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

= August 24 =

World's biggest skyscraper
What's the world's biggest skyscraper by basically, uh, how big it is, that is the volume enclosed by the outside walls? I wonder how Shanghai Tower stacks up. 108.27.81.195 (talk) 00:45, 24 August 2013 (UTC)
 * See List of tallest buildings. Dismas |(talk) 00:54, 24 August 2013 (UTC)
 * I think 108 IP is asking about the biggest building by VOLUME, not height. But I have no idea where to get this info -- can someone help? 24.23.196.85 (talk) 01:06, 24 August 2013 (UTC)
 * See List of largest buildings in the world, which answers that very question. WHAAOE.  -- Jayron  32  01:07, 24 August 2013 (UTC)
 * Bah! I was close.  Was getting called away to something else while replying, so I didn't get a chance to double check.  Dismas |(talk) 01:11, 24 August 2013 (UTC)
 * The Boeing building is by far the largest building by volume, but it's not much of a skyscraper. The two lists linked here would need to intersect. ←Baseball Bugs What's up, Doc? carrots→ 02:52, 24 August 2013 (UTC)
 * I believe there's a Wikipedia tool for that (in fact, I used it not too long ago to look for movies set in London during certain time periods -- you just enter "Films set in London" and, say, "Films set during the 1940s", or in your case, "Largest buildings" and "Tallest buildings") -- does anyone remember what's this tool called? 24.23.196.85 (talk) 04:08, 24 August 2013 (UTC)
 * Are you perhaps thinking of WP:CATSCAN? Dismas |(talk) 04:10, 24 August 2013 (UTC)
 * Yep, that's the one! Thanks! 24.23.196.85 (talk) 04:14, 24 August 2013 (UTC)

Strongest known tornado outside of the United States; A question about the Fujita scale
I searched for this both online and in Wikipedia articles, but I could not find the answer. Basically, what is the strongest known or recorded tornado (in terms of intensity) outside of the United States? As a side question (although related), are either the Fujita scale or the Enhanced Fujita scale outside of the United States and Canada? Narutolovehinata5 tccsdnew 03:54, 24 August 2013 (UTC)
 * The article List of F5 and EF5 tornadoes has seven entries from Europe - see also List of European tornadoes and tornado outbreaks, List of Asian tornadoes and tornado outbreaks and List of Southern Hemisphere tornadoes and tornado outbreaks, although those articles generally don't have the intensities listed. The Enhanced Fujita scale is based on damage to typical American structures ("Manufactured Home – Double Wide", "Large, Isolated Retail Building [K-Mart, Wal-Mart]"), so I don't believe it's used outside the USA and Canada - our article doesn't say otherwise. Tevildo (talk) 11:53, 24 August 2013 (UTC)
 * According to this website, there were two strongest tornadoes in Europe, both T10-T11 on TORRO scale (one struck France on 19 August 1845 and the other one Italy on 24 July 1930). In terms of deaths the strongest one seems to be Daulatpur–Saturia tornado. Brandmeistertalk  13:57, 24 August 2013 (UTC)

Astigmatisms and autostereograms
I'm looking for solid references (preferably ones that pass WP:MEDRS) discussing astigmatisms and autostereograms, but so far all I've found are forums and similarly unreliable sites at which people chat about the subject. Basically looking for something explaining the effects (or lack thereof) of astigmatisms on astigmatics' ability to "do" autostereograms, but something talking about other aspects of the process of "doing" autostereograms for astigmatics would be helpful. A little context, in case that help — I've been trying fruitlessly to teach an astigmatic acquaintance how to "do" autostereograms, and I'd like to know if the literature suggests that it's impossible/harder/no different/whatever. Nyttend (talk) 12:38, 24 August 2013 (UTC)


 * Firstly - there are two very different uses of the term "astigmatism" - one form (which I have in one eye) is when the lens of one or both eyes is not spherical so the focal distance is different vertically and horizontally and things are perpetually blurry in one direction or the other. This is easily corrected with glasses or contact lenses - and even uncorrected, it does not prevent one from seeing autostereograms (I see them just fine).


