Wikipedia:Reference desk/Archives/Science/2011 December 7
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December 7
editIsn't sputum full of proteins?
editShould evolution work towards more acceptance of directing sputum into the stomach? Imagine Reason (talk) 02:18, 7 December 2011 (UTC)
- Evolution is not an intelligent being. It doesn't work towards anything. -- kainaw™ 02:28, 7 December 2011 (UTC)
- Not all proteins are good for consumption. Yes, there are good proteins, but, for example, salmonella isn't something you want to direct into your body. -- kainaw™ 02:38, 7 December 2011 (UTC)
- What do you mean "more acceptance"? Do you mean a better biological mechanism for directing sputum into the stomach, or social acceptance of eating sputum? --Colapeninsula (talk) 10:36, 7 December 2011 (UTC)
- Well, we don't like the taste of sputum, and everyone just spits it out if able. Imagine Reason (talk) 23:51, 9 December 2011 (UTC)
Yeah, most saliva does end up in the stomach rather than being spat out or dribbled. Graeme Bartlett (talk) 12:11, 7 December 2011 (UTC)
Copernican Model
editIt seems like Copernicus' hypothesis of a heliocentric universe wasn't really supported by any observations (pre-Galileo). That is, all observations of the universe were adequately explained by the Ptolemaic model. So why did many scientists prefer the Copernican model? — Preceding unsigned comment added by Trimbler00 (talk • contribs) 06:47, 7 December 2011 (UTC)
- Well, for one, simpler is better — it did away with the need for epicycles and other complicated reasoning for the bizare apparent motion of the heavenly bodies. Plasmic Physics (talk) 08:37, 7 December 2011 (UTC)
- Copernicus' model had epicycles. It was Kepler who did away with them by concluding that planets moved on elliptical orbits. If I'm not mistaken, the Copernican model was not even better at describing the observations than the Ptolemaic model. Kepler's model was. --Wrongfilter (talk) 09:06, 7 December 2011 (UTC)
- The Kepler model was not even strictly heliocentric because the Sun is located at a focal point rather than at the center of the elliptical planet orbits. The Newton model doesn't have a center at all. Bo Jacoby (talk) 09:19, 7 December 2011 (UTC).
- Copernicus' model had epicycles. It was Kepler who did away with them by concluding that planets moved on elliptical orbits. If I'm not mistaken, the Copernican model was not even better at describing the observations than the Ptolemaic model. Kepler's model was. --Wrongfilter (talk) 09:06, 7 December 2011 (UTC)
- The truth is most scientists did not prefer it until Galileo's observation of the phases of Venus, which is the first piece of anything that was totally incompatible with the Ptolemaic model. Even then it took a long time for heliocentrism to really catch on. The discussion here is pretty good. It's also worth noting that there were other alternatives between pure Ptolemaic and pure Copernican — even after Galileo, many astronomers (notably the legions of Jesuit astronomers employed by the Church) preferred the Tychonic system, which at the time was observationally indistinguishable from a heliocentric model. The few scientists who did support Copernicanism, without much evidence, did so for philosophical reasons, not scientific ones, to put it very simply. Sometimes philosophical reasons turn out to be right. Sometimes they don't. Kepler liked heliocentrism because he believed the Sun was the most powerful thing in the universe. That's not correct at all, but it did lead him down a "more correct" path from the view of the present (even if much of his reasoning is completely batty). (Kepler in general is a good case study in how a completely insane set of beliefs can still get one to extremely useful science.) --Mr.98 (talk) 13:31, 7 December 2011 (UTC)
- A large part of the answer (why some people preferred the heliocentric model without scientific reason) is Hermeticism. This is also largely why the heliocentric model (or at least most of the works arguing for it) was suppressed by the Church from shortly before Galileo (who certainly had many hermeticist contacts, and used hermetic terminology) started arguing for it. And given that the Hermeticists believed that widespread adoption of the Heliocentric model would be followed by complete rejection of the Church, and that this had actually already led to violence, one can at least sympathise with why the Church would want to suppress it, for a while. 86.164.79.174 (talk) 09:41, 8 December 2011 (UTC)
Powering civilization with something other than electricity
editAre there any other potential candidates that may replace electricity? ScienceApe (talk) 07:04, 7 December 2011 (UTC)
- Would you care to explain? I honestly have no idea what you are considering. Plasmic Physics (talk) 08:33, 7 December 2011 (UTC)
- Burning wood and using (water- or wind-) mills. --Lgriot (talk) 09:00, 7 December 2011 (UTC)
If that is indead what ScienceApe is considering, then no. Plasmic Physics (talk) 09:05, 7 December 2011 (UTC)
- You only have to look back 100 years to see that we managed very well before the widespread use of electricity. See energy development.--Shantavira|feed me 09:33, 7 December 2011 (UTC)
- Photonics may replace electronics in some applications, but it is still dependent on electricity.
