Wikipedia:Reference desk/Archives/Science/2010 July 15

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July 15

Magnetic Field

After reading this, what symptoms would a human feel if they were levatating in a magnetic field? Reticuli88 (talk) 02:04, 15 July 2010 (UTC)

Your brain would explode. Well, not really, but a field strong enough to do that would cause massive epileptic seizures, probably paralyze the lungs, and very likely cause the heart to go into fibrillation. Looie496 (talk) 02:57, 15 July 2010 (UTC)

Says who? Neither the frog nor the cricket "exploded" when levitated [1]. They both remained active while levitating, and while there is no way to know the internal quality of their experience, neither seemed harmed after wards. Keep in mind that it is a static field (albeit a spatially varying one), so there isn't a large electrical component which seems to be what you are basing your response on. Also, the field strength in the levitation example is only about 12 times larger than is routinely used in magnetic resonance imaging with no substantial ill effects. There probably would be some strange sensations, but it is not obvious to me that it would be fatal or even dangerous to humans. (Though anyone wanting to try it should certainly run many safety tests first.) Dragons flight (talk) 03:56, 15 July 2010 (UTC)

I do not think one would "explode" or have any substantial ill effects, maybe if you were to move in the magnetic field. Magnetic levitation of water on earth (approx. humans) needs a gradient in the magnetic field of 1400 T^2/m, since a lying human is at least 25 cm high levitation of a human needs at least 19 T while levitation of a frog that moves in any direction and is 2 cm needs at least 5 T. even stronger field are probably needed in order to get stability and uniform levitation in all parts of the body. A lying human will probably need 50 T and a standing human will need 150 T. This is far stronger than the strogest magnets on earth. —Preceding unsigned comment added by Gr8xoz (talk • contribs) 05:22, 15 July 2010 (UTC)

But why would it do this? Reticuli88 (talk) 03:06, 15 July 2010 (UTC)

It would feel like free fall (like in the space station), free fall is commonly (but incorrectly) referred to as no gravity. Note: Free fall (and no gravity) does not feel like floating, it feels like falling. It takes a while to get used to that. It does not feel like floating in water. Ariel. (talk) 06:19, 15 July 2010 (UTC)

I'm skeptical that it would feel like free fall -- specifically, you're not falling. You're stationary in a grav field, just as you are when you're standing on the ground, only you're not standing on the ground. Gravitational effects should be unchanged. A skydiving simulator (with the giant fans in the floor) would be the easier-to-access analogue; has anybody played with one? — Lomn 11:50, 15 July 2010 (UTC)

I agree with Ariel. As far as the magnetic force per kg is uniformly equal and opposite to gravity, it is like free fall, unlike a force of wind acting on the surface.--Patrick (talk) 13:26, 15 July 2010 (UTC)

In traditional free fall, what force is acting equal and opposite to gravity? — Lomn 14:17, 15 July 2010 (UTC)

It would feel like free fall, because the forces that act on your body do so without causing much deformation; they act approximately uniformly per unit mass. The reason why standing on the ground does not feel like being in free fall is because the normal force only acts on the boundary of the ground and your body. This force only causes the atoms that touch the ground not to accelerate through the floor. But the next layer of atoms in your feet also don't accelerate, and this is due to the fact that they move a bit closer to the atoms on the boundary and then experience a force exerted by the atoms on the boundary. So, the normal force is transferred to the whole body via deformations. You can feel the internal stresses that this causes. Count Iblis (talk) 14:36, 15 July 2010 (UTC)

It should be noted that free fall (as used in this context) is not the same situation as one might experience in (for example) those skydiving simulators with the giant fans. (It's rather an awkward problem of terminology — physicists tend to talk about free fall as meaning a situation where a body is not significantly affected by drag, whereas skydivers use it to mean all the time before they deploy their parachutes.) In a skydiving simulator, one is experiencing the equivalent of a fall through air at terminal velocity, where the gravitational force on your body (indeed, on all of the infinitesimal parts of your body) is evenly matched by the drag force applied to your lower surface by the upward blowing air. As Count Iblis describes above, in the skydiving simulation the forces are actually quite similar to what you would experience lying on the ground. Force is applied to whatever part of you is 'down', and then conveyed through the body. It's not 'free fall' in the physicist's sense, because each part of your body can tell that force is being applied from its underside to lift it, and in turn applies upward force to support the parts above. When at terminal velocity while skydiving, your body can readily sense which direction is 'down', by much the same mechanisms by which you know which way is 'down' when you're lying in bed.