 * The other use of the term is for people who's eyes don't move correctly to line up on the object being concentrated on. They may be cross-eyed or have a lazy eye.  Those people cannot see autostereograms because they rely on correct positioning of the two eyes to produce a 3D image.


 * So we're only talking about the SECOND kind of astigmatism. But it's even more confusing than that.


 * The problem is that MANY people are born with slightly crossed eyes or a "lazy eye" (Astigmatism-of-the-second-kind). In almost every case, this fixes itself within a month or so of birth - and all is well.  But for about 5% of people, it takes three or more months to "fix itself" and once the obvious problem goes away, it seems like the person can see just fine


 * However, what happens (without medical intervention) is that the circuitry in the brain that learns how to fuse two separate images into a single three-dimensional representation doesn't develop properly in those people because this part of the brain forms in the first few months after birth. This problem has only been properly recognized in the last 20 years or so - and it's only properly diagnosed and treated (eg with eye patches) in a few places in the world.   This afflicts about 5% of the population (although that number is dropping as the problem is recognized).


 * If you're one of the 5% then both of your eyes work fine, you can have 20/20 vision and your eyes can track targets perfectly - but your depth perception is not as good as it should be - and things like 3D movies and virtual reality headsets don't seem any better than 2D movies and 2D computer graphics. These people are easily recognized because they say things like "I don't see what the big deal is with 3D movies - they don't look any different!"  But the problem with autostereograms is worse because the "image" is only present as a 3D displacement - so for people in the 5%, they stand NO CHANCE of understanding them.


 * There have been some successes in treating this condition - it seems that brain plasticity is sufficient that the problem can be treated with special exercises (at least in some cases). People who have had the treatment are AMAZED at how much different the world looks afterwards.


 * SteveBaker (talk) 15:48, 24 August 2013 (UTC)
 * The "second kind" you describe is strabismus; I haven't heard it called astigmatism. While it is clear that strabismus would interfere with stereograms, I think it is conceivable that astigmatism would also prove something of a hindrance, because any distortions imposed by the lens would appear to go in different directions for the two images to be fused, making them more difficult to align. Wnt (talk) 16:37, 24 August 2013 (UTC)
 * Not trying to sound unappreciative, Steve, but I'm specifically looking for solid sources, e.g. something in an ophthalmology or optometry journal discussing the subject. Nyttend (talk) 17:03, 24 August 2013 (UTC)
 * Yeah - I understood that (I don't have such things) - but I did want to clarify that a mindless search for "astigmatism" would produce confusing results. Also, even people who's eyes do all the right things may fail at understanding autostereogram because of the brain development thing.  It would be necessary to be sure that an astigmatic (type I) was failing to understand an autostereogram because of the astigmatism rather than because of happening to be one of the 5%. SteveBaker (talk) 22:58, 24 August 2013 (UTC)

What scientific problems have been proven impossible to determine?
--121.7.36.13 (talk) 13:12, 24 August 2013 (UTC)


 * None (by definition). Dauto (talk) 13:52, 24 August 2013 (UTC)
 * Science does not deal in absolutes like proofs. We can prove scientific facts only ever with respect to a given theory, and support for a scientific theory is always tentative in principle (although what a scientist considers "tentative" is often more certain than what we consider "facts" in everyday life). There are a number of problems in math (including theoretical computer science, mathematical logic, and similar disciplines) that are proven to be impossible to answer in general. Examples include the Halting problem, the Post correspondence problem, and the Entscheidungsproblem. --Stephan Schulz (talk) 13:56, 24 August 2013 (UTC)
 * Even proving you can't for instance solve the halting problem doesn't mean there can't be an oracle machine that always gives the correct answer. It is very highly improbable though! Dmcq (talk) 14:33, 24 August 2013 (UTC)
 * There are many concepts which seem, at first glance, to be simple to the uninitiated which are, not merely difficult to prove, but actually proven to be impossible to determine. Many of the concepts surrounding "quantum" fields are governed by the Uncertainty principle, for example, which doesn't merely state that somethings are outside our current technological grasp of determining, but that they are physically impossible to determine, for example certain pairs of properties, such as momentum and position, are impossible to know simultaneously for any sufficiently small particle.  -- Jayron  32  14:54, 24 August 2013 (UTC)


