Wikipedia:Reference desk/Archives/Science/2014 June 1

= June 1 =

Science
Why do scientists perform the exact same experiments over and over to get the exact same results when the results were obvious from the beginning and didn't even require any testing at all? Does the "scientific method" call for this? Rkable5 (talk) 23:55, 31 May 2014 (UTC)
 * Can you give a concrete example of what you're talking about? But otherwise see Scientific method.--Fuhghettaboutit (talk) 23:58, 31 May 2014 (UTC)
 * Scientific method calls for tests that are demonstrably repeatable. A common experience is that critical demonstrations before sceptical peers tend to go wrong. (This is not considering the "protosciences" of Alchemy and Homeopathy in which repetitions of a process are an integral part of the practice.) Some scientific processes e.g. Heavy water must be done at length because the rate of production is small. 84.209.89.214 (talk) 00:10, 1 June 2014 (UTC)


 * If anything, we don't reproduce experiments enough. Please do give some specific examples of the same experiment that has been done many times if you have questions about a certain case. In general, see reproducibility, particularly the bit at ref 11, which shows that many cancer research experiments could not be reproduced. SemanticMantis (talk) 02:03, 1 June 2014 (UTC)


 * Sometimes the obvious isn't, like that a sugar pill won't help a disease -- see placebo effect. Wnt (talk) 03:06, 1 June 2014 (UTC)
 * Unless what you're suffering from is a shortage of sugar. ←Baseball Bugs What's up, Doc? carrots→ 11:38, 1 June 2014 (UTC)


 * One could argue that among the most ancient "experiments" is the theory that the seasons run in cycles that can be measured by the positions of the stars. In a sense, we re-perform that experiment every year. ←Baseball Bugs What's up, Doc? carrots→ 11:38, 1 June 2014 (UTC)


 * ... except it's the position of the sun that determines seasons.   D b f i r s   11:57, 1 June 2014 (UTC)
 * Yes, the rise and fall of the sun during the year is another way to measure that cycle. ←Baseball Bugs What's up, Doc? carrots→ 13:54, 1 June 2014 (UTC)
 * My point was that the ancient civilisations would observe solar time and seasons before becoming aware of Sidereal time, but I agree that both go back many thousands of years.   D b f i r s   09:03, 2 June 2014 (UTC)


 * Students certainly do classic experiments over and over. But researchers generally do not simply do the same experiments over and over, since they must "publish or perish," and journals would refuse to publish simple replications (unless it is a breakthrough experiment and many doubt the result). When I worked in a research lab, the director would often start an experiment by a replication, varying the methods somewhat to eliminate some potential confound he had noted in his or others' earlier experiment, then in later parts of the experiment, vary the conditions further to extend the paradigm. When someone has published some startling new finding, it pays to replicate it, since many such startling findings are irreproducible due to blunders, due to them being statistical flukes, or for other reasons such as fraud. If you run 100 experiments, and the experimental and dependent variables are unrelated, in 5% of the experiments you would expect to find a result which is statistically significant at the .05 probability level. Replication experiments would help sort out which of these were such statistical flukes. One finding alone is usually not enough to establish something, Can it be reproduced at a different lab, using somewhat f\different methods? Is a finding in learning theory using rats replicable with pigeons (or humans?). Do scientists in France get the same results as scientists in Russia (Lysenko).  N rays, discovered by Frence scientist Blondlot,  could be found in France in 1903, but not i other countries. They were not real. Edison (talk) 14:17, 1 June 2014 (UTC)


 * I work as a consulting engineer. My work involves doing calculations, based on data published in journals by scientists that have determined the data experimentally.  I concur with Semantic above - many times such experiments have not been repeated often enough.  If your reputation is determined by the success of your engineering, and that is dependent on the result of an experiment done by only one or two scientists, you have considerable risk - how do you know they haven't made a mistake or overlooked something, their description of experimental technique notwithstanding?  But if your calculation is based on an experimental value confirmed by dozens of scientists, using different methods and equipment, you can rest easy with great confidence.  I have found it surprisingly often that critical data has only been determined only once or twice.
 * Experimentally determined data that has important value (eg the velocity of light - used in all manner of calculations) tends to be confirmed by a great number of critically examined experiments, with with various techniques. Data that has had little or no commercial importance (until now) tends to have been experimentally determined by only one or two scientists.  As (by definition) a consulting engineer is involved in projects exploring new techniques and with considerable innovation, that's what we have to work with.  For example, I recently needed the thermal emmissivity of certain carbonates.  An extensive search turned up only two experimental values.  One, ~0.2, was an unpublished value used by a certain manufacturer.  One other value (0.30, stated to be independent of temperature) was published in a peer reviewed journal in 1962.  In principle it is a very simple thing to measure. But not a good situation when you need a reliable value within +,-0.01!  I resolved the problem by doing my own experiment, at some cost.  I found it varies between 0.18 to 0.31 over the temperature range 300 to 2000 K, with an uncertainty of +,-0.03.  So that 1962 boffin got it wrong.  Floda 121.221.223.1 (talk) 10:31, 2 June 2014 (UTC)