- I guess potentially you could use anti-electricity where positrons in anti-matter wires replace electrons, but it seems kind of pointless.
- On the other hand, clockwork was very once popular; the clockwork gramophone is the nearest mechanical equivalent of the iPod, and you can also make clockwork timepieces, toys, and even sort of cars[1]. The hand-cranked mechanical adding machine is similar. --Colapeninsula (talk) 10:48, 7 December 2011 (UTC)
- You can distribute power mechanically via drive wheels, belts and chains. This is quite inconvenient and dangerous. An alternative might be pneumatics - just provide pressure lines, and connect your pneumatically driven appliances. In theory, you could even generate heat (via friction), and building a fridge should be very easy (just use the cooling effect of gas expansion). You can have "fuses" to protect you from overpressure, and also to protect the network from someone drawing too much pressure from the system. I'm not convinced all this is practical for all of civilisation, but its fun as a thought experiment. --Stephan Schulz (talk) 11:13, 7 December 2011 (UTC)
- Vladimir Nabokov's novel Ada or Ardor: A Family Chronicle is set in alternative universe in which hydraulics has replaced electricity. I don't think that it would actually work, though. Deor (talk) 13:36, 7 December 2011 (UTC)
- Lighting was the killer ap for electricity, not sure how hydraulics would provide that. 75.41.110.200 (talk) 16:21, 7 December 2011 (UTC)
- Before electricity there were widespread gas networks used for gas lighting, although it's not as convenient as electricity. --Colapeninsula (talk) 17:58, 7 December 2011 (UTC)
- Lighting was the killer ap for electricity, not sure how hydraulics would provide that. 75.41.110.200 (talk) 16:21, 7 December 2011 (UTC)
- Vladimir Nabokov's novel Ada or Ardor: A Family Chronicle is set in alternative universe in which hydraulics has replaced electricity. I don't think that it would actually work, though. Deor (talk) 13:36, 7 December 2011 (UTC)
- You can distribute power mechanically via drive wheels, belts and chains. This is quite inconvenient and dangerous. An alternative might be pneumatics - just provide pressure lines, and connect your pneumatically driven appliances. In theory, you could even generate heat (via friction), and building a fridge should be very easy (just use the cooling effect of gas expansion). You can have "fuses" to protect you from overpressure, and also to protect the network from someone drawing too much pressure from the system. I'm not convinced all this is practical for all of civilisation, but its fun as a thought experiment. --Stephan Schulz (talk) 11:13, 7 December 2011 (UTC)
I'm trying to think outside the box a little. Like if we were to encounter an alien civilization, would they power their civilization with electricity? Is this the only way? Is there anything else that would work? If we were to make a robot that could perform all of the basic functions that a human could perform (walking, running, grabbing, pushing, pulling, etc), it would be powered by electricity. But animals can do those things being powered by ATP... I think. Is that more efficient? Can you run an entire civilization on ATP? Stuff like that, just brainstorming what else might be possible. ScienceApe (talk) 16:21, 7 December 2011 (UTC)
- In Neal Stephenson's lovely novel, The Diamond Age, the only infrastructural feed into most residents is a supply of base matter that universal nanotech assemblers can then turn into whatever one might need. It's an interesting idea. It wouldn't get rid of a need for electricity, but it seems to fit into your thinking outside the box idea. --Mr.98 (talk) 17:29, 7 December 2011 (UTC)
- I like Steampunk. I have seen many non-electric power transmission systems used in industry to transmit power from a vehicle to a tool (see Hydraulic rescue tools, or from a compressor to a machine elsewhere in a plant, or to store energy in a device. Hydraulics is an excellent alternative to electricity for many applications at the present time, to transmit power for a few meters. See Hydraulic power network. Hydraulic motors work very well from hydraulic lines, with excellent power at a small size and weight compared to electric motors. Many cutting tools use a hydraulic line to power an extremely powerful but small and lightweight tool, where an electric motor or solenoid would be massive to provide the same force or torque. Some Phonographs in 1890 