 * No - the proof relating to the halting problem doesn't say that you can't solve it - only that a Turing Engine can't solve it. I could disagree though that the halting problem "has proven impossible to determine" though - we've looked at it - and we are 100% sure that you cannot write a computer program that looks at another computer program and tells you whether that program will halt or not.  This isn't some kind of mysterious unsolved problem - it's that we have total and complete certainty that some particular determination cannot be made.  It's like the laws of thermodynamics say that you can't make a perpetual motion machine - or that the uncertainty principle says that you can't simultaneously know the position and momentum of an electron - or that godels' theorem shows that there exist some class of mathematical theorems that can never be proved or disproved.
 * I think we should help the OP to refine the question a bit. There are many areas of doubt to consider:
 * Some things we know for 100% certainty cannot ever exist: A Perpetual motion machine or a computer program that can tell whether other computer programs will eventually halt or not, an engine that'll propel a spacecraft at the speed of light...that kind of thing. It's not just that we haven't discovered a way to make these things - it's that we know for 100% sure that they are impossible.
 * Some things we know for 100% certainty we cannot ever measure: The nature of light from a star that lies outside of the observable universe, the exact position and momentum of an electron. These are fundamentally unknowable things.
 * Some things we definitely don't know - but might one day know: What is dark matter? What caused the first living thing to appear on earth?  More research is needed - but we can probably work out the answer somehow.
 * Some things are reasonably well known but not with sufficient accuracy: Are there planets orbiting other stars that are habitable by humans? (Almost certainly - but maybe not.)  How much temperature rise will we experience if we continue to dump CO2 into the atmosphere at present rates?  (Definitely too much...but we don't know exactly how much too much.)
 * Some things that we expect to be true but cannot yet prove: Can every even integer greater than 2 be expressed as the sum of two primes? (We're pretty sure that the answer is "Yes" - but we can't yet prove it.)
 * Some things that we thought were probably true for the longest time - but were finally disproved: Euler's sum of powers conjecture, for example.
 * Some things that nearly everyone thought were false for the longest time - but were finally proven true: Continental drift, for example.
 * Some things that we thought were true - but are only approximately true - or are only true in special cases: Newton's laws of motion, for example.
 * Some things are "unfalsifiable" - we can never prove them false, but they might one day turn out to be proven true: The existence of God, The "simulation hypothesis", for example.
 * Some pairs of ideas that both seem to be "proven" true - but are contradictory in nature so either we're missing something, or one or both of them must actually be slightly incorrect: Gravity and Quantum Theory, for example. Gravitational theory works great at large scales and Quantum theory works great at small scales - but when the two intersect (eg at the boundary of a black hole), they predict different outcomes - so we know there is a problem somewhere.
 * Some things that many non-scientists THINK scientists have trouble with - but which are actually well understood: How come a bee can fly with wings that seem to be too small? (Wingtip vortices are exploited by bees in a way that was not obvious to one writer - and everyone took that as "Scientists say that bees can't fly - look how stupid scientists are!")
 * I'm sure there are other categories of doubt and error that I haven't thought of...but to find concrete examples, our OP needs to be much more specific. SteveBaker (talk) 15:28, 24 August 2013 (UTC)
 * Good list, but you are confusing the two most distinct classes. The Halting problem is proven to be impossible to solve for a Turing machine (or, indeed, any kind of algorithmic machine - the diagonal proof does not really depend much on the specifics of the machine). A perpetuum mobile, on the other hand, is impossible under the laws of thermodynamics. But the laws of thermodynamic are just very well-supported assumptions. There is nothing logically impossible about them changing tomorrow (just assume that reality is a giant computer simulation, and tomorrow they put in a new patch). But there is no patch to reality that makes a the Halting problem for general Turing machines solvable. Of course, the Halting problem for real computes is trivially solvable (in theory), since they only have a finite number of states. --Stephan Schulz (talk) 16:26, 24 August 2013 (UTC)
 * Thermodynamics is a bit of a tricky case - see Constantin Carathéodory, who formulated a derivation of the second law based entirely on mathematics (and the concept of "heat", which may reconnect it to the physical world - I'm not a good enough mathematician to comment). It's on a lot firmer ground than special relativity, at least. Tevildo (talk) 16:39, 24 August 2013 (UTC)
 * (ec) A good answer, as always, but I'm not sure about all of the "100%" examples. I would say that we should distinguish between mathematical propositions (such as the halting problem), which can be conclusively proved, and scientific propositions (such as the inability for a spacecraft to reach c).  The contradiction of such a statement will be inconsistent with our current understanding of the universe, but it's not _impossible_, in the way that a solution to the halting problem or a proof that 2 + 2 = 5 would be.  (Incidentally, the non-observability of light from a star outside the observable universe is an analytic truth that doesn't even require mathematics to demonstrate - the fact that the observable universe is finite is a tentative scientific proposition that could (theoretically) be false). Tevildo (talk) 16:35, 24 August 2013 (UTC)

