and 40% of the population carries a single copy of the gene - with the percentage being higher where malaria is most common.


 * So this proves that not all genetic conditions are selected out of the gene pool by evolution - and not all of them take over the entire population. Some have to produce a delicate balance between enough copies of the gene to get the benefit - without sufficient copies to produce a downside.


 * The thing about homosexuality is that it doesn't seem to depend on just one single gene - so it's not so easy to pinpoint. (Although there does seem, to be statistical evidence for a genetic component).  Therefore, if being homosexual is akin to having two copies of the sickle-cell gene (in terms of reduced chances of reproductive success) - then the gene (or more likely, genes-plural) must be increasing the reproductive success of the homosexual person's parents or their siblings in some manner that exceeds the risk of having a homosexual child and therefore no grandchildren.


 * When a single gene is involved (as with sickle cell anemia) it's rather easy for geneticists to figure out what that benefit is. But when there are multiple genes involved, it can be exceedingly difficult to understand the interactions between them - so we very often don't know what the benefits are - but we can be sure that they must be there, or (as our OP suspects) the genes would be selected against and eliminated from the gene pool in just a few generations.


 * It's very tempting to look at the stereotypical traits of gay people and wonder whether those traits would be present and valuable in their parents - but it's a very tricky matter. There is no obvious trait that you'd see by examining sickle-cell anemia victims that would predict the presence of the gene in their parents...and that's a much simpler genetic situation than in homosexuality.


 * Knowing these things, whether cultural acceptance would make a difference is hard to say.  I suppose that cultural pressure to hide ones' homosexuality forces some gay people into heterosexual marriage and a non-zero probability of having children - which would allow these genes to propagate more rapidly than if cultural acceptance had made those marriages less likely.  But that could only adjust the balance because even a reduced (but non-zero) chance of reproducing would apply sufficient evolutionary pressure to eliminate the gene after sufficient time has passed.  Given enough time, evolution can eliminate genes if there is only a tiny downside to them.


 * So, on balance, I doubt that cultural acceptance can make any significant dent in the matter either way. Far more likely is that there are subtle reproductive benefits to people who only have some fraction of the genes involved - and that would continue to maintain the genes in the gene-pool, no matter the cultural changes around homosexuality.


 * SteveBaker (talk) 15:28, 20 March 2016 (UTC)


 * I'm puzzled as to why the OP feels that gay people wouldn't want to have children. I pretty sure that gay people feel the same way about having kids as non-gays. CambridgeBayWeather, Uqaqtuq (talk), Sunasuttuq 00:37, 21 March 2016 (UTC)
 * There are many, many gay people who have children of their own and/or adopt. ←Baseball Bugs What's up, Doc? carrots→ 00:47, 21 March 2016 (UTC)


 * I believe that the OP's assumption is that "out" gay people have fewer children who carry their genes, and thus are less likely to pass on those genes. StuRat (talk) 06:00, 21 March 2016 (UTC)
 * Another page to check out: Biology_and_sexual_orientation. That said, it's a big assumption to assume sexual orientation is the result of heritable genes or alleles. Epigenetics, neurobiology, hormones, etc. have all been suggested as possible casual factors. Further, it is incorrect to assume something must be genetically beneficial to survive natural selection. Rather, a heritable trait must either be selected for (beneficial) or selected against (detrimental), but it's possible to have neutral and vestigial traits.  Eve rgr een Fir  (talk) Please &#123;&#123;re&#125;&#125; 06:07, 21 March 2016 (UTC)


 * As far as homosexual genes being beneficial to reproductive success, here we might look at bonobos, which engage in all kinds of sex, including homosexuality. There it seems to serve a social purpose, by reducing tensions and making war less common than in chimps, thus helping all to survive and pass on their genes.  I don't know if any bonobos are exclusively homosexual, but, if so, that could be explained by Steve's sickle-cell example above, or by helping the whole group to survive, so that bonobos related to them pass on their genes more successfully, even if they themselves don't.   StuRat (talk) 06:06, 21 March 2016 (UTC)


