Wikipedia:Reference desk/Archives/Science/2010 July 26

= July 26 =

Smardale RIGS
Smardale bridge is listed on List of Regionally Important Geological / Geomorphicological Sites (RIGS) in Cumbria - does anyone know where or how I can find out why it's listed, or more info? Thanks. Sf5xeplus (talk) 00:00, 26 July 2010 (UTC)
 * Grid reference NY725055. Physchim62 (talk) 00:30, 26 July 2010 (UTC)
 * The very first Google hit for "Smardale bridge" shows a photo of the bridge, with the caption "Smardale Bridge crosses Smardale Gill.... Behind the bridge are 'Giants' Graves,' archaeological features of uncertain origin that date to prehistoric times." There are lots more links beside. Looie496 (talk) 05:45, 26 July 2010 (UTC)
 * No.No. You misunderstand, I know where it is. My question is: why is/what is it geologically important and how can I find more about the geological features that are important. Sf5xeplus (talk) 11:23, 26 July 2010 (UTC)
 * Don't forget that someone could have added it when it wasn't regionally important. --Chemicalinterest (talk) 13:14, 26 July 2010 (UTC)
 * I think your best bet is to simply ask the Cumbria RIGS Group what the criteria for the listing were (there's a "Contact us" link at the bottom of the page). Alternatively, since the group says that "site details are logged with local authorities and the County Council", you might try the county council. Deor (talk) 15:58, 26 July 2010 (UTC)

Effeminacy
What causes effeminacy in gay males? —Preceding unsigned comment added by 88.104.91.111 (talk) 06:29, 26 July 2010 (UTC)


 * Trying to answer the question inevitably opens the Nature versus nurture debate about causes. Cuddlyable3 (talk) 10:29, 26 July 2010 (UTC)


 * Probably the same thing that causes effeminacy in straight males. -- LarryMac  | Talk  12:58, 26 July 2010 (UTC)


 * Many (most?) gay males don't exhibit any more effeminacy than straight males do. Many gay males gravitate towards the hyper-masculine, others might be 'bears', others don't behave any different from anybody else.  It's largely a social thing, mixed with whatever makes the person comfortable.  So if we narrow your question down to "what causes effeminacy in the small percentage of gay males who exhibit a marked tendency towards effeminacy?", then Cuddlyable3 and LarryMac's answers have it covered. 76.105.238.158 (talk) 00:32, 27 July 2010 (UTC)

Non-scientific answer: because the effeminate ones are cool, sociable, expressive and not shy. So they tend to be popular and more visible. John Riemann Soong (talk) 03:22, 27 July 2010 (UTC)

They purposely do that so people know their gay. there is no other explanation.--Horseluv10 11:55, 27 July 2010 (UTC) —Preceding unsigned comment added by Horseluv10 (talk • contribs)