See also here:

"Stewart, on the other hand, considers the RAC, whose clock accelerates exponentially fast, with pulses separated by intervals of 1/2, 1/4, 1/8, ... seconds. So the RAC can cram an infinite number of computational steps into a single second. Such a machine would be a sight to behold as it would be totally indifferent to the algorithmic complexity of any problem presented to it. On the RAC, everything runs in bounded time. The RAC can calculate the incalculable. For instance, it could easily solve the Halting Problem by running a computation in accelerated time and throwing a switch if and only if the program stops. Since the entire procedure could be carried out in no more than one second, we then only have to examine the switch to see if it’s been thrown. The RAC could also prove or disprove famous mathematical puzzles like Goldbach’s Conjecture (every even number greater than 2 is the sum of two primes). What’s even more impressive, the machine could prove all possible theorems by running through every logically valid chain of deduction from the axioms of set theory. And if one believes in classical Newtonian mechanics, there’s not even a theoretical obstacle in the path of actually building the RAC. In Newton’s world, we could model the RAC by a classical dynamical system involving a collection of interacting particles. One way to do this, suggested by Z. Xia and J. Gerver, is to have the inner workings of the machine carried out by ball bearings that speed up exponentially. Because classical mechanics posits no upper limit on the velocities of such particles, it’s possible to accelerate time in the equations of motion by simply reparameterizing it so that infinite subjective time passes within a finite amount of objective time. What we end up with is a system of classical dynamical equations that mimics the operations of the RAC. Thus, such a system can compute the uncomputable and decide the undecidable." Count Iblis (talk) 18:16, 24 August 2013 (UTC)
 * That's actually a good example of mathematics driving science. Such a machine could solve the halting problem.  But solving the halting problem is _mathematically_ impossible.  So such a machine's existence is _theoretically_ impossible, not just _practically_ impossible. Tevildo (talk) 18:38, 24 August 2013 (UTC)
 * Thinking about it, this might rescue special relativity. If we could accelerate material objects to infinite velocities, we could solve the halting problem.  But we can't solve the halting problem.  Ergo, we can't accelerate material objects to infinite velocities.  Ergo, Newtonian mechanics has to be modified so that infinite velocities aren't possible - we have to introduce a velocity limit.  Is there a convenient formulation which reduces to Newtonian mechanics when velocities are much less than the limit?  Yes, the Lorentz transformation!  I'll expect my Nobel prize notification in the post.  (Oh, some German chap apparently did this already.  Bummer.) Tevildo (talk) 18:44, 24 August 2013 (UTC)