 * it seems then that if there's a requisite genetic component required (even if some environmental requirement too)...then the theoretical full acceptance of homosexual lifestyle over the centuries would have hugely reduced the homosexual population that exists today...perhaps possibly from, say 10% of population, to perhaps less than 1% of population...(obviously the point above about adoption is irrelevant and missing the point...but homosexuals passing on their genes with surrogates or with new technology going forward would be relevant)..but can't find anything along these lines in literature (ie discrimination itself being the mechanism by which the thing discriminated against exists...seems like something an academic could make a reputation on)..but perhaps would be considered way politically incorrect within academia as stating that homosexuality is technically maladaptive within evolutionary theory is probably itself a bit of a no no (I read an article once that suggested the high rate of homosexuality in the priesthood is due to the socially accepted cover it allowed men who had no desire to marry/have heterosexual sex relations.....) 68.48.241.158 (talk) 12:39, 21 March 2016 (UTC)
 * Hypothetically, it could be that there isn't an allele for "homosexuality", but rather an allele for "wanting to have sex with men". Whether that was evolutionarily maladaptive would depend on who inherited it. Iapetus (talk) 13:41, 21 March 2016 (UTC)


 * The argument about social pressure makes perfect sense, except ... other mammals have comparable rates of homosexuality. I am not aware of any explanation of homosexuality rates that makes any sense at all.  Even the fecundity argument falls short, because I can't believe a biological system can't adapt to work differently in men and women, given how many major organs do. Wnt (talk) 11:46, 23 March 2016 (UTC)
 * There are plenty of cases where genes that are advantageous for women but are disadvantages for men (and vice-versa). The genes that produce different kinds of green receptors in the eyes of hunter-gatherer women would allow a group of them to better sort ripe fruit that they've gathered from unripe fruit.  But those genes results in a significant proporition of the the males being red-green colorblind...which isn't great for them - but probably doesn't reduce their hunting skills.  That's great for hunter-gatherers - but fails badly when we're all office workers.


 * Since half of our genes come from a woman and the other half from a man, it makes sense that some of these things will wind up being compromises in which one sex gets a statistical advantage and the other a disadvantage. Ideally, these useful-to-one-sex-only things get confined to the X and Y chromosomes - but useful mutations may not arrive there so conveniently.  In such cases, evolution will very effectively do a hard-nosed statistical calculation of cost vs. benefit and keep or reject those genes based on the overall reproductive rate of the group.  So it's entirely possible for severely disadvantageous genes to remain in the gene pool if they have a small 'upside' for a large enough fraction of all people.  My example of the sickle-cell gene is a classic example of that - even if both parents have the gene, having half of your kids not die of malaria trumps a quarter of them dying of anemia - but only in an area where malaria is very common.  The statistical distribution of those genes follows the places where malaria is (or recently was) common with extreme precision.  SteveBaker (talk) 15:10, 23 March 2016 (UTC)


 * "other mammals have comparable rates of homosexuality..." that's just it...I don't think that's true...apparently exclusively homosexual preference doesn't exist in the animal kingdom...and the primary thing that distinguishes humans from animals is advanced social constructs/pressures...thereby leading (paradoxically) to homosexuality's continuation (ie it is selected out of existence by all lower animals...) possible??68.48.241.158 (talk) 18:33, 23 March 2016 (UTC)


 * Hmmm, I see there's also some self-contradiction in our article Homosexual behavior in animals which says it is rare, but later says it is common in a variety of other species. I haven't looked into this closely but we probably ought to nail that down better.  Still, a high rate in any non-human species pretty well rules out social compulsion - I mean, sheep may be notorious followers, yet I doubt that a hundred years ago they had draconian punishments for gay rams who had to learn to play along at being straight to get by.  I mean, that seems like pretty deep thought for a sheep... or perhaps they are just smarter than to make such nonsense rules to begin with. Wnt (talk) 00:27, 24 March 2016 (UTC)


 * Sounds like it's rare, in general, but common in some other species. Heck, lesbian cows were even useful in determining which other cows were season (they would attempt to mount them).   StuRat (talk) 02:16, 24 March 2016 (UTC)


 * it's discussed in the article but nonetheless seems labeling animals 'homosexual' is extremely misleading in and of itself....it mentions same-sex sex behavior as part of the animals overall repotoire, this makes sense, I suppose...as more or less keeping in practice for reproductive sex among other things...I don't think exclusive homosexual attraction/interest can be observed in the wild (but how would such even be observed??)..though perhaps it exists as a very, very rare anomaly...and it would perhaps exist in humans only as a very, very rare anomaly as well but for social pressures....)...anyway..68.48.241.158 (talk) 16:14, 24 March 2016 (UTC)