 * Why do straight effiminate males do it then? And why don't the other gay males bother? And why do some gay effiminate males stay in the closet for so long? And what's wrong with the plenty of other explainations like the ones above? Nil Einne (talk) 21:34, 27 July 2010 (UTC)
 * What possible meaningful scientific answer do you imagine you could get for the above questions? Ask your self why YOU behave the way you behave? Why you are attracted to (presumably) girls instead of boys? If you can come up with a more meaningful answer then "because they're hot", and you aren't allowed to cheat by saying "millions of years of evolution" because that's something you are told by others, I'm sure you aren't thinking "I'm sure glad evolution has made me attracted to girls so we can have lots of offspring" when you admire someone you fancy. Human behavior is probably one of the most complex subjects you can study and people spend lifetimes trying to understand and explain it, often getting it totally wrong. It doesn't help that there are a LOT of errors and misconceptions in "common wisdom" about psychology. Vespine (talk) 23:30, 27 July 2010 (UTC)
 * I'm pretty sure Nil was directly and exclusively responding to Horseluv's simplistic and dogmatic statement. 86.164.66.83 (talk) 02:39, 28 July 2010 (UTC)
 * Yeah that makes more sense reading it again, sorry my rhetorical detector wasn't functioning correctly.. It's precisely that dogma around this subject that frustrates me, perhaps a little too quickly. Part of the reason for that is Nil's questions would NOT be the most ignorant questions I've ever heard about sexual preference if he had been serious.Vespine (talk) 05:00, 28 July 2010 (UTC)
 * Yeah 86 is correct. No problem about the confusion since as you may have guessed I too dislike silly statements about sexuality. You are correct that I'm heterosexual in any case. Nil Einne (talk) 09:53, 28 July 2010 (UTC)
 * This isn't a comment on your statement, just an interesting thought I've had, that when I answer people who "question" homosexuality I honestly have to fight the urge to say that I'm hetrosexual, because I can almost feel the people on the other end thinking "oh he's probably gay". But I know pointing out I'm hetro won't change their opinion anyway so unless they ask I make it a point not to mention it. (I know that's not what you were doing).. The funny part is that I think there is a real similarity to racism, now there is such a stigma around racism that I don't even feel comfortable drawing that analogy but maybe that's more reason to do so. I NEVER feel the need to point out that I'm white, I believe one day we'll live in a world when no one feels the need to point out they are hetro. Imagine these days someone asking what it "feels like" to be black, as if it is "different" from being a normal human. Unfortunately there are stsill many people who feel this way about homosexuals, but I also believe they are a dying breed. Vespine (talk) 00:03, 29 July 2010 (UTC)
 * One scientific paper which I read suggested the idea that there are many (epi)genetic factors which contribute to the "feminine" (gentle?) traits of the male and that the ownership of some of these factors make their benefactor a better mate by ensuring an appropriate response to their fragile partner and offspring. Since our reproductive systems rely on random homologous recombination, it possible that in some cases, an individual inherits more or less of these characteristics than average and as a result become overly masculine or overly feminine for optimum reproductive value. On top of this however, you have the confounding environmental (including cultural) aspects already alluded to above. --Seans Potato Business 23:00, 28 July 2010 (UTC)

A 100 W light bulb emits light with a wavelength of 575 nm
How many photons leave the filament of the globe in 1 second? Basically I have no idea how to do the question. I can convert the wavelength to frequency $$f=\frac{c}{\lambda}=\frac{3\times 10^8}{575\times 10^{-9}}=5.21\times 10^{14} Hz$$ and then I can convert that to energy $$E=hf=6.63\times 10^{-34}\times 5.21\times 10^{14}=3.46 \times 10^{-19} Joules$$ if that helps --220.253.172.214 (talk) 10:10, 26 July 2010 (UTC)
 * Since it is a filament lamp the filament emits a range of wavelengths like a black body i.e. not only at 575 nm, though that may be the strongest radiation. Have a look at the referenced article. Cuddlyable3 (talk) 10:25, 26 July 2010 (UTC)
 * I think this is just a homework question ;) You're right that the situation is not physically realistic, but the same goes for many such problems. Physchim62 (talk) 10:35, 26 July 2010 (UTC)
 * Hint: How many Joules does a 100 W light emit in 1 second? Dragons flight (talk) 10:29, 26 July 2010 (UTC)
 * 100 Joules. Are you suggesting that I need to make the calculation $$\frac{100}{3.46 \times 10^{-19}}=2.89\times 10^{20}$$?--220.253.172.214 (talk) 10:52, 26 July 2010 (UTC)
 * Don't leave out the units! Besides being a requirement for physics calculations, making sure the units match is an excellent way of checking that your calculations are right. (In many cases if you don't know the formula, simply making the units correct will automatically give you the correct formula. This doesn't always work, but it works often enough to be a good first try for an unknown calculation.) Ariel. (talk) 13:47, 26 July 2010 (UTC)
 * Even bigger hint: what is the definition of power (which is measured in watts)? You calculation of the energy per photon is correct. Physchim62 (talk) 10:35, 26 July 2010 (UTC)

Bone Weight
What is the collective weight of all the bones (bones only) in an average human adult. Jon Ascton   (talk)  13:19, 26 July 2010 (UTC)
 * There's some basic figures at the bottom of this page, other sources quote a figure of 10-20% of total weight (presumably for a non obese person).This  gives 13% of body weight.  87.102.43.171 (talk) 13:39, 26 July 2010 (UTC)
 * Living human, or dry bones? (Not that I know the answer, but there is a large weight difference between the two.) Ariel. (talk) 13:49, 26 July 2010 (UTC)