had a water motor, with a hose running from the tap and another back to the sink. The energy ultimately came from the city water works. Springs (wound by electric motor, or by hand crank during a power outage) still provide a large amount of stored energy, even in electric substations, to trip and reclose breakers. Everything still performs its current interrupting or reclosing function even if all the electricity abruptly fails. Compressed air is also used as stored energy on high voltage circuit breakers to provide multiple trip and close operations during a power interruption, without relying on a station battery which is all too often impaired. Oil hydraulic lines are less subject to freezing than the moisture in compressed air lines. Cables convey power from the engine of a crane to loads way up in the air, and commonly operate elevators, with reels typically operated by electric motors, but pre-1900 there were steam powered cable operated elevators in some large buildings. Rotating shafts work very well, allowing one prime mover (water wheel, diesel, steam) to power the big overhead shaft with each tool or machine in a factory having its own drive belt. These powered industry worldwide for decades, from early in the industrial revolution through perhaps the 1920's, though small electric motors on individual machines or tools proved to be safer and possibly more efficient when only part of the machines needed to operate. Steam power certainly has been useful, but for more than short distance it would require advances in insulation to reduce the heat loss and condensation in the supply lines. A 1904 article compared several power transmission systems for use in mines to drive pumps, and stated 70% efficiency for electrically driven pumps, 20% to 40% for compressed air, less than 55% for steam power pumps in main mineshafts. Steam was still in wide use, generated at the surface and sent down insulated lines to the pumps, which then raised water hundreds of feet. A 1897 book "Hydraulic machinery" by Robert Blaine compared losses for various power transmission system for 1 to 20 miles. Considering 1000 horsepower sent in, the loss in a 20 mile run for hydraulic (water under pressure) (at 700 psi) is 25.4%; for electric (at 2000 volts) is 31.2%. Electricity did better at 2000 volts than at 700 volts, where it had a 95.2% loss. Hurrah for transformers! Electricity wins for long distance transmission if the voltage is raised high enough and the current is thus made small enough to minimize losses. But the book cited says (Page 369) "However, in towns, and for comparatively small distances, the hydraulic system compares very favourably with any other as regards efficiency and supplies probably the best means of working lifts, cranes and other machines of that kind." A practical objection to long distance hydraulic transmission is the large number of joints which have to be maintained free of leaks, the bulkiness and cost of the pipes, and the danger of the water freezing. An 1886 reference compared power transmission by electricity, compressed air, water acting as a hydraulic fluid, and cables carried on overhead pulleys. Assuming a steam engine as prime mover at the sending station, the hourly cost (per horsepower) of 100 horsepower at 20 kilometers was calculated at 0.480 franc for electricity, 0.997 franc for hydraulic, 0.666 franc for compressed air, 1.321 franc for elevated drive cables over pulleys. Cables and pulleys were said to be the most cost-effective system for up to one kilometer, where the costs were 0.202 for electricity, 0.272 for water under pressure, 0.347 for compressed air, and 0.165 for cable over pulleys. Steam and rarified air were said to be ineffective for long distance. Edison (talk) 21:49, 7 December 2011 (UTC)
- Well, hypothetically, you only have a few choices; to "power" something you need energy. Here's a non complete list of Forms of energy or maybe even Fundamental interaction? This shows that gravity is probably out, being so much weaker then electromagnetism, but Strong interaction could be a contender being a couple of orders of magnitude more. I suppose that would mean that every device has a nuclear reactor in it, but to this date, all our nuclear reactors do is convert energy to electricity by various means. I don't know how you could harness and use strong force more directly, but I suppose I wouldn't assume it's impossible, given some crazy futuristic technology. Maybe appliances in 500 years time run directly on fusion reactors. Vespine (talk) 00:29, 8 December 2011 (UTC)