Silver polish
Grandma's silverware stored away is dark, tarnished and looks like junk. But when she about to host a formal dinner, she got to work with some stuff in a bottle. After a while, the silverware looked like new again and was white and shiny. Within a few months it turns dark and ugly again. What's the stuff in the bottle? It seems you can't buy this silver polish in local shops anymore. Only things based on pumice power or other abrasives designed to clean saucepans. — Preceding unsigned comment added by 120.145.169.202 (talk) 13:50, 20 March 2016 (UTC)
 * Well, this is 2016. If you can't buy something locally - then search online.  I typed "Buy silver polish" into Google and got a bunch of supermarket links for a half dozen brands - some of which I could get locally.  Also links to people selling the stuff on Amazon.  If you know the particular brand your grandma uses - just Google it with the phrase "buy XXX silver polish" - where "XXX" is whatever she swears by.  Since these kinds of searches use your location information - you'll need to do it for yourself. SteveBaker (talk) 14:02, 20 March 2016 (UTC)
 * Tons of non-abrasive silver polishes, including some which deposit a thin layer of silver on the surface, and some which chemically remove the sulfur which causes the tarnish. Urea salts use to be commonly used to "dip" silver collectible coins, for example. For household silver, Wright's silver polish seems to be a pretty universal choice (not a commercial recommendation here).  For keeping tarnish from re-occurring, and to avoid fingermarks, you might try a microcrystalline wax (used by the British Museum on almost everything from paper and coins to paintings and furniture).  Collect (talk) 14:05, 20 March 2016 (UTC)Collect (talk) 15:02, 20 March 2016 (UTC)
 * I don't know what urea salts do to silver coins, but the rule generally is never to polish collectible coins.  They acquire a valuable "patina" which is removed by the chemicals in the polish. 2.221.197.64 (talk) 14:33, 20 March 2016 (UTC)
 * "Toning" is, at times, and for modern collectible coins, sometimes quite ugly. While grading services try to mark cleaned coins as "cleaned", a coin which then acquires toning (say, by placing in contact with paper containing sulfites for a period of time) is generally more easy to sell than one with "ugly toning".  The urea dip and distilled water rinse does not "polish" the coin, by the way. PCGS states: No matter how the results are achieved, many coins have been improved by judicious cleaning with commercial dips, solvents, or plain soap and water. PCGS grades many coins that have had their surfaces altered by the removal of "problems," perceived or otherwise. The coins it does not grade are the ones altered by adding substances to the surface or altering the surfaces by physical methods. Collect (talk) 15:02, 20 March 2016 (UTC)


 * The key word here is "collectible". Sure, if your goal is to eventually sell the item as a valuable piece of antique silver to a fanatical collector - then not cleaning it is probably a good idea.  However, that's not everyone's goal.  If I wish to actually use grandma's silver tea set for serving tea - then nobody is going to be very happy with a grungy, blackened milk jug.  So you have to clean it - even if doing so will gradually wear away the sharp relief of the design and make it less attractive in the event you ever wanted to sell it.  You don't HAVE to treat antiques as things to be revered, that have to look ugly and be entirely non-functional in order to preserve their value - it's equally valid to use end enjoy them as they were intended to be used so long as you understand that they may depreciate in value as a result.
 * SteveBaker (talk) 14:44, 20 March 2016 (UTC)