 * Actually, I read somewhere today that it is about 12 pounds. (10 for females). I doubt it.  Jon Ascton    (talk)  14:09, 26 July 2010 (UTC)

Are strings matter?
I'm talking about the objects that make up quarks, not the things you use to tie your shoe with. Since they are 1 dimensional structures, it made me think if they are really matter or energy. Of course I'm aware that matter and energy are related (E=mc2) but, is it fair to say that the line is kind of blurred at that level? 148.168.127.10 (talk) 14:04, 26 July 2010 (UTC)
 * First of all, it is important to note that string theory doesn't have any significant evidence in favour of it (so it's a bit of a stretch to even call it a theory, it's just an idea). Assuming string theory is correct, then it doesn't really make sense to distinguish between matter and energy at the scale of individual strings. Photons are made out of strings in the same way quarks are and there isn't really any difference between those strings other than the way they vibrate. --Tango (talk) 14:35, 26 July 2010 (UTC)
 * What determines wether the particle has mass is the vibrational pattern of the string, not the string having mass itself, for example a photon is massless because it has a different vibration than quarks do even though they are both 1 dimensional vibrating strings according to string theory.--74.67.89.61 (talk) 14:50, 26 July 2010 (UTC)
 * Just to comment on the distinction between matter and energy: One shouldn't say that "something is energy" as if energy were something material or substantial; it is not. The correct way to put it is "Matter has energy", and the (misnomed) equivalence between matter and energy means that matter has energy even when it is at rest. So photons and strings will have energy, but they are not energy. Whether you want to call photons and strings "matter" depends on whether you want matter to be made of particles with mass or whether you accept massless particles, too. --Wrongfilter (talk) 10:02, 27 July 2010 (UTC)
 * So then what is energy? 148.168.127.10 (talk) 12:15, 27 July 2010 (UTC)
 * See energy for a long discussion of that very question. --Mr.98 (talk) 12:37, 27 July 2010 (UTC)
 * Oh sure, I know about that. I just meant within the context of what he was saying. I suppose we can't call any object energy then. Photon is not matter or energy, but it has energy. What about the four fundamental forces? Can we call any of those energy? 148.168.127.10 (talk) 15:53, 27 July 2010 (UTC)
 * Actually photons ARE energy. So is mass - mass does not contain energy - it is energy (and energy is mass, they are not just interconvertable they are two words for the same thing, but each has a different emphasis). The forces are not energy, but they do transmit energy, so while in transit they could contain energy. Ariel. (talk) 01:25, 28 July 2010 (UTC)
 * If they were the same thing, then we could simply throw out one of the terms and only use the other; much more economical. No, conceptually, mass and energy are very different things. Mass (that is rest mass) is an intrinsic, unchangeable property of a material particle; as such, mass is independent of the frame of reference. Energy is a quantity that describes the state (of motion, for instance) of a particle or physical system. It is a mathematical function that has properties which make it extremely useful to describe the state and behaviour of real physical systems; and energy depends on which frame of reference you choose. --Wrongfilter (talk) 09:41, 29 July 2010 (UTC)
 * That is incorrect. Mass also depends on the frame of reference, and energy might be invariant. For example chemical energy, or potential nuclear binding energy (the energy that the sun releases) are both invariant, and they show up as mass of course, even though they are "energy". Temperature and electric charge are also invariant (yes electric charge is energy - potential energy). Actually the only that is not invariable is kinetic energy. As you drill down you will find there is no intrinsic mass - all the mass is actually the result of potential energy of one kind or another. There is a reason that particles are weighed in electron volts (supposedly a measure of energy) instead of grams. Mass and energy are the exact same thing, and the only reason we use two words is historical. And now that we have two words we give them different emphasis. Ariel. (talk) 16:04, 29 July 2010 (UTC)
 * We could probably go on for a long time, so this'll be my last comment. Mass: Note that I referred to rest mass as the intrinsic property of a particle. Rest mass is the invariant length of four-momentum (the time component of which is energy - making it very clear from a mathematical point of view that energy and mass are different things). Temperature: When measuring temperature one doesn't take into account centre-of-mass motion. This is of course irrelevant because $$T=\partial U/\partial S$$ and entropy doesn't depend on bulk motion (and vice versa). Chemical/binding energy: You seem to suggest that I dispute the validity of E=mc2 - of course I am not. But that equation doesn't imply that the two are identical concepts. I would like to see a reference for your claim that "electric charge is energy". I would also like to see a reference for the claim that "mass is ... the result of potential energy" - have you solved the problem of the origin of mass? --Wrongfilter (talk) 17:53, 29 July 2010 (UTC)