 * Mathematics says that no turing machine can solve the halting problem for turing machines. The argument is, essentially, the same used to show the reals are uncountable (assume the negation of the theorem, diagonalize, show the outcome isn't in the set). At any rate, the machine described wouldn't violate the theorem since it wouldn't be a turing machine. On a deeper level, though, even if you built a computer that was, by all means, normal and, then, got it to compute the halting machine; all you would have shown is that electronic computers aren't actually modeled by tm's- nothing mathematical. At best, you can disprove that the mathematics you are using applies to the phenomena at hand, the mathematics themselves are not tested by the phenomena. (this is exactly what why the math used in classical mechanics is still perfectly legit as mathematics).Phoenixia1177 (talk) 05:55, 25 August 2013 (UTC)
 * True, of course, although one could still violate the theorem by shelling out from a Turing machine's code to the RAC machine. It could also do various other, more self-evidently impossible, things, such as calculate all the digits of pi or (which is basically the same thing) square the circle to an arbitary (including down to zero) precision.  Shall we say that it couldn't exist in any possible world, which gives us an (admittedly fairly broad) limitation on the fundamental equations of physics in any possible world? Tevildo (talk) 16:45, 25 August 2013 (UTC)
 * I might have to take that back, because it _couldn't_ produce a list of all the real numbers between 3.1 and 3.2. I still think the basic point is valid, though. Tevildo (talk) 16:53, 25 August 2013 (UTC)
 * That wouldn't be violating the theorem anymore than pointing out that there is an ordinal number larger than any natural number violates "there is no largest number"; it'd just be a confusion of two notions of number. The same thing is happening here: what you are talking about would be a "computation" in a certain sense, but it wouldn't be a computation in the sense of "computed via TM". Indeed, the theorem itself tells us exactly that, if there is no turing machine that solves the halting problem and you can solve the halting problem, then you aren't doing something that can be done with a turing machine; in the same sense that I know infinite ordinals aren't natural numbers (ignore nonstandard models) since they are larger than every natural. The most you could claim is that the Church-Turing Thesis is wrong. (as an aside: turing machines, basically, are just a means of specifying a set of naturals (or function of them), there are obviously sets/functions they don't define, that one of these might be "computed" by some natural phenomena only tells us that nature isn't limited by TM's- much in the same way that it isn't limited to the computational processes of Pushdown automata and subsets corresponding to context free languages.) (A final point: unless you are exceptionally generous to the point of rendering the notion of "computation" meaningless, you are always going to end up with systems that can't decide their own halting problem unless they are quite weak, or overly big- to stick with the arithmetic analogy, it's like trying to avoid various prongs of Godel's Theorems by working in Presburger Arithmetic or True Arithmetic, you just end up impaled elsewhere- in other words, if you find a way to avoid halting problems, you're equivocating models of computation or throwing out the baby, bathwater, and the whole damn bathroom.) By the way, I don't know if we have an article on it here, or the proper name for it, but some folks have studied computation over other ordinals, that may have some relevance to what you are talking about; if the theoretical background is something you find of interest. I have a book on it somewhere, if I can find it and you want, I can give you the title/authors.Phoenixia1177 (talk) 19:01, 25 August 2013 (UTC)
 * I would say that if the solution to a problem cannot possibly be determined, then it is not a scientific problem. TFD (talk) 18:54, 24 August 2013 (UTC)


 * Hence my answer at the very beginning of the thread. Dauto (talk) 21:26, 24 August 2013 (UTC)


 * You both TFD and Dauto are confusing science as the process and science as the result. The other respondents are on the money. See also Undecidable problem for the basis of Stephan Schultz explanation. OsmanRF34 (talk) 22:36, 24 August 2013 (UTC)


 * Those are mathematical not scientific problems, unless you want to consider mathematics a science. TFD (talk) 17:00, 25 August 2013 (UTC)