 * That’s almost a good point. But the OP states a formal dinner suggesting all the right accoutrements but you mention a silver tea set for serving tea. Silver-tea-sets were once very common and popular amongst the more lower middle classes in Britain.  They where made from Sheffield plate.  A very, very thin  (and thus cheap)  coating of pure silver that was fused to the base alloy – and the very very thin pure silver layer  doesn't turn black so readily. Yet, with only a few decades of polishing it wears away and reviles the base metal. Which is why one only sees them now  on things like the Antiques Roadshow  were the owner  has had locked away in a cardboard an never been used since he inherited it from his greate-late-maided- aunt or whomever.  With a valuation put on it that wont even make dent in his daughter's credit card deficit . Most silver tea set  stuff is lower middle class crap.  Yet, the OP's states that s/he Grandmother uses her silverware. The OP's grandmother sound to me as though she has the real McCoy  – the solid good quality stuff. Which both needs taken care of but enjoyed during  our short sojourn in life. --Aspro (talk) 15:49, 20 March 2016 (UTC)
 * Note my earlier point - that there are polishes which deposit a thin layer of silver, which is what a lot of "antique dealers" do for thin spots on silver-plate .   Further - some patterns may, in fact, be highly sought after, mirabile dictu. Collect (talk) 18:01, 20 March 2016 (UTC)
 * My mother swears by baking soda mixed into a paste. You can also use toothpaste. Another recipe is to put the silver into a bit of aluminium foil in a bowl, add salt and baking soda to the bottom of the bowl, pour on white vinegar to disolve the soda and then cover in boiling water. Leave until cool enough to remove with your fingers and polish with a soft cloth. --TrogWoolley (talk) 14:35, 20 March 2016 (UTC)
 * Toothpaste in general is far too abrasive for silver - it is used, however, for polishing acrylics. Collect (talk) 15:02, 20 March 2016 (UTC)
 * Oh. Don't know where to start on this. Low grade silver will tarnish very quickly and badly but it may be you grandmother is storing it where the is high humidity (i.e., above 40%), (which will occur in more parts of the world). Placing them (after being cleaned) in a sealed plastic bag with some silica gel, may leave the silverware requiring nothing more than a final soft-cloth polish for those special occoations. Remember, every time one cleans silverware  it wears some of it away... and lowers it value. Silver polish and aluminium/backing soda is still on sale everywhere. Just google it. If one-day you are hoping to inherit her cutlery, it may be worth genning up on the expert views. Suggest one starts here: Victoria and Albert Museum Kensington, London, Great Britain. Also, the silverware may be hallmarked, so from that you can find the quality and ascertain if it just gets tarnished from simply little use and bad storage. You may save your Gran quite some time (-especially if it is a silver-service of many forks, knives, spoons, tureens etc.,)  in polishing with needles silver polish, when all it requires is a soft-cloth to bring up the lustre if properly stored.--Aspro (talk) 14:38, 20 March 2016 (UTC)
 * Re: V&A: "Microcrystalline wax is used there routinely - but they also do have a special cellulose nitrate lacquer for silver if tarnishing remains a problem." Collect (talk) 18:09, 20 March 2016 (UTC)


 * Hi 120.145.169.202,
 * After all the advice above you have to use your common sense. If Grandma was keeping these items in a glass display case for view only, then I would say use microcrystalline wax but that is over doing it. For one, the best stuff is a sod to wash off. Hot water and washing up liquid wont do it. Second, small imperfections may cause pitting at that point (i.e., creates a electrolytic cell) which can be created by use. Lacquer, forget it, if the utensils are being used for the purpose they were designed for - pit corrosion again. Now that we (you perhaps too) don't rely on gas lighting from coal gas, there is little sulfur in the air other that from diesel vehicles. So, I would go for the simple practical solution of keeping the sulphur out by purchasing a large  enough  polythene bag to hold them all (including the baize lined case if they are of top quality and are contained in one). Include a silica gel sachet or two to keep out the moister (get a sachet that has a dye indicator to show when it is exhausted), (the dyes may be carcinogenic,  but if  you do not eat them  you'll be OK). If you must, included a sachet or two of an oxygen scavenger to prevent oxidization. Doing more  (in my view) is  a complete over kill. Finally:  This time next year I may be in Western Australia – can I pop round for dinner and I promise to do the washing up afterwards and take out the trash.--Aspro (talk) 19:39, 20 March 2016 (UTC)

Isn't there a clever trick for cleaning silver using electrolysis, which gets the tarnish to hop onto a piece of silver foil? --Dweller (talk) Become old fashioned! 13:01, 21 March 2016 (UTC)


 * BTW, we have an article on Microcrystalline wax. -- 2600:1004:B016:7C7A:5F9:69FF:E30A:CDED (talk) 16:31, 22 March 2016 (UTC)

Pacific Ocean disappearing
When is the Pacific Ocean expected to disappear? — Preceding unsigned comment added by 67.175.112.132 (talk) 16:47, 20 March 2016 (UTC)