soundwaves
Is it possible to view a soundwave in 3D? So for example would it be possible to develop a software that shows a soundwave from front on? —Preceding unsigned comment added by 91.103.185.230 (talk) 15:51, 26 July 2010 (UTC)
 * You could have software that shows 2d sections through a soundwave. More complicated solutions could include using transparent colour or exaggerated refractive index to visualise the soundwave. However note that high frequency sounds have short wave lengths eg 3.3kHz has only a 10cm wavelength. The problem with 3d visualisation of room full of soundwaves is that it would be looking through fog - also from front on you would be looking through pressure wave peaks and troughs - as the sound wave propagates itself there would be very little or no difference over time in the appearance (from front on). 87.102.43.171 (talk) 16:28, 26 July 2010 (UTC)
 * Showing 'isobars' of soundpressure level would be a lot easier - again using transparent (coloured) surfaces to visualise the sound level at different positions in space.87.102.43.171 (talk) 16:31, 26 July 2010 (UTC)


 * We regularly encounter this problem during full wave equation modeling for seismic imaging. (I'm sure RADARs and SONARs could have similar visualizations, but their data is less commonly visualized in a full 3D sense - in seismic imaging, the final desired result is a visualization of the entirety of a 3D volume, including its interior).  Because the 3D wavefront is, well, three-dimensional, trying to render it on a 2D screen means you have to makes some tradeoffs.  Many options exist for displaying the actual wavefront - you can pick an isosurface (i.e., interpolate one surface such that each point (X,Y,Z) has the same acoustic amplitude or phase) and render it in 3D; you can render a cube, and use a unique user-interface to select planar cross-section views; you can render an animated movie that traverses through one or more axes.  Or, you can process the results of the acoustic wave, and instead of visualizing the wavefront, you can image some derived parameter - e.g. reverse time migration, where the results are correlations of the acoustic wavefront with a time-reversed version of the recorded echos.  You can visualize the 3D acoustic wavefront in the fourier domain, or some other transform domain, where its 3D characteristics collapse along one or more dimensions.  Every one of these approaches comes with difficult tradeoffs that boil down to, ultimately, you can't completely represent a complicated 3D structure on a 2D viewing screen.  We have some peripherally related articles, volume rendering, tomography, and so on, that explain the difficulty of imaging a 3D structure.  Nimur (talk) 20:15, 26 July 2010 (UTC)

Thermodynamics what-if
You have a box made out of a material which is very rigid and has a low thermal expansion coefficient. It is filled to the brim with water at room temperature. Suddenly you thrust it out of the airlock of your spaceship into the vacuum of space which is a couple of degrees above absolute zero. Because the box material conducts heat, the heat energy of the water leaves through the box and the water starts to cool down. When the temperature of the water gets to the freezing point, since water is one of the different materials that is less dense as a solid than it is as a liquid, the water begins to be under pressure as it pushes on the box. Say the box held rigid. It seems to me this pressure would have an effect of increasing the water temperature so it would go back to liquid. So would the water in the box in that frigid environment stay liquid or form some denser-than-normal ice? 20.137.18.50 (talk) 16:35, 26 July 2010 (UTC)
 * It would stay liquid for longer, i.e. at a lower temperature, but eventually it would still freeze. Keep in mind that the lower density of ice is only around the freezing point. Eventually it starts contracting like other materials, this article suggests that that temperature is 200K (about -70c) - see the graph. But keep in mind this graph was made at ambient pressure. Inside your box the pressure will be much higher which will influence things. Ariel. (talk) 16:48, 26 July 2010 (UTC)
 * Freezing point doesn't vary much with pressure (unlike boiling point), so it wouldn't stay liquid at a significantly lower temperature. --Tango (talk) 17:02, 26 July 2010 (UTC)
 * If you increase the pressure on a gas, it warms up, but I'm not sure the same is true of a liquid. Liquids are pretty much incompressible, so I don't think they would change temperature much. Regardless, as Ariel says, the water would eventually cool to the point where ice is denser than liquid water, at which point it would definitely freeze. --Tango (talk) 17:02, 26 July 2010 (UTC)
 * At equilibrium, the pressure inside the box will be lower than when you started, because the density of (normal) ice is higher than that of liquid water at low temperatures. While the water is cooling down, the pressure will be very much higher (but I'm assuming you want us to consider an infinitely rigid box). Physchim62 (talk) 17:15, 26 July 2010 (UTC)