In contrast, the diamagnetic levitation effect acts on the entire body, fairly evenly. (At least, this is my understanding.) Instead of applying a countergravitational force to the bottom surface of the levitated body, it provides a small, uniform lift to every bit of mass throughout. Bits of matter on the 'bottom' don't have to support the weight of bits of matter on the 'top' — and that makes a huge difference to the sensations of the individual being so levitated. It's really a free fall as far as the body is concerned. (Actually, I've cheated a bit in my definitions here, too. Usually 'free fall' for physicists means that a body is only being acted on by gravitational force. In a sense, what we're doing here is applying a bit of 'antigravity' through electromagnetic means to null out the effects of gravity. What an object experiences here is probably functionally close to real zero gravity — locally flat spacetime, with no gravitational force acting.) TenOfAllTrades(talk) 15:06, 15 July 2010 (UTC)

And now I'm going to respond to myself, and note that the perception of weightlessness or freefall is going to be even more complicated than we'd like in this situation, because the diamagnetic levitation effect is going to affect different materials slightly differently. The magnetic permeability of bone is going to differ from that of soft tissue, for instance, which means that the amount of levitation force felt by each type of tissue will also be slightly different. What effect this will have on the perceptions experienced by the vestibular system I couldn't guess. TenOfAllTrades(talk) 20:14, 15 July 2010 (UTC)

About strong static fields:

The strongest magnetic field that you are ever likely to encounter personally is about 10^4 Gauss if you have Magnetic Resonance Imaging (MRI) scan for medical diagnosis. Such fields pose no threat to your health, hardly affecting the atoms in your body. Fields in excess of 10^9 Gauss, however, would be instantly lethal. Such fields strongly distort atoms, compressing atomic electron clouds into cigar shapes, with the long axis aligned with the field, thus rendering the chemistry of life impossible. A magnetar within 1000 kilometers would thus kill you via pure static magnetism -- if it didn't already get you with X-rays, gamma rays, high energy particles, extreme gravity, bursts and flares...

Count Iblis (talk) 14:44, 15 July 2010 (UTC)

MRIS give me headaches though. I don't know whether it was the placebo effect but I actually believed there were induced currents and depolarisations running through my brain. John Riemann Soong (talk) 15:03, 15 July 2010 (UTC)

I don't think it's a placebo effect, it's well documented that many individuals feel "weird" a bit while around the large MRI devices. I personally feel a bit nauseated and dizzy when I have to stick my head in the bore. -- Sjschen (talk) 21:19, 15 July 2010 (UTC)

On safety, it's worth noting that clinical MRI instruments now regularly reach fields of up to about 7 tesla ([2]), and there are some small-bore instruments (for wrists and knees and such, rather than the whole body) which have fields up to 9.4 tesla or more. There has been some fairly extensive testing on the effects of these high fields on the human body. You can start here or here and work back through their references. Meanwhile, the levitating frog demo was done at a field of 16 tesla. In other words, we're actually not that far from exposing humans to sufficiently high field strengths for this sort of levitation — though generating a full-human-sized 16 T field represents a non-trivial engineering challenge. TenOfAllTrades(talk) 15:17, 15 July 2010 (UTC)

A doctor once told me that an MRI produces "1,000 times the radiation of a chest X-ray". So I didn't get one. ~AH1^(TCU) 18:50, 16 July 2010 (UTC)

Sounds like you need to get a doctor who can tell the difference between an MRI and a CT scan. --Carnildo (talk) 00:45, 17 July 2010 (UTC)

safe use of electric fields on cells

I'll be looking at the literature, but can anyone suggest to me a safe threshold for electric fields to induce excitement in cells (especially constitutive exocytosis). Preferably protocols that minimises any membrane depolarisation, and definitely minimises the risk of apoptosis and mass cell death. I want to stimulate the cells, not stress them.

I'm trying to track nanoparticles for several hours within *live* cells being observed under a (very expensive) microscope for several hours. What voltages and currents should I use? We do have batteries and various apparatuses (but we normally use them in vitro rather than to induce anything in vivo). I am working with lung cancer epithelial cells, not nervous or neuroendocrine cells. John Riemann Soong (talk) 03:36, 15 July 2010 (UTC)

Membrane depolarization is the signal that transmutes an electric field into a cellular response, so asking for excitement without depolarization is a contradiction. In any case, generally tissue destructive effects are determined more directly by current than by voltage, and more by how long a current is sustained than by how strong the current is. Figuring out how strong a field you are creating with a given stimulus protocol is likely to be very difficult. If you want to apply electric fields, I advise getting hold of a device called a "stimulus isolator", if you don't already have one. They are standard equipment in electrophysiology labs. Looie496 (talk) 23:47, 15 July 2010 (UTC)

Well actually I'm trying to activate voltage-gated channels without causing any runaway effects. I guess that's what I meant. John Riemann Soong (talk) 15:54, 16 July 2010 (UTC)

Glowing yellow glass

Recently I discovered a yellow glass marble in the street and brought it home, and noticed that it glows a bright yellow-orange under blacklight. I also noticed that a red glass paperweight was glowing yellow as well, but only around the edges (where it appears yellow in ordinary light). What causes these glass items to glow this way? 68.123.238.146 (talk) 03:58, 15 July 2010 (UTC)

The yellow marble is Uranium glass, also called Vaseline glass, which fluoresces bright green-yellow under UV. Acroterion _(talk) 04:15, 15 July 2010 (UTC)

And just in case you're worried - these objects are not especially radioactive. We're not talking about the isotopes of uranium that produce the most radiation - and anything they do produce will mostly be absorbed by the surrounding glass. What is interesting is that uranium glass hasn't been made in any quantity for 60 or more years - so these objects could be rather old. SteveBaker (talk) 12:33, 15 July 2010 (UTC)

Could be. But as the article notes, marbles are one of the few modern uses of uranium glass. Matt Deres (talk) 13:22, 15 July 2010 (UTC)

Just don't crush and insufflate them, in case you were considering that. --Sean 17:11, 15 July 2010 (UTC)