 * As the adjoining map indicates, the width of the Pacific is shrinking at a rate of around 2 inches per year. If it kept that up for 300 million years it would eventually narrow to nothing. Most geologists probably don't expect it to disappear, though -- the forces that drive plate motion are so poorly understood that it is essentially impossible to extrapolate more than 50 million years into the future. Looie496 (talk) 17:14, 20 March 2016 (UTC)


 * What about the rise in sea levels increasing the size by drowning low-lying islands?   D b f i r s   20:44, 20 March 2016 (UTC)


 * 1) The rise is sea levels is due to human activity (global warming), so what the sea level will be in 300 million years is anyone's guess.


 * 2) Higher sea levels would delay the closing of the Pacific, but eventually the mountains on both the Americas and Asia/Africa would crunch into each other, if we assume the plate movements stay the same. StuRat (talk) 20:52, 20 March 2016 (UTC)


 * Some concepts for future plate configurations include Amasia, Novopangaea, and Pangea Ultima. The first two of these imagine that most of the Pacific plate is eventually subducted over the next ~200 million years.  The last of these envisions an eventual reversal of current trends that spares much of the Pacific and destroys most of the Atlantic.  To quote Christopher Scotese, these future scenarios are "all pretty much fantasy to start with".  Truth is, we don't really know what is going to happen.  Dragons flight (talk) 20:47, 20 March 2016 (UTC)

Mark Twain noted that the Mississippi River was getting shorter each year - and that it was once a million miles long, and in the span of a few centuries would be only a bit longer than a mile. Extrapolation of such matters does have problems. Collect (talk) 23:23, 20 March 2016 (UTC)
 * Had his prediction been about the Colorado, he would have been onto something. ←Baseball Bugs What's up, Doc? carrots→ 23:59, 20 March 2016 (UTC)


 * Assuming it is the same reference that I know of, Twain was upset by the dams and dredging of the Mississippi River to keep it from moving around. One of the results was that the end delta was shrinking. So, Twain joked that the shrinking would eventually cause the Mississippi to shrink to nothing. 209.149.114.215 (talk) 16:19, 22 March 2016 (UTC)


 * The folks with dwellings on the cliffs which are being undercut by erosion might argue that it's the other way around - that it's the coast that's diappearing. ←Baseball Bugs What's up, Doc? carrots→ 01:24, 24 March 2016 (UTC)