 * No, no confusion. I'm just applying my favorite definition of science to the question. Dauto (talk) 18:28, 25 August 2013 (UTC)


 * Science doesn't solve any mathematics problems, undecidable or decidable. I would also agree that there aren't any unsolvable science problems since the universe solves them all quite fine. At best, you can get what looks like an unsolvable problem by misusing language; for example, you could say that it is unsolvable to determine what the momentum and position of a particle is at the same time, but you are really just abusing classical and quantum notions of position, momentum and property (the solution to a lot of seemingly intractable problems has been finding the flaw in our language and definitions, not any barrier in nature.)Phoenixia1177 (talk) 19:20, 25 August 2013 (UTC)
 * I'm not sure I buy that answer. The universe produces the exact solution to the Three-body problem - but we can't.  It can figure out what the weather will be three months from now - but we can't.  I think it's a bit simplistic to say that the universe "solves" things.  "Solving" some system means being able to understand and make a useful prediction about it.  The Universe does neither. SteveBaker (talk) 22:34, 25 August 2013 (UTC)
 * In a practical sense, I agree completely; however, we're talking about things that are "impossible" to solve. We, as in humans today, can't solve the three body problem; however, that doesn't mean it is impossible for it to be solved. My point, essentially, is that for something to be impossible to solve requires that there is no model that can give the result; but, nature itself provides the results. For example, if it is impossible to predict the weather because it requires computing something that can't be done on a turing machine, then it turns out that turing machines aren't the ultimate limit on what should be called computation, because I have something that does just such computations, the weather. But, even more fundamentally, if something were "impossible" to solve because no model gave a unique right answer*, just various answers that work, then the real question is if the terms actually make sense. *For example, if there is some property that is odd or even and a process such that the end result is always even, then asking for the parity of the input of a given output may seem impossible; however, if no observation can distinguish the cases "was even" and "was odd", it's hard to call the problem scientific since science is observational.Phoenixia1177 (talk) 14:17, 26 August 2013 (UTC)


 * The three body problem cannot be solved analytically, but it can be solved numerically to any desired level of precision. That counts as a solution in my book. Dauto (talk) 15:02, 26 August 2013 (UTC)

Why do the women have less blood than men?
←I've seen once (I don't remember where) a math formula of calculation for a blood quantity in the person. So, according to the formula, when you ask how much blood this person has, if he is a man you give 0.75 mililiter for every one kg of his body, and if she is a woman you give 0.65 for every kg of his body, and if it's baby you give 0.85 for every kg of his body. So, first of all, I would like to know if is it true. and second, according to this formula we can understand that the woman has less blood than man. In example, when a man is 60 kg, he has 4.5 liter of blood (60 times 075), when a woman is 60 kg she has 3.9 liter of blood, it's happen when both of them is in the same weight! It's about 13.5 percent less compared to a man. So, to sum up I have two questions, but the one depends in the another one: 1. is the formula true? (and if it's true, what is his origin). 2. why the women have less blood thatn men. 95.35.88.167 (talk) 18:18, 24 August 2013 (UTC)


 * Your units are wrong - those should be deciliters (dL) per kg, or you need to shift your decimal over a couple of places - but the values are approximately correct. The difference between men and women is primarily down to different body fat percentage.  Adipose tissue (fat) contains less blood per kilogram of total weight than muscle or most organ tissues.  The average amount of circulating blood per kilogram of body weight is lower in obese individuals (fat makes up more of their total body weight) and higher among young people.  Infants can go higher than 100 mL of blood per kilogram: .  All these numbers are approximate, and will vary from person to person and study to study. This paper shows the distributions of values for typical children and adults at various stages of development.  Note that figure 1B plots blood volume per kg of body weight, whereas figure 1A plots volume per kg of lean body mass&mdash;the values become statistically indistinguishable in adult males and females when you eliminate the contribution of body fat.  TenOfAllTrades(talk) 20:39, 24 August 2013 (UTC)
 * No male is allowed to talk about it, but I have heard from a wise (dirty) ole man that it is something to do with the "monthlies"...Myles325a (talk) 07:02, 29 August 2013 (UTC)

metal mixture
I want to mixture of 50%copper+ 15%silver+12%cadmium+23%zinc but its breaking when I want make its its 37guage stripe. Why? You have any solution or metal which helpful to make its soft?? — Preceding unsigned comment added by 59.161.69.236 (talk) 19:57, 24 August 2013 (UTC)