Backing up a moment, I re-read the OP: he said that it fluoresces "yellow-orange", which isn't a characteristic of uranium glass (it was late, I mis-read). Perhaps I was wrong about this particular marble. Apparently manganese can produce an orange fluorescence [3].Acroterion _(talk) 15:34, 15 July 2010 (UTC)

Heisenberg quote on quantum mechanics and Indian philosophy

I have seen in many places the quote "After the conversations about Indian philosophy, some of the ideas of Quantum Physics that had seemed so crazy suddenly made much more sense" attributed to Heisenberg. Wikiquote says it is a comment made by Fritjof Capra about Heisenberg. Did Heisenberg actually share this position ( quantum mechanics and Indian philosophy)? Is it fare to attribute this quote to Heisenberg? 220.227.207.32 (talk) 04:11, 15 July 2010 (UTC)

About this quote Fritjof said "he (Heisenberg) told me something that I think is not known publicly because he never published it" in an interview (see The Tao of Physics). I could not find any other reference of Heisenberg saying this specific quote but there are several references indicating Indian philosophy had some influence on Heisenberg . - manya (talk) 05:07, 15 July 2010 (UTC)

One should be very careful about the interpretation of this. People get inspiration from a wide range of sources - but that's not the same thing as saying (for example) that quantum theory is 'based on' Indian philosophy - or that proof of quantum theory somehow validates that philosophy as being true. Inspiration is a complicated thing - often it's just an unrelated topic that provides a mental jolt that unfreezes the brain to look at different approaches to a previously difficult topic. Richard Feynman always said that his interest in bongo playing inspired some of the ideas in his quantum electrodynamics work...he definitely didn't mean that quantum electrodynamics has anything whatever to do with bongo drums or the sounds they make! Analogy is a powerful tool for understanding one topic based on an easier understanding of an unrelated topic...but an analogy isn't a causal or consequential connection between two topics, it's nothing more than some kind of vague structural similarity - and that's an important thing to bear in mind. SteveBaker (talk) 12:30, 15 July 2010 (UTC)

For that matter, Heisenberg might have been making a joke in the vein of "quantum mechanics makes a lot more sense when I'm drunk" which Capra mistakenly took seriously. -- BenRG (talk) 18:29, 15 July 2010 (UTC)

Thank you all for the replies. Ignoring these remarks, what was Heisenberg's (own) position on this Capra-type "theory"; that is on the "theory" that quantum mechanics justifies Indian ( which Indian is another question) view of the world. 220.227.207.32 (talk) 04:29, 16 July 2010 (UTC)

Bearing in mind that Heisenberg died only the year following the publication of Capra's The Tao of Physics, he might not have been very aware of it, or may not have made any recorded pronouncement of any opinion he did have. However, he did give an address in 1973 titled (in translation) "Scientific and Religious Truth", as mentioned in our article on him (last paragraph of the Post 1945 section) which also mentions a couple of books by others that cover his views in this area: these publications, if you can access them, might be of interest to you. 87.81.230.195 (talk) 07:04, 16 July 2010 (UTC)

TToP was specifically based on the bootstrap model, which was an attempt to understand hadron physics by abandoning the notion of elementary particles. The bootstrap model attracted a lot of interest for a few years, especially at Berkeley, where Capra was at the time, but it was never predictive, and it was abandoned around 1973–5 after asymptotic freedom was discovered and it became clear that the quark model was the correct model of hadrons. So any opinion a physicist might have had about the material in TToP in 1972 would probably need updating by 1976. -- BenRG (talk) 19:43, 16 July 2010 (UTC)

I happen to know that there will be a very interesting book coming out in the next year or so regarding the Capra book and other similar works that came out in the 1970s and how they were received by the physics community at that time. If you're interested in details I'd be happy to give them to you over e-mail—just use the Wikipedia e-mail function. --Mr.98 (talk) 20:27, 17 July 2010 (UTC)

Double standard

Why does it say in silver#Medicinal that people put silver dollars in their milk, while medical uses of silver#Use as disinfectant says they used sixpence? --Chemicalinterest (talk) 11:30, 15 July 2010 (UTC)

• Fixed your section links --Anon, 22:05 UTC, July 15, 2010.

My guess would be that the former was written by an American and the latter by an Englishman. HiLo48 (talk) 11:33, 15 July 2010 (UTC)

The point is that they used locally available silver coins. The exact denomination doesn't really matter. APL (talk) 15:52, 15 July 2010 (UTC)

A dollar vs. sixpence? I think this warrants a jab about national healthcare and its respective impact on the cost of medication on the various sides of the Atlantic. Nimur (talk) 16:25, 15 July 2010 (UTC)

A replacement with silver coins might be better. --Chemicalinterest (talk) 21:06, 15 July 2010 (UTC)

Resolved

ticks

whats the best way to kill a tick? yesterday we found 4 ticks around our house and on people. my brother made a contraption that electorcutes them and thats what we do now. we used to burn them with matches. whats your way to get rid of them???--Horseluv10 (talk) 11:31, 15 July 2010 (UTC)