Preparing Hydrogen cyanide without platinum.
I want to make Hydrogen cyanide for private reason at home or somewhere. Platinum is very expensive, I can't buy it so I need a replacement for that. Platinum is a catalyst. I need something cheap alternative. For more information see https://en.m.wikipedia.org/wiki/Hydrogen_cyanide#Production_and_synthesis thanks — Preceding unsigned comment added by 45.79.180.120 (talk) 23:08, 20 March 2016 (UTC)
 * Buy lots of apricot kernels. No further information on such shall be supplied. Collect (talk) 23:20, 20 March 2016 (UTC)
 * I know a couple of syntheses, but before I tell you anything I need to know what you plan to use this stuff FOR! 2601:646:8E01:515D:E082:2C68:8C6B:47A9 (talk) 23:21, 20 March 2016 (UTC)
 * I think it's a little pointless to try to keep someone from finding out how to make cyanide. It's too easy (if you don't sweat efficiency, safety, and quality control), and the information is too available.  I'm not going to support burning books (or gatekeeping access to them) to get rid of dangerous knowledge.  I'm also not going to be the one to answer the question, though. --Trovatore (talk) 23:27, 20 March 2016 (UTC)
 * OP, you should be aware that, even if your ultimate purpose for the cyanide is not criminal, the unlicensed manufacture may be, and if so would expose you to a part of the US Criminal Code that is treated with a singular humorlessness in the post-9/11 world. Someone can probably find links to the specific statute. --Trovatore (talk) 23:50, 20 March 2016 (UTC)
 * The Toxic Substances Control Act of 1976 is probably the most relevant US statute. Tevildo (talk) 00:10, 21 March 2016 (UTC)
 * Hmm, that looks like mainly a matter of business regulation, not something people ordinarily wind up in jail for. I was thinking more of "destructive device"-type laws.  What all was Shannon Richardson charged with?  She actually mailed the ricin, and that was presumably the biggie, but was there any charge just for manufacturing it? --Trovatore (talk) 02:04, 21 March 2016 (UTC)
 * Richardson was convicted of "possessing and producing a biological toxin", contrary to 18 U.S.C. § 175. Cyanide is certainly a toxin (although not necessarily a biological toxin), as defined by 18 U.S.C. § 178. Tevildo (talk) 09:26, 21 March 2016 (UTC)
 * And there have been direct convictions for KCN. It's a chemical weapon covered by treaty and enshrined in various 18 U.S.C places (that's where most of the statutory crimes are outlined.)  10 years for a chemist possessing grams in his kitchen.  Providing material support is undoubtedly a crime as well as a bad idea and I don't think any editor wants to test what the G considers "material support." --DHeyward (talk) 03:59, 23 March 2016 (UTC).
 * You have a ref for that? (I suppose you mean NaCN or KCN?) --Trovatore (talk) 04:15, 23 March 2016 (UTC)
 * Sorry, KCN (fixed). Ref .  --DHeyward And the sidebar pic here is priceless .  Like many things like "weapons of mass destruction" the law applying to civilians is much stricter than treaty.  The OKC bombing was a statutory WMD attack, but is a routine explosive during war.  We drop that size bomb on ISIS without batting an eye.  (talk) 05:12, 23 March 2016 (UTC)
 * That's messed up. He didn't hurt anyone and he wasn't going to, except maybe himself, and he didn't know he'd done anything illegal, except maybe petty theft, and he goes away for eight years???  That's just wrong. --Trovatore (talk) 05:57, 23 March 2016 (UTC)
 * Not really. Fed penalties are generally more severe than state penalties even though it's likely illegal in both state and federal law.  Prosecuting a PhD in chemistry and instructor under federal law is more of a "you should know better and in case any other Chemists get this idea, we will put you away for a long time."  The Orkin high school dropout making his own bug spray probably doesn't merit a fed prosecution.  I suspect a widely available website, like Wikipedia, would be subject to the "let's make an unequivocable example so they don't ever do it again" especially if an editor has both practical knowledge and experience.  Do no harm is a fundamental principal and giving out cyanide formulas would seem counter to that (and the law)  --DHeyward (talk) 07:38, 23 March 2016 (UTC)
 * Yes, really, this is wrong. Morally.  He did no harm and the state had no moral right to do harm to him. --Trovatore (talk) 16:07, 23 March 2016 (UTC)
 * That's not quite how harm works. Or rather that's not quite how society has defined culpability for criminal acts. We arrest drunk drivers all the time before they actually hurt anybody because "negligence" is a culpable mental state for a crime when the person is aware of a substantial and unjustifiable risk to other people.  Making a conscious decision to commit an act that a reasonable person would consider a substantial or unjustifiable risk is a crime.  There are different culpable mental states from negligence to willful malice (like intentional murder) but we don't just let negligence slip by.  A chemist that is familiar with cyanide would have a hard time proving that storing it under his sink in quantities that could kill hundreds of people isn't a risk (and he didn't).  Drunk drivers have the same problem in court but a "negligent" prosecution is quite different than fatal DUI - both are crimes.  Second and third DUI's even without injury face increasing levels of penalty and sometimes culpability.  (Oh, and the  language used in the US Code - "knowingly" is the culpable mental state.  That's a higher standard than negligently and is what would be required element of a successful prosecution).  --DHeyward (talk) 05:50, 24 March 2016 (UTC)
 * And the Statute he violated was 18 U.S. Code § 229 - it shall be unlawful for any person knowingly— (1) to develop, produce, otherwise acquire, transfer directly or indirectly, receive, stockpile, retain, own, possess, or use, or threaten to use, any chemical weapon; or (2) to assist or induce, in any way, any person to violate paragraph (1), or to attempt or conspire to violate paragraph (1). --DHeyward (talk) 05:35, 23 March 2016 (UTC)
 * Which New Jersey landfill are you planning to dump the bodies in? ←Baseball Bugs What's up, Doc? carrots→ 23:58, 20 March 2016 (UTC)


 * Looks like it is Newark, NJ, corner of Market and Broad streets, near McDonald's. --AboutFace 22 (talk) 14:09, 21 March 2016 (UTC)