- I guess maybe you could replace computers with something like the Analytical Engine... Whoop whoop pull up Bitching Betty | Averted crashes 00:28, 8 December 2011 (UTC)
- Pneumatic tubes seem like good candidates for transport. ~AH1 (discuss!) 01:23, 8 December 2011 (UTC)
- A few months ago on Ref Desk I cited the history of pneumatic tubes. There were underground tube systems in large cities in the late 19th century, between freight terminals and post offices, moving many tons a day of such mail pouches as would fit in the tubes, far faster than surface transit, and for fair distances of perhaps a mile, if memory serves. But such a system of tubes is an information transmission system, more akin to an "internet" than to a power transmission system, unless you subscribe to the view than "knowledge is power." Edison (talk) 02:40, 8 December 2011 (UTC)
- Pneumatic tubes seem like good candidates for transport. ~AH1 (discuss!) 01:23, 8 December 2011 (UTC)
- (un-indent) In case nobody noticed, the OP specifically asked about what could REPLACE electricity in the future -- so the defining criteria is not that it be merely an ALTERNATIVE to electricity, but that it be BETTER than electricity. Of the ideas I've seen in this thread so far, none meet this criteria (with the possible exception of positrons and/or the strong nuclear force). 67.169.177.176 (talk) 07:58, 8 December 2011 (UTC)
Soybean protein
editI have a question regarding soybean protein. We know 100 g soybean contains 36.49 g protein. But a popular soy brand in India called Nutrela, manufactured by a BSE and NSE listed company, claims their brand of Soybean contains 54.2 g protein per 100 g. How this can be possible? Or is it Textured vegetable protein? --Foyrutu (talk) 08:53, 7 December 2011 (UTC)
- As far as I can make out, they do not make the claim for soybeans, but for a processed item that looks like a breakfast cereal to me. If you process the food, you can of course vary the proportions of different constituents. They also claim low-fat, so they probably removed the 20% soy oil - that alone would up the protein content to 50%. --Stephan Schulz (talk) 10:02, 7 December 2011 (UTC)
- Thanks, I get it now. --Foyrutu (talk) 11:50, 7 December 2011 (UTC)
- They could have dried the soybeans. In that case, the resulting product contains much less water than the soybeans, so its mass is significantly less, but the protein content doesn't change. That means your figure of protein content per unit mass will increase. – b_jonas 13:32, 7 December 2011 (UTC)
- Update: ah, but Stephan Schulz's solution seems more likely, as soybeans don't contain too much water according to the table you've linked to. – b_jonas 13:33, 7 December 2011 (UTC)
conservation of momentum in inelastic collisions..
editWhy?I mean, if the collision makes a sound, it means that the particles of the masses that collided exerted a force on the air molecules, and by Newton's third law, it means that they exerted a force on the bodies, too, so the momentum is not conserved, since there's external force...--Irrational number (talk) 09:08, 7 December 2011 (UTC)
- Don't forget, momentum is only conserved in a closed system. Plasmic Physics (talk) 09:12, 7 December 2011 (UTC)
- That means you have to include the momentum of the air molecules in your momentum conservation law 157.193.175.207 (talk) 10:47, 7 December 2011 (UTC)
- On principle, you only collide spherical cows in a vacuum. But even in practice, the sound may carry away energy, but little momentum. Sound is a longitudinal wave, it does not involve a permanent linear movement of particles. --Stephan Schulz (talk) 10:06, 7 December 2011 (UTC)
- And the sound propagates in all directions, so any momentum carried by the ways (already negligible anyways) will be cancelled by the sound wave sent in the opposite direction. Dauto (talk) 15:58, 7 December 2011 (UTC)
- But, since the question specifically does ask, momentum is carried by air. The continuity equation for gas flow is constrained by conservation of momentum. If you follow this mathematical exercise through to its logical conclusion, you rederive the gas equations (the Navier–Stokes equations, or one of the variations of those formulas). The Wikipedia article shows an analytic derivation of Navier-Stokes with attention to the conservation of momentum. This physical term contributes to the equations anywhere you see a velocity-flux ( ).