If they are just wondering around then I would simply crush them with something. If they have latched onto a person or animal then you need to be very careful when removing them. I would suggest purchasing a specialised tick removal tool (basically a piece of plastic with a notch in it that you slide around and under the tick to remove it). It is very important to make sure you remove the whole tick and do not leave the mouthparts in the skin, where they could cause an infection. You should also monitor anyone bitten by a tick for several weeks for signs of Lyme disease. If you have any concerns, I suggest contacting a doctor. --Tango (talk) 11:40, 15 July 2010 (UTC)

If someone has been bitten by a tick, it is recommended to keep the thing in the freezer in a bag for a few weeks. If the victim in question does show symptoms, the frozen tick can be useful for doctors to analyze later. And if they are fine, there's nothing better than finding a frozen tick in your freezer months later! --Mr.98 (talk) 12:19, 15 July 2010 (UTC)

talking about crushing them, ticks have VERY hard exoskeletons and that would make them very difficult to crush. we've tried that already with unsuccessful results. but freezing a tick might be a good idea.--Horseluv10 (talk) 12:35, 15 July 2010 (UTC)

Try crushing them with the corner or a credit card or something. --Tango (talk) 12:58, 15 July 2010 (UTC)

I use needle-nose pliers. For the hard-body ticks around here, nothing less gives me enough leverage. --Carnildo (talk) 23:55, 15 July 2010 (UTC)

We use an old country remedy: rub some Vaseline all over the little buggers. As they breathe through pores on the side, they will suffocate and fall off. --TammyMoet (talk) 13:28, 15 July 2010 (UTC)

Will pool chlorine kill ticks? John Riemann Soong (talk) 14:59, 15 July 2010 (UTC)

What is pool chlorine? sodium hypochlorite, trichloroisocyanuric acid... --Chemicalinterest (talk) 16:40, 15 July 2010 (UTC)

Well I meant at the concentrations it's used at (several ppm). Like will going swimming in a chlorinated pool remove ticks? John Riemann Soong (talk) 17:16, 15 July 2010 (UTC)

Probably will suffocate it first. --Chemicalinterest (talk) 21:06, 15 July 2010 (UTC)

people say that if you try to do certain stuff to ticks like put vasceline on them, they will release lots of toxins--Horseluv10 (talk) 21:16, 15 July 2010 (UTC)

Listen, and understand. That tick is out there. It can't be bargained with. It can't be reasoned with. It doesn't feel pity, or remorse, or fear. And it absolutely will not stop, ever, until you are dead.

But seriously, all the advice above is good, except that the tick is nothing magical like above - any way to kill it will do the job and won't leave toxins unless possibly if you use some concentrated acid. SamuelRiv (talk) 02:59, 16 July 2010 (UTC)

Acid won't do anything. I tried killing a spider by putting it in acid; it just falls asleep on the surface. (Now add some sodium hypochlorite; he is dead within a few seconds). --Chemicalinterest (talk) 11:22, 16 July 2010 (UTC)

Try adding a surfactant to the acid. Then the spider would at least drown. Googlemeister (talk) 13:11, 16 July 2010 (UTC)

Chlorine kills them quickly; it is formed by the reaction between hypochlorite and acid. --Chemicalinterest (talk) 14:38, 16 July 2010 (UTC)

hiccups

why do people hiccup and how can you stop it?--Horseluv10 (talk) 11:33, 15 July 2010 (UTC)

Have you read our article, hiccup? --Tango (talk) 11:34, 15 July 2010 (UTC)

oh, didnt even think of that! silly me!--Horseluv10 (talk) 11:40, 15 July 2010 (UTC)

On the other hand, there are people who have reported hiccups lasting for years, and that nothing could stop them. ~AH1^(TCU) 18:43, 16 July 2010 (UTC)

Identify fish

Takashi Amano's website has a photograph of a fish http://www.amanotakashi.net/ (bottom left) - in one of his books I think it was described as an "Oni-demon" fish due to its similarity to a Oni (folklore). There's some more images here [4] What fish is it? 83.100.251.46 (talk) 12:23, 15 July 2010 (UTC)

Asian sheepshead wrasse (no photo). Aka bulgyhead and kodubai. --Cookatoo.ergo.ZooM (talk) 13:07, 15 July 2010 (UTC)

Thanks very much.

Resolved

83.100.251.46 (talk) 13:18, 15 July 2010 (UTC)

Speech therapy

I have recently finished my High school equivalent studies (A-levels) and am applying for undergraduate medicine in several universities. A local university is offering a Bachelor of Science in Speech Language Therapy (BSc. SLT). I want to know the future potential of such a qualification and the pay grade of Speech Therapists compared to other medical qualifications. Thanks. --119.155.0.198 (talk) 12:26, 15 July 2010 (UTC)

I assume you are asking about employment in the UK. This page at Jobs4U has some indicative salary figures. The Royal College of Speech & Language Therapists site also has a lot of useful information. Gandalf61 (talk) 12:40, 15 July 2010 (UTC)

This NHS Careers page contains some useful information (although no salary expectations). --Tango (talk) 12:50, 15 July 2010 (UTC)

I believe doctors get paid a lot more than speech therapists. 92.24.191.1 (talk) 13:15, 15 July 2010 (UTC)