 * I have to agree with Trovatore that censorship issues are frightening some of us into silence. I actually raised this issue here recently.  The weird thing is that people feel relatively safe to simply add manufacturing instructions to articles - it's a little like the shops in so many cities where they can sell bongs all day long, but if a person comes in and says they want a pipe to smoke marijuana, the store is at risk of losing everything if it sells to him.  So if people resent this kind of worry - and the agents who might make it more relevant to our community - then the proper response is to improve a broad range of encyclopedia articles to make sure that everyone knows the stuff that "you're not supposed to know". Wnt (talk) 18:02, 21 March 2016 (UTC)
 * What "personal use" could someone have for this chemical? ←Baseball Bugs What's up, Doc? carrots→ 20:06, 22 March 2016 (UTC)
 * No, sorry. Not going to happen. This isn't anarchists cookbook and it would be foolish to provide any information beyond what's in the encyclopedia.  --DHeyward (talk) 20:46, 22 March 2016 (UTC)
 * You're right. I just wondered if there is any legitimate "personal use" for this chemical, as opposed to murdering someone. ←Baseball Bugs What's up, Doc? carrots→ 21:05, 22 March 2016 (UTC)
 * Hydrogen cyanide, not so much. Potassium cyanide can be used in the Collodion process (wet-plate photography).  And, of course, for destroying wasps' nests.  Tevildo (talk) 22:49, 22 March 2016 (UTC)
 * Coincidentally, I was just looking over some things I had posted some time ago in another venue, and I found this link, where there is a fascinating bit that recommends washing "dishes" (this seems to be some specialized photographic meaning of the word "dish", and not, I hope, something you would eat off of) with potassium cyanide. There is another letter on the same page about "cyanogen soap".  It seems that mid-19th-century photogs had a thing about using cyanide to get stuff clean.  (My guess is they were trying to remove stray silver, by converting it to soluble silver cyanide, but I'm only guessing.) --Trovatore (talk) 01:25, 23 March 2016 (UTC)
 * Whoops, according to our article, silver cyanide is not soluble. In that case I dunno.  Would be happy to hear informed commentary or even good guesses with good reasons behind them. --Trovatore (talk) 01:31, 23 March 2016 (UTC)
 * Suicide, of course. 78.148.107.251 (talk) 23:22, 22 March 2016 (UTC)
 * Let us know how it works out for you. ←Baseball Bugs What's up, Doc? carrots→ 23:54, 22 March 2016 (UTC)
 * Suicide kits that are a) less painful and b) more easily attainable and c) doesn't kill first responders and neighbors, and are readily available. If you want to check out, go research it.  --DHeyward (talk) 07:57, 23 March 2016 (UTC)
 * In the erstwhile Land of the Free, an older person I know had a little can of potassium cyanide, and would take part of a spoonful and put it on the entrances to yellowjacket nests. The yellowjackets would drop like flies as they came in or out until none were left.  Apparently this was much better performance than the insecticides of the time, which by now are probably also banned for being poisonous.  (At least with cyanide, you know if you walked away OK you don't have to worry ten years later) Wnt (talk) 11:09, 23 March 2016 (UTC)
 * When someone is vague about how they intend to use a toxic substance, it invites scrutiny. ←Baseball Bugs What's up, Doc? carrots→ 22:32, 23 March 2016 (UTC)


 * Why are you all answering a question that clearly requires legal advice? --Wirbelwind( ヴィルヴェルヴィント ) 17:35, 23 March 2016 (UTC)


 * The person asking the question is not asking for legal advice. The issue coming up is whether Refdesk volunteers need legal advice.  Note the talk page thread I linked above, which was closed well before this was asked.  At the time I was suspicious that some agent of some government might be looking to try to make a trumped-up prosecution of Refdesk regulars... this paranoia has not decreased lately.  And however unlikely, it seems orders of magnitude more likely than a genuine criminal let alone a terrorist coming here to ask.  (I say this because Roskomnadzor is after our meth articles, and Dianne Feinstein can't be far behind) Wnt (talk) 00:39, 24 March 2016 (UTC)


 * The last process mentioned in the section you link is a simple way to make hydrogen cyanide. But the required input is an alkali metal cyanide. Graeme Bartlett (talk) 22:20, 23 March 2016 (UTC)