lactose intolerant
How do lactose intolerant people make it through childhood when all that babies eat is breast milk? Is there a difference in breast milk vs cows milk that explains how babies don't dehydrate from drinking milk? — Preceding unsigned comment added by 197philps (talk • contribs) 00:05, 1 June 2014 (UTC)
 * Have you read our article Lactose intolerance? Primary lactose intolerance (the common kind) develops only after infancy; congenital lactase deficiency (which affects even infants) is, on the other hand, a rare genetic disorder. Deor (talk) 00:19, 1 June 2014 (UTC)
 * (ec) Low-lactose and lactose-free versions of foods are often available to replace dairy-based foods for those with lactose intolerance, see Milk. When lactose avoidance is not possible then enzymatic Lactase supplements may be used. It was "normal" for humans to become lactose intolerant after weaning like most mammals; tolerance into adulthood of lactose found in milk is believed to have evolved by mutation in recent times, while lactose intolerance in babies is a genetic disorder. See Milk for comparison of human and cow milks; both contain water. 84.209.89.214 (talk) 00:33, 1 June 2014 (UTC)

negetive time
why can't we represent time in negative numbers or in second or third quadrant in graph? — Preceding unsigned comment added by 14.98.95.201 (talk) 05:36, 1 June 2014 (UTC)


 * This is a trick answer. Time is like any quantity; it is relative. You could choose time 0 to be any time and there would be negative time before that (we kinda do that with e.g. "200 BCE"). But the notion of "second or third quadrant" is not defined for time, which as far as we can tell, is a scalar quantity. The special theory of relativity clouds the picture a bit (and the general theory of relativity even more so), but that's the basics.--Jasper Deng (talk) 06:10, 1 June 2014 (UTC)


 * We might answer more meaningfully if we know what graph you have in mind, or in what context "we can't". —Tamfang (talk) 06:20, 1 June 2014 (UTC)


 * 130 years ago a character in a Gilbert and Sullivan opera sang about negative age:
 * Now, listen, pray to me,
 * For this paradox will be
 * Carried, nobody at all contradicente.
 * Her age, upon the date
 * Of his birth, was minus eight,
 * If she's seventeen, and he is five-and-twenty!
 * - Lord Mountararat in "Iolanthe" (1882)
 * Explanation: Mounterarat sings about the arcadian shepherd Strephon who is genetically 50% fairy. 84.209.89.214 (talk) 11:05, 1 June 2014 (UTC)

What does "g/d" mean in medial literature
I find the term g/d used in Wikipedia and medical literature, but I do not find the meaning of it by searching Google and Wikipedia. It is used on this page: https://en.wikipedia.org/wiki/Colostrum#Human_consumption_of_bovine_colostrum What does this mean, and would it be appropriate ask someone to add a Wikipedia page for it? Lloyd Ewing (talk) 06:18, 1 June 2014 (UTC)
 * Where do you see it? I don't see this abbreviation -- only mentions of IgG, IGF-1, PRPs and such.  Are you sure you linked to the right page? 24.5.122.13 (talk) 06:30, 1 June 2014 (UTC)
 * Missed it at first -- in this context, I believe it stands for grams/day. 24.5.122.13 (talk) 06:33, 1 June 2014 (UTC)
 * That's correct - see: http://www.exrx.net/Nutrition/Supplements/BovineColostrum.html and read "Summary and recommendations". The best thing with the article would be to add the explanation in brackets - which I have now done. Richerman    (talk) 10:16, 1 June 2014 (UTC)