They do indeed. Doctors train for much longer too. --Tango (talk) 13:49, 15 July 2010 (UTC)

which, it being illegal to practice without the entirety of that training (with no alternative), artificially limits supply as De Beers does with its diamonds. As for demand, obviously it is almost totally inelastic: I want my finger sewn back on whether it costs $80, $800, $8,000, or, if I can take that much debt on, $80,000. The resulting price is charged in the U.S.; Britain, being "commie bastards" when it comes to health care, do not obey the rules of economics, and you do not have to pay $80,000 (if you could repay that in your lifetime) to get your finger sewn back on. 84.153.255.139 (talk) 16:17, 15 July 2010 (UTC)

p.s.: if I would pay $80,000, why isn't that the price in the U.S.? (it is in fact less). It is because although I can put aside $80,000 over the next, say, fifteen years, repaying the loan, not everyone could, and so the price is lower. If nearly everyone who needed a finger sewn back on in the United States were a billionaire, with myself being the sole exception, you could rest assured that I would be asked for, say, $13 mil for the operation (if not more). I could not afford that, but the price is not set by me, but by the billionaires, since we're talking about a monopoly situation -- it is illegal for my Uncle Fred to read up on the operation overnight and do it for me for a few hundred. 84.153.255.139 (talk) 16:21, 15 July 2010 (UTC)

Part of that is because if you let your Uncle Fred do it, at best you would lose your finger anyways, and at worst you would get gangrene, or a nasty infection and die. Googlemeister (talk) 16:49, 15 July 2010 (UTC)

The US health care system isn't a free market either, though, because of the laws you mention about practising without a license. The US has regulation on one side of the market while the UK has regulation on both. That is why the UK has better healthcare than the US (there are plenty of statistics to back up that claim). --Tango (talk) 16:56, 15 July 2010 (UTC)

Well, to get that result you have to pick a definition of better and use the statistics that correspond to it. The US has "better" health care in the sense of what you can get immediately if price is no object. At least I would be quite surprised if you have statistics refuting that. --Trovatore (talk) 18:51, 15 July 2010 (UTC)

The UK has plenty of private health care that you can get immediate access to if you are willing and able to pay (or have insurance). It is no different from the US in that respect. --Tango (talk) 19:17, 15 July 2010 (UTC)

I know you can get it in the UK (though admittedly I probably wasn't thinking about it; I'm more familiar with Canada, where privately paid health care is essentially unavailable even though not technically illegal). But the question is, is it as good? My understanding is that it is not, at least at the top end. --Trovatore (talk) 21:25, 15 July 2010 (UTC)

Go for psycholinguistics then you can do speech therapy, language development, the evo-devo of the biology of language, and all that fun. John Riemann Soong (talk) 15:53, 15 July 2010 (UTC)

My mother did this track, and hated the dull repetitiveness of therapy. Get a good academic background if you're interested in the subject such that you can always combine research with therapy, or teaching with therapy. SamuelRiv (talk) 03:00, 16 July 2010 (UTC)

Starting masturbation at a very young age

How do some people learn to do it when they are as young as 5 years old (in my case) while others don't know about it until or after puberty? For me, I wasn't even taught about it but as long as I can remember, I started doing it since I was like 5 years old. I remember getting the exact same sensation of orgasm even though I hadn't ejaculated any semen then (which interestingly suggests that the ability to feel orgasm is developed much early in life, way before puberty, separately from the ability to make sperms/eggs for sexual reproduction). I'd like to know how and why people drastically differ in terms of the time period at which they self-teach masturbation (ranging from as young as 5 years old to 20 or older). —Preceding unsigned comment added by 142.58.43.84 (talk) 18:15, 15 July 2010 (UTC)

I'm not sure there will be any particular reason for it. I guess most people discover the pleasure of masturbation by chance, which means it is entirely expected that different people will discover it at different times. --Tango (talk) 18:33, 15 July 2010 (UTC)

It is perfectly normal to discover it at a young age. As a child explores the world that surrounds it, it also explores its own body, what it is composed of, what abilities it has (walking, etc.). It's natural to also discover masturbation in this way. --Ouro (blah blah) 21:22, 15 July 2010 (UTC)

Supposedly in Victorian days a slovenly Nursemaid might stimulate a baby's genitals to keep it quiet but I don't know whether that could have an effect on the child's development such as Precocious puberty. Cuddlyable3 (talk) 21:24, 15 July 2010 (UTC)

The name of an intense burst of heat and wind.

I'm not sure that this really fits within the Science category, so I apologize if this needs to be moved.

I remember reading a Wikipedia article a while ago, but I've completely forgotten the name of it. It was about a type of wind burst, for lack of a better term. I think it had an Arabic or Persian name. There was only one recorded instance of it occurring in the United States, in the 1800s -- the heat rose to shocking levels, and intense wind blew red-hot sand across California, to the point where hanging fruits were burnt and damaged on the side exposed to the wind. It drove everyone inside, where they were safe because of their adobe-walled houses (and "adobe-walled" was specifically mentioned in the article), but a man on a small ship off coast was either killed, or extremely badly burnt.