 * I think I need to slightly correct what Tango said above - freezing point does change with pressure for materials like water that change volume on freezing. Since water initially expands on freezing increased pressure lowers the freezing point (described in general by Le Chatelier's principle) .. Since both water and ice are very incompressible even a small amount of (normal) ice formation would cause a very massive increase in pressure.
 * There are denser forms of ice - I don't know if the conditions here would be sufficient to cause its formation over normal ice - though I would guess it's likely.87.102.43.171 (talk) 17:34, 26 July 2010 (UTC)
 * Phase-diag2.svg This phase diagram seems to show that the freezing point of water changes less with changes of pressure than typical substances (although water does at least change in the right direction). Both the solid and dashed green lines are pretty close to vertical, so the change is pretty small. --Tango (talk) 18:08, 26 July 2010 (UTC)
 * water expands about 10% on freezing, the bulk modulus of ice is ~1010Pa - so to compress ice to the same volume of water would require about 1000MPa of pressure. In fact this is beyond the pressure for which normal ice exists - so one of the more dense forms of ice is formed. There's a similar discussion (from which I got the compressability data from) here
 * The same link references this page which has a phase diagram which extends beyond that given right - It looks like ice V or VI would be formed at 0C at these pressures. However if the cooling was rapidly to 0K and not 0C all this is not relavent.87.102.43.171 (talk) 19:34, 26 July 2010 (UTC)


 * I got a very rough figure of 1degree change in freezing point per MPa (ie 0.1 degree C per bar/atmosphere) - no idea how accurate that is.87.102.43.171 (talk) 20:44, 26 July 2010 (UTC)
 * That will only be accurate near a specific temperature (probably 0 deg C). It can't be accurate everywhere, otherwise the freezing point at 300MPa would be below absolute zero, which is obviously nonsense. --Tango (talk) 21:39, 26 July 2010 (UTC)


 * You are essentially asking about freezing water at constant density (i.e. by not allowing the water expand as it freezes). Assuming an sufficiently rigid container to counter the large pressures involved, I would expect to see a combination of normal ice and one of the high density ices such that the density of the mixture stayed constant. Dragons flight (talk) 18:28, 26 July 2010 (UTC)


 * Right.  Note that below about 250K there is no stable liquid form at any pressure, so the result is bound to be ice of some type. Looie496 (talk) 18:34, 26 July 2010 (UTC)


 * Looking into this further, what would happen, I believe, is that the water would remain liquid as it cooled down to 250K, with the pressure rising steadily to over 200 million atmospheres. Then it would freeze into a mixture of ordinary ice and altered phases of ice.  As it continued to cool, it would evolve through several combinations of phases, with the pressure slowly dropping but remaining in the hundreds of millions of atmospheres.  As it approached absolute zero, you would end with a mixture of about two parts ice XI to one part ice IX -- assuming that the container was totally filled with water at the start and totally nondeformable. Looie496 (talk) 19:55, 26 July 2010 (UTC)
 * I think that is almost but not quite right - ice can form at -1C and the pressure increase. At 20% normal ice (at -1C) the pressure would be 200MPa and then other forms of ice could form. the figures in the last sentence may be quite far out Nevertheless there would definately be normal ice in the box below 0C below 200MPa (above 250K) 87.102.43.171 (talk) 20:07, 26 July 2010 (UTC)
 * I think you meant 200million pascal, not atmospheres87.102.43.171 (talk) 22:15, 26 July 2010 (UTC)