Beans and Peas
What is the difference between beans and peas? Are they both fruits? — Preceding unsigned comment added by HubertVonRumpy (talk • contribs) 10:26, 1 June 2014 (UTC)
 * They're fruits in the broader sense, but more specifically they are Legumes, and are usually considered vegetables. ←Baseball Bugs What's up, Doc? carrots→ 11:08, 1 June 2014 (UTC)


 * This pdf from the University of Minnesota indicates a key difference is the shape - pea seeds are round and bean seeds are oval/kidney shaped. For most culinary purposes, beans come from the genus Phaseolus, whereas peas come from Pisum. Other sites indicate some behavioral differences between the two - peas use tendrils to climb while beans entwine their entire stems; peas like cool, wet weather while beans like hot dry weather; beans have solid stems while peas have more hollow stems. Of course, the divisions aren't necessarily clear cut - there are a number of peas and beans not in Phaseolus/Pisum, like fava beans and mung beans. There are also things like black-eyed peas, which are in appearance and culinarily used much like a bean (and were even under Phaseolus for a while). Then you have Cicer arietinum, which has a common name of both "chickpea", and "garbanzo bean". -- 162.238.240.55 (talk) 14:45, 1 June 2014 (UTC)


 * Love answering these permanently check-user-blocked accounts. Ask the farmers daughter.  She often sits among the beans and peas. μηδείς (talk) 17:16, 1 June 2014 (UTC)


 * The chickpea is also called the garbanzo bean, so apparently even the people who named it can't decide which it is. StuRat (talk) 18:00, 1 June 2014 (UTC)


 * Note that the OP is yet another blocked sock. ←Baseball Bugs What's up, Doc? carrots→ 18:36, 1 June 2014 (UTC)

conkers
Why do conkers have a light-colored patch on one side? See  — Preceding unsigned comment added by Commdlgdll (talk • contribs) 14:20, 1 June 2014 (UTC)
 * Looking at the example of acorns, it seems likely that that's the part of the seed attached to its outer shell. ←Baseball Bugs What's up, Doc? carrots→ 14:42, 1 June 2014 (UTC)
 * Note that the OP is yet another blocked sock. ←Baseball Bugs What's up, Doc? carrots→ 18:35, 1 June 2014 (UTC)
 * Blocked for disrupting the reference desk with bean/pea-related queries? 78.148.110.113 (talk) 17:19, 2 June 2014 (UTC)
 * More likely blocked for being a sock of a banned editor. ←Baseball Bugs What's up, Doc? carrots→ 19:47, 2 June 2014 (UTC)

Sunlight
What percentage of sunlight that strikes the Earths surface is absorbed by plants? How much is wasted? 190.203.241.182 (talk) 14:29, 1 June 2014 (UTC)
 * Define "wasted". ←Baseball Bugs What's up, Doc? carrots→ 14:42, 1 June 2014 (UTC)


 * The biggest question is what you want to include as "plants". If green algae are included - then most of the ocean is involved - if you're thinking only of land-based plants, then we have a VERY different answer.  This is going to be a tough question to answer directly because we would have to consider seasonal issues and so forth. Probably the best starting point is to look at Biomass.  Our article says that all living things except bacteria produce 100 billion tonnes of carbon per year.  Since animal biomass is derived either from eating plants - or eating other animals that eat plants - we can say that ultimately, that 100 billion tonnes was all initially locked up by plants, mostly powered by sunlight.  I suppose we could do the math to figure out how much sunlight it takes to do that.
 * However, our Photosynthetic_efficiency says that "the total photosynthetic efficiency of the planet is 0.84% to 1.26%" - which I think is the close to the answer you need...if you're including algae. It's saying that around 1% of sunlight being turned into biomass - but plants absorb about 28% of incoming sunlight and only use between 3 and 6% of that for making biomass...so maybe the true answer is more like 7 or 8% of incoming sunlight is "absorbed"...although even the word "absorbed" has a somewhat fuzzy meaning in this context.
 * SteveBaker (talk) 15:43, 1 June 2014 (UTC)

Higgs Boson
Did the large hadron collider actually find the higgs boson itself or just "possible evidence" that it "might exist" based on observed effects on something other than the actual higgs boson? Like saying water exists because you can hear the waves. Cremdelacrop (talk) 14:59, 1 June 2014 (UTC)
 * Why are you creating a new user ID for every question? ←Baseball Bugs What's up, Doc? carrots→ 15:00, 1 June 2014 (UTC)


 * How can you tell that anything exists?