Does anyone know what I'm talking about? If someone could tell me the term so I can tell someone about the article, it'd be fantastic. If not, sorry for wasting the reference desk's time. 202.10.88.115 (talk) 20:36, 15 July 2010 (UTC)

Simoom Gandalf61 (talk) 20:40, 15 July 2010 (UTC)

::Red hot sand? Really or just a hyperbole? --Chemicalinterest (talk) 21:00, 15 July 2010 (UTC)

Could you be thinking of harmattan? If it isn't, look at list of local winds.I didn't see the question answered. --] (talk) 21:03, 15 July 2010 (UTC)

Föhn was the first one I thought of. It's in the list Chemicalinterest mentioned, but it doesn't sound very Arabic. Most parts of the world have invented their own names for such winds. HiLo48 (talk) 21:13, 15 July 2010 (UTC)

Sirocco? 62.56.49.134 (talk) 21:44, 15 July 2010 (UTC)

For the California occurrence, see Goleta, California#Geography and this article. I haven't yet found a WP article on the phenomenon other than Sundowner (wind). Deor (talk) 22:26, 15 July 2010 (UTC)

On further investigation, I think Simoom is the article that the OP is looking for. It contains the adobe-wall detail. Deor (talk) 22:32, 15 July 2010 (UTC)

Facepalm And I didn't even notice Gandalf61's answer above. Deor (talk) 13:02, 16 July 2010 (UTC)

Also take a look at haboob, heat burst, microburst, Chinook wind, derecho, Khamsin and adiabatic heating. ~AH1^(TCU) 18:38, 16 July 2010 (UTC)

Volumetric flasks

I think that I was taught that the proper way to mix a solution in a volumetric flask is to put in the stopper, hold the stopper and then swirl it around while holding it upside down. Every time I do that, though, at least when I'm using a ground glass stopper, a little bit of the solution leaks out. Is there some way to prevent this or am I doing something wrong? I've noticed that the plastic stoppers don't seem to have this problem, but I've mostly got glass stoppers and I'm sure chemists didn't just let their flasks leak before plastic stoppers came along. ike9898 (talk) 20:40, 15 July 2010 (UTC)

A ground glass stopper should not leak! You obviously have the wrong size stopper. A common error is to use a stopper marked with a single size number (e.g. 19) in a joint where there are two numbers marked (e.g. 19/22) – a 19 stopper will go into a 19/22 joint and look like it fits, but it will not be watertight. Check that the ground part of the stopper fits the whole of the ground part of the joint – you might have to search around lab drawers for stoppers that actually fit! Physchim62 (talk) 21:23, 15 July 2010 (UTC)

Rubber stoppers aren't really a good answer anyway - rubber (or even plastic "rubber substitute") reacts with too many things. Glass is fairly inert. SteveBaker (talk) 23:15, 15 July 2010 (UTC)

The plastic stoppers for volumetric flasks are usually hard PTFE, which is usually inert enough for anything you would usually use a volumetric flask for. They do have a tendency to get stained by permanganate though. Physchim62 (talk) 00:34, 16 July 2010 (UTC)

Well, I'm pretty sure I'm using the correct size stoppers, but what about the mixing technique? I've always tried to do what I was shown in an O Chem lab 18 years ago - invert and sort of swirl the bulb around. Doing it this way the flask has to stay upside down for at least several seconds. Since asking this question, I've Googled around and failed to find any mention of this mixing technique. A few sources mention inverting the flask very briefly, several times. ike9898 (talk) 00:52, 16 July 2010 (UTC)

I've heard of that technique – I was probably taught it at some point or other – but I've never used it myself and I didn't teach it when it was me doing the teaching. A little trick to remember is that it is virtually never necessary to dissolve anything in a volumetric flask, so you only need enough mixing to get a homogenous solution. That you can acheive by briefly inverting the flask a couple of times. Physchim62 (talk) 01:06, 16 July 2010 (UTC)

Makes sense, except that the more I learn about mixing, the more I believe that it takes more effort to achieve homogeneity that intuition would tell me. I think I'll just make it a practice to briefly invert, but do it many times. ike9898 (talk) 13:29, 16 July 2010 (UTC)

Quantum entanglement

Could you use quantum entanglement to send messages faster than light? --138.110.206.100 (talk) 21:18, 15 July 2010 (UTC)

No. Cuddlyable3 (talk) 21:25, 15 July 2010 (UTC)

Why not? If one particle collapses into a certain state, the other particle instantly collapses into the corresponding state, regardless of the distance between them. --138.110.206.100 (talk) 21:27, 15 July 2010 (UTC)

Isn't that precisely, exactly, why quantum entanglement is so exciting? Because it allows for faster-than-light information transfer, and hence potentially faster-than-light communication? At the least, I'd expect a reference or elaborated answer from some giving such a categorical answer on the science desk. 86.163.212.254 (talk) 21:52, 15 July 2010 (UTC)

See our article on quantum entanglement. While there is apparently a FTL state change, no useful information can be transferred without some kind of separate key, which must be transmitted normally. — Lomn 21:59, 15 July 2010 (UTC)

The collapse of the wavefunction chooses randomly among the possible states, so even though the measurement at one end allows you to predict the properties of the partner particle, the individual states presented are essentially random. Consequently, we don't know of any way to control the process, even in principle, that could convey non-random information to the other observer. There are subtleties about why different communication strategies fail, but so far we don't know any way to exploit quantum entanglement to send usable information faster than light. Dragons flight (talk) 22:19, 15 July 2010 (UTC)

Couldn't you collapse multiple particles until the number of particles with the intended state is greater than the number of particles with the other state? The other person would count the number of particles with each state and determine which is greater. --138.110.206.102 (talk) 23:11, 15 July 2010 (UTC)

How does the other person know how many particles they need to check? --Carnildo (talk) 00:05, 16 July 2010 (UTC)

(ec) Consider the classical equivalent: make some red/black playing card pairs (to use Steve's suggestion) and then look at your cards until you've seen more red than black (or more black than red). The other person, looking at their cards, can't tell when you stopped looking. The quantum case is the same. In fact, the quantum version of this experiment is the classical version. To get any peculiarly quantum predictions you need to have a choice of noncommuting bases for your measurement. That aspect of entanglement is often omitted from popularizations, even though it's the only part of the thing that's actually quantum. Instead they give you plain old classical correlation—Steve's red and black cards—presented as though it were new and amazing.