- It is very rare that a practical solution for collision between two solid bodies requires consideration of momentum in the gas. I can think of two places where you do care about this: the analytical solution of the combustion chamber dynamics inside an internal combustion gasoline engine, wherein a chemical reaction causes a gas expansion and then drives a mechanical piston - that's an inelastic collision between expanding gas and the cylinder head; or the analytic solution of combustion chamber dynamics inside a rocket engine, wherein gas momentum is so great that it drives the entire vehicle. Nimur (talk) 17:37, 7 December 2011 (UTC)
- well my point was any reduction in the mechanical energy requires the interaction of the system with it's environment, and thus forces will be exerted on the system in the process, so it's not accurate to say we have conservation of momentum where there isn't conservation of energy, now i know that i'm wrong, because i reached a wrong conclusion, but i don't know WHY(OP).....--95.82.51.215 (talk) 17:26, 7 December 2011 (UTC)
- There are many situations in which the total momentum of a system is conserved (to a very good approximation), even though lots of energy is lost to the surrounding environment. All that is necessary is that the loss of energy occurs as a result of forces that are equal and opposite and act for the same time, or, more generally, forces that have a vector average of zero when integrated over time. See Newton's second law. Dbfirs 19:05, 7 December 2011 (UTC)
- For one thing you can have loss of mechanical energy without any external forces at all. Internal forces might convert Mechanical energy into heat. Another thing is that the momentum of external forces could cancel each other even if all those forces are exerting a net negative work and removing energy. Dauto (talk) 19:39, 7 December 2011 (UTC)
- Conservation of energy and conservation of momentum are different things. The momentum is usually lost to other factors, such as friction, but an object falling onto a surface without any rebound (ie. plasticene) would lose all of its momentum yet feel only half the impulse of an elastic object rebounding to its original height (minus air resistance). ~AH1 (discuss!) 01:13, 8 December 2011 (UTC)
spin is taken as a quantum number
editwhat is the reason to take spin quantum number?what does it physically stand for? — Preceding unsigned comment added by Bidhanism (talk • contribs) 14:18, 7 December 2011 (UTC)
- It stands for the intrinsic angular momentum of the particle. That's analogous to the classic angular momentum of a spinning object - hence the name. Dauto (talk) 15:55, 7 December 2011 (UTC)
- Bit off topic, but you may be interested in Heisenberg uncertainty principle. For some parameters you can't measure both simultaneously. ~AH1 (discuss!) 01:09, 8 December 2011 (UTC)
capilary rise
editwhen a tube of insufficient length is immersed in a liquid,will the liquid overflow? — Preceding unsigned comment added by BENADIK (talk • contribs) 15:54, 7 December 2011 (UTC)
- No, that would violate conservation of energy. Dauto (talk) 16:04, 7 December 2011 (UTC)
- That does happen with superfluids. See the third paragraph of Superfluid#Background. Red Act (talk) 16:27, 7 December 2011 (UTC)
- You need to heat the superfluid to provide the needed energy. Dauto (talk) 16:29, 7 December 2011 (UTC)
- You need to apply heat to get the fountain effect, but my understanding is that a Rollin film will form without needing to apply any energy from an external source. Energy is conserved, because the increase in gravitational potential energy is counterbalanced by the decrease in potential energy associated with the adhesion between the superfluid and the surface. Red Act (talk) 17:12, 7 December 2011 (UTC)
- You need to heat the superfluid to provide the needed energy. Dauto (talk) 16:29, 7 December 2011 (UTC)
- Yes, that's correct. Dauto (talk) 18:40, 7 December 2011 (UTC)
Pulling Teeth
editWhen teeth are pulled, don't at least some alveolar bone get destroyed via microfractures/broken bone?Curb Chain (talk) 18:36, 7 December 2011 (UTC)
- Dentists wouldn't normally pull a tooth which is well rooted. The teeth which are pulled are likely already separated, due to infection, etc. StuRat (talk) 18:24, 8 December 2011 (UTC)
- Yes, they normally wouldn't. Infact, they would exhaust all other remedies before they would pull teeth, because doing so is a last resort where all other remedies have failed. My question is:
- Consider the molar: the alveolar bone is surrounded by concave roots. Does this alveolar bulge get fractured (in some way) when it gets pulled?Curb Chain (talk) 20:34, 8 December 2011 (UTC)