 * You can't tell that (say) your breakfast "exists" other than by measuring observed effects on something rather than the actual breakfast. Photons of light reflected off the surface of the breakfast and captured by your eyes implies that there is a breakfast there - but it could be (maybe) a photograph of a breakfast - or a lump of plastic that's the exact size, color and shape as a real breakfast.  You can smell the breakfast - but again, that's only indirect evidence, perhaps there is a bottle of concentrated bacon essence behind the photograph.  Even if you touch or taste the breakfast - it's all indirect evidence through your senses.


 * At what point do you have to drop any doubt that this is really a breakfast and go ahead and eat it?
 * At what point do you have to drop any doubt that the "indirect evidence" collected by LHC is proof of the existence of the actual Higgs particle?


 * Tough question! The point is that you never, ever have "direct" evidence of anything whatever.  That's especially true for something like a Higgs particle - which is too small to detect with any of our senses directly.  We can't even generate a bucketful of Higgs bosons to play with at the macroscopic level.  We rely on instruments to do the measurements of those indirect properties.


 * So the answer is that we have evidence that's less firm than for (say) the photon and the electron - but more firm than for (say) super-strings and dark matter. Firm enough for the preponderance of scientists to proceed on the assumption that this particle exists?  Maybe.  I think the jury is still out on that one.


 * It helps that the Higgs wasn't just discovered by looking at data from the LHC - it was predicted to exist, predicted to have a particular set of properties and to be created at a particular range of energy levels.  The convincing part of this is that the theoretical likelyhood that it was there only had to be demonstrated experimentally.  Enough physicists were convinced enough by the theoretical existence of the Higgs to warrant spending a boatload of money to build the LHC to verify that fact.


 * So, year - the Higgs exists...at some high level of confidence...and while the evidence is "indirect" - so is all evidence of absolutely everything beyond "I think, therefore I am".


 * SteveBaker (talk) 15:57, 1 June 2014 (UTC)


 * Regarding the general theory of scientific knowledge: Well said, Steve!
 * We'd be remiss, though, if we let the discussion end at cogito, ergo sum. My good friend, who is a professional philosopher, frequently reminds me that scientists usually know philosophy up through the seventeenth or eighteenth century - in other words, we know cogito ergo sum because the philosophies of René Descartes preceded (or seeded) the scientific revolution.  But in the same sense that scientific knowledge has developed dramatically over the last few centuries, so has the theory of knowledge - the philosophy of how we know things to be true.  If you've got all Sunday free, and you've caffeinated your brain enough to handle it, you might be interested in Process Philosophy, developed by famous 20th-century mathematicians including Bertrand Russell and Alfred North Whitehead.  (Steve Baker frequently quotes a variation on the theme of Russell's teapot, or an invisible pink unicorn, so he might be interested in reading more about the reasoning behind that thought-experiment).
 * Essentially, we know things are true because we have agreed on a scientific method for defining truth.
 * Regarding the original questions, which is more specifically about the Higgs boson: CERN's front-page website confidently links to an informational page describing the Higgs boson - so this isn't some small foot-note at the bottom of some obscure publication. This isn't a mere puff-piece on a slow news day.  The world's preeminent research organization for particle physics is publicizing this information using a permanent link at the front and center of their webpage.  With confidence, the scientific community believes it has discovered a particle that is consistent with the Higgs boson predicted by the Standard Model.  This has been repeatedly observed by different teams using totally different experimental apparatuses, including the ATLAS and the Compact Muon Solenoid detector.
 * More research will certainly be conducted to quantify and qualify the physics. To understand the exact details of the particle that has been discovered, a reader will need to invest a lot of time to learn elementary and advanced topics in mathematical physics.  But if what you seek is a simple "yes or no" answer, then I think most informed physicists will say, "yes," we have already discovered the thing that everybody calls "the Higgs boson."  Nimur (talk) 17:06, 1 June 2014 (UTC)


 * Note that the OP is yet another blocked sock. ←Baseball Bugs What's up, Doc? carrots→ 18:33, 1 June 2014 (UTC)

plasmic electricity
in ITER and other fusion based energy( electricity) producing reactors ,water is heated and and used to make electricity. why can't we directly use the plasma produced as electricity. it is also a negatively charged particle state or type of electricity ? — Preceding unsigned comment added by 14.98.159.15 (talk) 17:12, 1 June 2014 (UTC)