Communication via entanglement is provably impossible in mathematically rigorous formulations of quantum mechanics. The Standard Model has no mathematically rigorous formulation and it's not technically possible to prove anything about it, so maybe one could try to argue that it's an open question there. But any obvious way to do it would also work in rigorous quantum theories, and hence is already ruled out. -- BenRG (talk) 00:09, 16 July 2010 (UTC)

For some reason, this confuses a lot of people. Perhaps it's wishful thinking or willful misunderstanding - but FTL communication it ain't. If you actually read Quantum_entanglement#Concept and the following section Quantum_entanglement#Other_Interpretations, this is all spelled out very clearly - with the conclusion: "However, because the method involves uncontrollable observation rather than controllable changing of state, no actual information is transmitted in this process. Therefore, the speed of light remains the communication speed limit".

So you and a friend both have one of the two entangled particles. You measure the state of yours and the answer is "A" - and if your friend examines his, it'll be "B". He knows the state of your particle and you know the state of his. But that's no different than if you'd taken two playing cards - one red and one black, mixed them up and sealed them into two envelopes before you moved away from each other. When you opened yours and found it was red - you'd know the state of your friend's card is black...but that information doesn't allow you to communicate any new information. Since the act of examining the particle forces the entanglement to collapse - you can't even tell when the other person examined their particle. There really is no way for information (or mass or energy) to exceed the speed of light. SteveBaker (talk) 23:12, 15 July 2010 (UTC)

Read my above post. You can't control the state of each particle, but you can control whether you collapse another one or stop. Once the majority are collapsed to the state you want, stop. --138.110.206.102 (talk) 23:21, 15 July 2010 (UTC)

Yes, but the supposed recipient of the message has no way of telling how many particles you ended up collapsing -- unless you send him a message to tell him, which sort of defeats the purpose. Looie496 (talk) 23:26, 15 July 2010 (UTC)

Is there a way to tell whether a particle has collapsed without collapsing it if it hadn't? --138.110.206.102 (talk) 23:29, 15 July 2010 (UTC)

No. All you can do is make a measurement. If the particle is entangled it will collapse, but you have no way of knowing whether the result you get occurs because you collapsed the wavefunction or if the wavefunction had already been collapsed from the other end. Dragons flight (talk) 23:46, 15 July 2010 (UTC)

That's not quite accurate, DF. @138: The act of measuring the state "collapses" the uncertainty, but since the particles are entangled, the friend could tell the state of his particle without observing it by ... asking the first person what the measured state of his/her particle was! Of course, the question and answer are limited to light speed communication, so that's a dead end as well. --RexxS (talk) 00:00, 16 July 2010 (UTC)

Seems like this or something similar. hydnjo (talk) 03:07, 16 July 2010 (UTC)

What is the blue in this photo of the Moon?

from Apollo 12

What is the blue in the upper right corner of this photo of the Moon? Bubba73 ^{(You talkin' to me?)}, 21:41, 15 July 2010 (UTC)

Looks like some kind of glare. --Chemicalinterest (talk) 21:56, 15 July 2010 (UTC)

Yeah, I'd guess some sort of lens effect. Note that it doesn't match the contours of the lunar terrain that it's superimposed on. — Lomn 21:58, 15 July 2010 (UTC)

This page says "Note that the blue coloration at the top right is undoubtedly an artifact." - which isn't exactly helpful. On this page you can read what Bean and Conrad were saying to each other when the photo was taken. Pretty boring stuff, definitely not: "OMG! That alien spaceship is firing at us with it's high power blue space-laser! <bzzzzttttt>"! In this wider shot (which was two shots before that one on the same roll of film: [5] you can see that the sun was shining from above and to the right - so the odds are good that this is some kind of reflection from inside the camera or a lens flare of some kind. SteveBaker (talk) 22:37, 15 July 2010 (UTC)

The official NASA Apollo Lunar Surface Journal website indicates that for the image in question, AS12-47-6922: "The blue 'fog' is do to a dust smudge which first shows up on 6813." In fact this smudge shows up in several of the preceding and following images. AS12-47-6922 was also converted into an anaglyph with photograph AS12-47-6923: [6] You can see from the overlay that the artifact is not actually on the surface. Also, SteveBaker's dialog link is a mirror of the official listing from NASA ALSJ website. Nimur (talk) 23:11, 15 July 2010 (UTC)

Thanks, guys, that was very helpful. Bubba73 ^{(You talkin' to me?)}, 23:46, 15 July 2010 (UTC)

Is this a bunion?