 * A few points
 * The properties of a metal alloy may be very sensitive to the particular process used to make them.
 * even small amounts of impurities may have large effects.
 * how are you attempting to make the stripe? Hot or cold? Cutting or stretching? details do matter.
 * Dauto (talk) 21:21, 24 August 2013 (UTC)


 * Are you using Sheet metal measurement here - 37 gauge = 0.17 mm ??


 * Why waste good silver mixing it with cadmium and zinc? Cadmium in particular has sort of a mixed reputation.  I suppose it's better than lead, but...  well, anyway, our article on solder does mention "Sn-3.5Ag-0.74Cu-0.21Zn" (reading down I see there are several of these, but all 95% tin)  Also "KappRad" Sn40Zn27Cd33.  It looks like the solder recipes are meant to be near eutectic points for low melting temperature, which may not matter.


 * Point is: where did you get this recipe? If you're reinventing metallurgy on your own you'll have many disappointments.  (I do wonder if you might find tin, due to its ductility, a component preferable to cadmium?  Or maybe bismuth?  But I am so not qualified to say any such thing!) Wnt (talk) 23:13, 24 August 2013 (UTC)


 * There are some alloys fairly close to the OP's mixture at List of brazing alloys, but everything we list has a larger Ag/Cu ratio. Tevildo (talk) 23:35, 24 August 2013 (UTC)


 * Yea, copper is quite ductile, and silver is fairly ductile, too. I'd suspect the problem is the cadmium and/or zinc, making it too brittle.  Try lowering the ratio of one or both of those. If you need to keep that ratio, you will have to treat it more gently, like only work it a small amount, then reheat it and let it cool, to relieve the stress, before working it again. StuRat (talk) 01:36, 25 August 2013 (UTC)

A mineral that heats on contact
Is this really a special mineral with such characteristics, or just a normal hot rock? If it's the former, what's it called? Thanks, 84.109.248.221 (talk) 23:06, 24 August 2013 (UTC)


 * Looks like a typical internet fake to me. If the rock had been buried in the ground and emitted heat sufficient to char paper for thousands, perhaps millions of years until it was dug up - what would be the power source for such a thing?  To my eyes, it looks like a lump of coke or even a barbeque briquette that someone heated up and then used to take the photos.  We only have his word that it was hot when dug out of the ground.  Yeah - maybe it could just maybe be radioactivity - but the amount of radiation it would take to make that much heat would probably have killed the guy who took the photos by now. SteveBaker (talk) 03:34, 25 August 2013 (UTC)


 * It's definitely not radioactive, it'd be quite lethal if so; most likely, it's a hoax. However, on the chance that it isn't: the outcomes look more like a chemical reaction (the glove doesn't look burned, but stained.) It could be a bunch of Iodine prills, or crystals, stuck together some way. While such a find would be exceedingly unlikely for any legit (or natural) reason- iodine can be used to manufacture meth, someone may have stumbled on a stash of it. At any rate, like I said, that's all quite unlikely, it's probably a scam.Phoenixia1177 (talk) 05:45, 25 August 2013 (UTC)
 * I also thought it looked like it could be iodine, both due to the black discoloration of paper and the brown discoloration of the glove. The "metallic" appearance isn't really that far off from iodine either.  However, I assume the "rock" results from some industrial source, not meth manufacture.  (the second is more newsworthy, but not really that big a chunk of the overall use of the element!) Wnt (talk) 08:05, 26 August 2013 (UTC)

It is quite clearly iodine crystals. I've seen this several times on the Internet recently, with different stories.