- I would think that wisdom teeth are often pulled while well-rooted. ←Baseball Bugs What's up, Doc? carrots→ 23:06, 8 December 2011 (UTC)
- When I've had teeth out, sometimes small fragments of bone have worked their way out of the gum in the following weeks. --Kurt Shaped Box (talk) 23:15, 8 December 2011 (UTC)
- I had my wisdom teeth out earlier this year at 31 years old and the dentist said not to put it off any longer, given that healing may be more complicated the older I get. He mentioned the very reason: some bone would come out with it, and that would take longer to heal. And, lo and behold, he told me post op that he had to chisel out small bits of bone to get teh wildly crooked wisdom teeth out. Mingmingla (talk) 23:48, 8 December 2011 (UTC)
- When I've had teeth out, sometimes small fragments of bone have worked their way out of the gum in the following weeks. --Kurt Shaped Box (talk) 23:15, 8 December 2011 (UTC)
contact lenses and acid
editWhy is it more damaging/dangerous to get acid in your eyes if you're wearing contact lenses? I've heard this stated before as the contact lenses will melt onto the cornea? 86.7.42.12 (talk) 19:23, 7 December 2011 (UTC)
- Probably because the acid can get trapped under the contact lens.Curb Chain (talk) 19:24, 7 December 2011 (UTC)
- Basicly what Curb Chain said. When you get a contaminant in your eyes, the first thing that happens is that tears are produced which help dilute the contaminant and then your blinking can wipe it off of the surface of the eye. Contacts hold onto and concentrate the contaminant, preventing your tears from diluting it, and blinking doesn't move the contacts. That's why you shouldn't wear contacts when working around certain chemicals (not just acids). --Jayron32 19:31, 7 December 2011 (UTC)
- So could you just remove the contact lens and rinse the eye as you would with an acid-splashed eye that wasn't wearing contact lenses? For some reason I've heard that it becomes impossible to remove the lens, but I'm dubious of this. 86.7.42.12 (talk) 19:39, 7 December 2011 (UTC)
- I am a certified Emergency Medical Responder and I have never heard of this. The contact lens should be removed if you get chemical in your eye. It should be flushed. Who told you this and s/he is probably wrong.Curb Chain (talk) 20:07, 7 December 2011 (UTC)
- Acid-splashed eyes tend to spasm shut, which would make it harder (NOT impossible) to remove the contact lens. Also, chemical burns happen very rapidly (15 seconds or less), so by the time the lens is removed, it's very likely that permanent damage has already occurred. 67.169.177.176 (talk) 08:03, 8 December 2011 (UTC)
- The above IP is correct. I recently had a scare caused by my own stupidity where I forgot to put my eye protection on after a break from my experiment, and ended up getting some sodium oxide in my left eye. I immediately rinsed out my eye and attempted to remove my contact lenses, but I found it quite difficult to keep my eyes open wide enough to do so. Nothing happened to the lenses, but my eyes were so badly irritated I could not keep them open. I got extremely lucky in that I only ended up with a very minor burn which was not on my cornea and a nasty case of chemical conjunctivitis. But you can be damn sure I'm not making THAT mistake again. -RunningOnBrains(talk) 08:20, 8 December 2011 (UTC)
- Even so, given the rapid timescale of the burn, is there a chance that the contact lens actually shielded your cornea from the burn? Wnt (talk) 04:03, 9 December 2011 (UTC)
- Don't try testing this at home
though I secretly pray that you'd be so stupid as to actually try it at home and burn your eyes out with Drano, you green fanatic...67.169.177.176 (talk) 07:05, 9 December 2011 (UTC)- Where did that nasty comment come from? -- User:Dauto 14:59, 9 December 2011
- From a Californian who has escaped the block-hammer so far, but this is going too far and I've asked for admin assistance. ←Baseball Bugs What's up, Doc? carrots→ 15:15, 9 December 2011 (UTC)
- Actually, I have been blocked once before under a different IP, for upholding the truth in an edit war on the article Extermination through labor. And as far as this matter: I want to qualify that I did NOT intend this comment as a threat, and would NOT actually do this to Wnt even if I had the opportunity (but on the other hand, if he did this to himself, either accidentally or deliberately, I likewise would not lift a finger to help him). And BTW I don't give a flying fuck if you block me a second time -- I can get by without Wikipedia just fine, thank you.67.169.177.176 (talk) 00:31, 10 December 2011 (UTC)