Is this a bunion? http://1.bp.blogspot.com/_UaLWp72nij4/S62Y_SM84_I/AAAAAAAAFkM/aFVniqyNs4E/s1600/debra-messing-feet-2.jpg (little NSFW) 83.31.83.70 (talk) 22:01, 15 July 2010 (UTC)

Sorry - we're not allowed to answer that - you're asking for a medical diagnosis and we're specifically not allowed to provide one (see the note at the top of the page). If you are worried about it, you should consult a doctor. SteveBaker (talk) 22:21, 15 July 2010 (UTC)

No that's a scantly dressed women ;) -- Sjschen (talk) 22:56, 15 July 2010 (UTC)

Yeh, it took awhile to figure out what the OP was asking about. It would require a doctor to figure out if it's a bunion or just her natural boniness. The best bet is for the OP to read that article and take his own best guess. Or he could write a fan letter and ask. I'm sure such a letter would get a quick reaction. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:45, 15 July 2010 (UTC)

Steve, why should I consult my doctor? Do you really think that it's me on this photo? That I posted picture of myself with my tits almost out? 83.31.97.1 (talk) 23:56, 15 July 2010 (UTC)

Because: (a) You use an anonymous IP address, so we don't know whether you are this person or not (b) you can ask a doctor for a medical opinion - it doesn't have to be you that you're talking about (c) our policy about not diagnosing medical conditions requires that we suggest consulting a doctor and (d) if you're looking at that picture and you're worrying about bunions...you might need to see a doctor! :-) Either way, it doesn't matter. We aren't allowed to diagnose medical conditions - period. SteveBaker (talk) 12:13, 16 July 2010 (UTC)

What's the Polish word for "bunion"? :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:03, 16 July 2010 (UTC)

Not to be confused with the legendary figure Pole Bunion. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:14, 16 July 2010 (UTC)

Don't know why you're asking but it's pl:paluch koślawy (don't you know about interwiki links?!) Smartse (talk) 13:31, 16 July 2010 (UTC)

I must admit I have no idea if that's a bunion. but I must also admit I never looked at the feet --RexxS (talk) 00:04, 16 July 2010 (UTC)

(Not a diagnosis, and not medical advice:)When my feet looked like that, the podiatrist did surgery for bunions. Fortunately, my boobs never looked like that. (See Gynecomastia (Not medical advice)) Edison (talk) 04:27, 16 July 2010 (UTC)

The thing on her right big toe joint is of course a bunion. its bleedin obvious. —Preceding unsigned comment added by 88.104.91.109 (talk) 22:26, 17 July 2010 (UTC)

Are you sure? Bunions don't normally bleed AFAIK :-P Nil Einne (talk) 05:48, 19 July 2010 (UTC)

Chocolate Liquor

My understanding is that when the beans are taken from the tree, the are left to dry, and undergo fermentation. So, (believing that fermentation always results in ethanol) it would be logical to presume that chocolate naturally contains alcohol, without any being added. So if anybody can enlighten me to whether the alcohol is removed, or maybe even if there is a brand of alcoholic beverage from chocolate (without being added). 99.114.94.169 (talk) 23:23, 15 July 2010 (UTC)

Fermentation does not always result in ethanol. Fermentation merely means the action of microbes (yeasts, molds, and bacteria) on a foodstuff. There can be any number of products of fermentation; sometimes it is ethanol but it could be vinegar or cheese or any of a number of other compounds. In cocoa fermentation specifically, there is a two stage fermentation. Yeasts produce ethanol, which is consumed by bacteria and further modified to produce lactic and acetic acids. Coincidentally, this was covered in some detail earlier today in the "Candy" episode of Modern Marvels on History Channel, which is why I remembered it. --Jayron32 23:54, 15 July 2010 (UTC)

Funny, because I saw it too, and while I was reading your response, I noticed how similar it was to the episode... well I must of missed that part, but thank you. So, are there any alcoholic beverages using chocolate? 99.114.94.169 (talk) 23:58, 15 July 2010 (UTC)

There are, they are called Chocolate liqueurs (pronounced "lee-CURE") which is distinct from Chocolate liquor (pronounced "LICK-or"), which is a (non-alcoholic) stage in the chocolate making process. --Jayron32 00:03, 16 July 2010 (UTC)

Not only does fermentation not always produce alcohol, it also doesn't always require microbes. Black tea and salami are two examples of foods produced by non-microbial fermentation. Looie496 (talk) 03:29, 16 July 2010 (UTC)

This may be controversial. Our article on Black tea states: 'This process is also called "fermentation", which is a misnomer since no actual fermentation takes place.' My impression of salami production suggests to me that at least historically, they were certainly not sterile during their "fermentation". -- Scray (talk) 03:41, 16 July 2010 (UTC)

Foods that are "air dried" or "air cured" most certainly have access to wild yeasts and other microbes, and absolutely could be fermented. Sourdough bread is one classic example. But salamis which are hung to dry and ferment would be another. --Jayron32 04:47, 16 July 2010 (UTC)

Black tea is certainly not fermented in the microbial sense, but Post-fermented teas such as the famous Pu-erh tea of Yunnan are indeed fermented (almost composted) by bacteria and fungi. -- Sjschen (talk) 15:51, 16 July 2010 (UTC)