 * The object is to eventually get a usable form of electricity delivered to homes, such as 60 Hz A/C at 120/240 V, here in the US. How would you get that directly from plasma ?   There's a similar problem with harnessing the electricity from lightning bolts.  StuRat (talk) 18:04, 1 June 2014 (UTC)


 * There ARE ways to produce electricity directly from plasma, but they're inefficient and a maintenance nightmare. 24.5.122.13 (talk) 23:49, 1 June 2014 (UTC)

weird-colored cottontail followup
Previous Discussion

Sorry I don't have any pictures, but for those who remembered or helped with the question about the oddly-colored cottontail my parents had as a resident in their yard in South Jersey a month ago, we have a follow up. Two weekends ago I almost stepped on a juvenile rabbit in their back yard, the same odd coloration as what I presume was his father's, normal grey undercoat and white tail, but with a browner saddle and dark lines around the ears similar to the suggested cinnamon rabbit (just not so broad). The only difference with this little one was a white star on the forehead like dogs and horses get.

Last night my parents and I were driving home to their house by an odd route to chek on a sick friend in the same neighborhood when an almost pure white rabbit with dark patches on the extremities ran past some kids on their lawn (they ignored it, so it was obviously known to them and not a run-away) and into the street where my father would have killed it except for my mother's screams. I said that was odd, and reminded them of our original dark rabbit and the recent bunny. My mother said she'd heard comments from three friends within about a sq km area that they had all seen oddly colored and patterned dark rabbits unlike any they'd ever seen before.

She found it odd a dark father might have a white offspring, but I reminded her that we had intentionally mated our blonde Shepherd with a whte sire and they had produced two blond, two silver, and two mostly black "rotweiler" patterned puppies.

Thanks for all the comments before.

Follow up question: do we have a good article on the coat color similarities found in animals like horses, dogs and guinea pigs with black and red-brown coats with white highlights? I have always been fascinated by the prevalence of that pattern across placental mammals. μηδείς (talk) 18:29, 1 June 2014 (UTC)


 * Uh-oh. If this is really a new species taking root, maybe we better get started on a rabbit proof fence... Wnt (talk) 20:06, 1 June 2014 (UTC)
 * That fence was a waste of money. Australian experience is that nothing stops rabbits.  Nothing.  During the 1930's Great Depression when the economy collapsed, rabbits proved to be an inexhaustible supply of easily caught food. Perhaps the USA should anticipate their entire country having this new rabbit in large numbers everywhere in the next few decades.  If you guys like rabbits, we can send you a few large wombats.  They are a sort of bar fridge size animal tank that wrecks all fences and man-made structures in its way, letting the rabbits through. Floda 121.221.223.1 (talk) 04:11, 2 June 2014 (UTC)


 * The pattern I think you may mean, μηδείς, is called the Agouti pattern. We seem not to have a full article on it but the one I linked, about the animal after which it's named, looks to have relevant links and reference, including to the (also sparse) Agouti gene article. {The poster formerly known as 87.81.230.195} 2.123.27.154 (talk) 21:13, 1 June 2014 (UTC)


 * To get at your question from a highly general and abstract position, I highly recommend Alan Turing's other ground-breaking work, The Chemical Basis of Morphogenesis, available here . In it he describes how a reaction-diffusion system can generate many of the coat patterns we see on animals, like zebra stripes, leopard spots, etc. It's fairly heavy on the differential equations but I think the paper can still be enlightening even if the math is skimmed. Pertinent to your question, things like rings on tails and darker ear tips can be explained as an interaction between the colorant agents and the geometry induced on boundary conditions. Some easier modern pop-sci follow-up and commentary here, . The general consensus is that Turing's work is mathematically sound, and an ok model for coat patterns, but that the actual details of how it works in real life are probably a bit more complex. So, the pattern you see as ubiquitous may be so because mammals have similar basic ways of developing patterns, and the dynamics are fairly conserved, even across widely different species. Once the basic ingredients are set up, it is the geometry of the mammalian body plan that causes certain features to appear as a lighter bib, eyebrows, etc. SemanticMantis (talk) 13:18, 2 June 2014 (UTC)