Human magnetoception
What is the current status of human magnetoception research? The magnetoception article lists research from 2007.  Is it bunk or is there something to it? Viriditas (talk) 16:37, 26 July 2010 (UTC)
 * The article Magnetic resonance imaging contains an uncited note that Volunteers report a twitching sensation when exposed to rapidly switched fields, particularly in their extremities. Cuddlyable3 (talk) 17:00, 26 July 2010 (UTC)
 * The scholarly consensus (e. g., ) is still that humans can't detect the Earth's magnetic field, the cited article notwithstanding. MRI involves fields stronger by many orders of magnitude, so a moderate sensitivity to them wouldn't mean all that much. Looie496 (talk) 18:17, 26 July 2010 (UTC)
 * A human would be able to magnetically detect a magnetar from a good long distance off, since at 1000km away, the magnetic field is lethal. It's not strictly relevant; I just mention this fact whenever I can. Paul (Stansifer) 03:00, 27 July 2010 (UTC)

Westons Mill Pond
Westons Mill Pond is a dammed section of the Lawrence Brook in New Jersey. Would it be included in WP:RIVERS? --Chemicalinterest (talk) 17:28, 26 July 2010 (UTC)
 * There is also WikiProject Lakes. Rmhermen (talk) 19:17, 26 July 2010 (UTC)
 * You could ask at Wikipedia_talk:WikiProject_Rivers. Falconus p t   c 04:21, 27 July 2010 (UTC)

culturing cells on conductive cover slips
I think my group is using conductive indium tin oxide cover slips for electric field experiments. However, my group doesn't know what happens if you culture epithelial cells on it -- any predictions? Would poly-L-lysine coating -- used for helping cells adhere -- ruin the conductive properties, or no? John Riemann Soong (talk) 18:53, 26 July 2010 (UTC)
 * Google suggests that others have managed it http://www.google.co.uk/search?sourceid=chrome&ie=UTF-8&q=polylysine+indium+tin+oxide eg (at least compatable), here google books (must be still conductive) seems to suggest that a polylysine coated indium tin oxide film was successfully used in a reduction (hence still conductive)
 * The issue I can see would be if polylysine (basic) reacted with the indium tin oxide - if the indium tin oxide film is very thin (ie 1 atom) you could end up stripping that film by complexation with the polyamine... However I imagine the film will be much thicker.
 * I have no idea about culturing cells on indium tin oxide - if indium or tin is toxic to your cells then that could be a problem - beyond that no idea. It's not clear why a conductive glass slide is needed - wouldn't anodised aluminium be just as good for culturing cells and doing field experiments?87.102.43.171 (talk) 21:28, 26 July 2010 (UTC)
 * Well it's what my group has. Is anodised aluminum see-through? :S I'll probably try using these cover slips tomorrow. John Riemann Soong (talk) 22:33, 26 July 2010 (UTC)

Plant ID request
We saw this plant at Disneyland and was wondering what it is. Any help from an editor out there? Thanks, Alanraywiki (talk) 19:50, 26 July 2010 (UTC)


 * Impatiens, possibly. Maybe one of the New Guinea impatiens cultivars, see Impatiens hawkeri --Dr Dima (talk) 20:38, 26 July 2010 (UTC)


 * Thank you so much. I feel a little dumb because we have some impatiens in our yard, but this looked a little different to us.  I appreciate your time in answering.  Alanraywiki (talk) 22:00, 26 July 2010 (UTC)
 * Please place all further responses to this question on Reference_Desk/Miscellaneous, where this question was also posted. Falconus p t   c 04:30, 27 July 2010 (UTC)

Help me identify these intercellular bridges, follow-up?
I've put up some of my images at User:John Riemann Soong/intercellular bridges. I'm trying to puzzle out what kind of intercellular bridges these are. These bridges are between A549 lung cancer cells. Help is appreciated!

for background, most of the white things that don't appear to change appearance with rotations are vesicles, not gold nanorods. Particles that go black-white-black or "wobble" are gold nanorods. I excluded most of the video of course as they are much too big, but I can upload huge (~30 MB) animated gifs if necessary. A brief description of what happened on each day is on the page I linked to.

I've been reading this paper to try to help me identify these bridges. Do any of them consist of membrane nanotubes at least internally? I don't think I have any "tunneling nanotubes" right? Am I observing type I epithelial bridges, or just mere filopodial bridges? John Riemann Soong (talk) 23:52, 26 July 2010 (UTC)