- They issued a one-week block for the personal attack. Presumably, 67.170.215.166 (talk · contribs) is the other IP he's talking about. ←Baseball Bugs What's up, Doc? carrots→ 01:46, 10 December 2011 (UTC)
- Just for clarification, the previous argument was at [2]. I have often been quite mystified at the anger of those opposing any complaint about noise pollution; it seems to me far out of line with the reaction to similar issues. I should note that I did not request or know about this block myself, and don't find the comment above particularly disturbing; it is well worth enduring that and more in the hope that, someday, I might understand and counteract this psychological phenomenon. Wnt (talk) 05:30, 11 December 2011 (UTC)
- From a Californian who has escaped the block-hammer so far, but this is going too far and I've asked for admin assistance. ←Baseball Bugs What's up, Doc? carrots→ 15:15, 9 December 2011 (UTC)
- Where did that nasty comment come from? -- User:Dauto 14:59, 9 December 2011
- Don't try testing this at home
- Even so, given the rapid timescale of the burn, is there a chance that the contact lens actually shielded your cornea from the burn? Wnt (talk) 04:03, 9 December 2011 (UTC)
- The above IP is correct. I recently had a scare caused by my own stupidity where I forgot to put my eye protection on after a break from my experiment, and ended up getting some sodium oxide in my left eye. I immediately rinsed out my eye and attempted to remove my contact lenses, but I found it quite difficult to keep my eyes open wide enough to do so. Nothing happened to the lenses, but my eyes were so badly irritated I could not keep them open. I got extremely lucky in that I only ended up with a very minor burn which was not on my cornea and a nasty case of chemical conjunctivitis. But you can be damn sure I'm not making THAT mistake again. -RunningOnBrains(talk) 08:20, 8 December 2011 (UTC)
- Acid-splashed eyes tend to spasm shut, which would make it harder (NOT impossible) to remove the contact lens. Also, chemical burns happen very rapidly (15 seconds or less), so by the time the lens is removed, it's very likely that permanent damage has already occurred. 67.169.177.176 (talk) 08:03, 8 December 2011 (UTC)
- I am a certified Emergency Medical Responder and I have never heard of this. The contact lens should be removed if you get chemical in your eye. It should be flushed. Who told you this and s/he is probably wrong.Curb Chain (talk) 20:07, 7 December 2011 (UTC)
- So could you just remove the contact lens and rinse the eye as you would with an acid-splashed eye that wasn't wearing contact lenses? For some reason I've heard that it becomes impossible to remove the lens, but I'm dubious of this. 86.7.42.12 (talk) 19:39, 7 December 2011 (UTC)
Water collecting on paper towels
editA hopefully simple question. When, you clean up a spill with paper towels, where do the liquid molecules go? It's obvious their atoms don't just fuse together, but are the paper towel molecules spaced out enough that the water molecules can fit inside the spaces of the paper molecules? 64.229.180.189 (talk) 20:29, 7 December 2011 (UTC)
- Pretty much. The water molecules simply fill the spaces in the paper towel, which are substantial. Paper towel fibers are also flexible and can thus expand to hold more water than may be readily apparent from the dry towel. --Jayron32 20:41, 7 December 2011 (UTC)
- Unfortunately, our paper towel article does not address the mechanism beyond stating that they are an "absorbent textile" which "soak up water because they are loosely woven which enables water to travel between them, even against gravity". Note that the water doesn't fit inside the the space between individual paper towel molecules as much as it is drawn inside much larger structures of the paper towel. Capillary action (section: Examples) mentions the wicking action of paper towels. Does anyone here know what the approximate size of the structures involved are, an how much larger they are than individual molecules? Also, in a strict chemical sense, are "super absorbent paper towels" really absorbent, or would that require the inter-molecular action the OP suggested? -- ToE 00:03, 8 December 2011 (UTC)
- Even tightly woven fabric can be quite waterproof so I really don't think there's any "in between molecules" happening there. I think it would have much more, if not all to do with Capillary action as noted above. For illustration steel wool can soak up a considerable amount of water even though the actual steel fibers would obviously not be absorbing any water. Vespine (talk) 00:12, 8 December 2011 (UTC)