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John Cuthber

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Everything posted by John Cuthber

  1. Careful addition of liquid oxygen to the fuel in a car could easily result in the car reaching the speed of sound. Unfortunately this will be in a multitude of directions simultaneously. Also, the driver wouldn't survive to claim any glory, in fact it might be difficult for his next of kin to find any bits of the driver big enough to claim for burial.
  2. IIRC the lifetime risk from smoking is about 50% ie half of smokers die from something related to it. Of course the lifetime risk from living is 100% - everyone dies. There's also the fact that even non-smokers die from things, like lung cancer, that are usually thought of as smoking related. Still, what other product can you think of which, when used in accordance with the manufacturers instructions, has a 50:50 chance of killing you? The fact that you don't smoke much now is pretty near irelevant. Nobody ever started off as an 80-a-day smoker. Like many people here, I think you should
  3. SkepticLance, I think that's a fine method for determining whether or not something is self-aware, but it has a problem. All blind animals fail. Now, I'm not a great admirer of cats- as far as I'm concerened they just mess up my garden. I pointed out to some cat lover that cats are dumb- they don't even react to their reflection in a mirror. He pointed out that it could be because cats are smart- they know that the image doesn't smell like a cat so they know it's not real. Good luck applying the mirror test to an animal that generally lives in the dark and percieves its environment by echo
  4. This table gives density vs mole fraction for sulphuric and nitric acids. http://www.kayelaby.npl.co.uk/chemistry/3_6/3_6_3.html
  5. Oh, BTW, I think the same problems (eddy currents and demagnetisation) will happen with magnetic bearings. They still work so the idea is perfectly plausible, I'm just not sure how many applications you will find for it. The "gogging" effect ie the variation in torque will be horrible if you only use 4 teeth but I can't see a problem with using lots (OK that's like a conventional gear) but it's still non contact, so no friction and no wear. It would be interesting to see what the people who do "nano machines" think of this- they have real problems with friction.
  6. I don't see Blair as the type to read much so I guess it was down to Rushdie's support from the literary world (rightly or wrongly). (and I think most of the queen's grandchildren are a bit old for Harry potter but that assumes they havew normal reading abillity.)
  7. Why are ethics and philosophy not open to scientific explanation? In the limit they both happen in human brains; they are the results of a very complicated set of chemical reactions. As far as I know religion doesn't really answer anything anyway- saying "because God said so" isn't an answer unless you explain God.
  8. You could do it with very clean glass. Paint the image on with silicone oil then spray a fine mist of water onto it. The mist will stay as fine drops where the oil is but will spread out to a thin layer where the glass is clean. That way you can really use water in the spray. Otherwise you are basicly looking at the world of invisible inks and developers. I'm sure google will help you with that.
  9. For this to work you need to keep track of which atoms are part of you and which are not. Breathing mixes them up. The door is a much simpler idea.
  10. Since nobody has specified the pressure in the helium ballon it is perfectly possible to have a helium balloon in a vacuum. You just need to be sure not to put much helium in it. BTW, I don't play baseball so I'm no expert but re. "at ground level look more like a baseball in the bottom of a condom". Wouldn't that be the wrong way up?
  11. Roughly how common is that?
  12. There are real losses due to eddy currents. On the other hand the idea that the magnets"wear out" isn't a real problem. The worst position for a magnet to be in from the point of view of demagnetising force is next to another magnet N to N and S to S. Any combination of gears will sometimes be less strongly demagnetising than this. Think about an ordinary bar magnet- it is 2 magnets stuck together head to head and tail to tail. If you cut it carefully down the middle you get 2 magnets. Since ordinary magnets are stable for years there is evidence that these gears should work well. On the
  13. Joy, Do you understand that there is a difference between "poodles are dogs" and "dogs are poodles"? Similarly, there is a difference between "liquids that acts like a solid under pressure are non newtonian" and "non newtonian liquids acts like a solid under pressure ". Since the second of these is what you said, but the first of them is true I still think you were wrong.
  14. "Are not arrogant and inconsiderate bicyclists equally as annoying as their counterparts in cars?" No, because they don't kill other people.
  15. I agree that you should "think before you drink"; it's darned hard to think properly afterwards. Anyway, I used to brew my own and the best advice I can give is keep everything clean. (Also don't prime bottles with too much sugar)
  16. Breathing might be an interesting problem too.
  17. Well, you may say "That's assuming the building doesn't have a decent ventilation system... but ours does." But there seems to be some question of the adequacy of the ventillation. "After about an hour and a half, they let us back into the building, but they turned up the vacuum system in the building, so get the fumes out and to cycle the air, I guess. The problem, is that this changed the pressure significantly in our P2 lab (for dealing with hazardous pathogens), which set of an alarm. (sigh)." Anyway, no reasonable ventillation system can keep the methanol concentration above a large
  18. If you need to ask that sort of question please don't try working with phosphorus (red or white). The reactions are rather complex but they can be summed up as the glycerine get's oxidised by the permanganate. This reaction generates heat and the hotter the mixture gets the faster it reacts. The temperature rises rapidly until the material catches fire.
  19. Yeah, It's just methanol. Roughly as flammable as gasoline. Burns with a near invisible flame so it's possible to walk into a methanol fire before you see it. It's got an idlh value of about 8 g /metre cubed so 4 liters ie 3.2Kg is enough to make 400 cubic metres of air unbreathable. Hey, why tell anyone to get out of the building? It is noted for its ability to be absorbed through the skin but that's no reason for the delivery bloke to remove any contaminated clothing. It sends you blind at doses less than it takes to kill you but if it's a choice between that or flashing next week's w
  20. Since AgSCN is practically insoluble you can't really do a titration with it. You can use it as part of an indicator system (in the presence of Fe). Titrating with HCl then trying to measure Cl would be ill advised- it's much easier not to add lots of the stuff you are trying to measure. There's nothing to stop you doing the titration with HNO3 to as exact an end point as you can get for the determination of the base then adding excess acid and titrating with AgNO3 to measure the chloride, again to as good an end point as you can get. Warming the solution isn't going to help a lot e
  21. Since many elements show multiple oxidation states the table is ambiguous. If it's meant to me highest oxidation states then copper is wrong; if it's meant to be most common then iron is wrong. If the asignment is arbitrary then it's all wrong. It also fails to convey any information about the underlying reason for the periodic nature. It springs from the arangement of the electrons in what for simplicity's sake are usually called shells.
  22. "Believing in creationism is kind of like one scientest believing in a certain scientific threory and another one disagreeing with the theory. " Bollocks! In the end the evidence of further experiments should get the 2 scientists to agreee. That's the whole point of science. The creationists will (and do) continue to believe in their "faith" even after it has ben shown to be, at best, unreliable. Believing in fairy tales is not, directly, a bad thing. But if it leads to killing your neighbour because he eats boiled eggs blunt end first then it's very clearly a bad thing. If we stopped to
  23. I know that wiki is not always reliable but, in this case, it is correct. Why bother to raise the matter of wiki's editabillity? it doesn't make any difference to the error you made in the first place.
  24. I don't think anyone has synthesised hexaphenyl ethane yet; there are plenty of similar examples where steric considerations make the molecule impossible. Still the question is a bit odd, I think that several hundred million different compounds have been synthesised. Which ones do you want big ones, smelly ones, left handed ones?
  25. OK, thanks to the incompleteness theorem there are at least some things for which there is no answer. There are quite a lot of things for which, at least in principle, science can give the answer. Is there anything that can give an answer to (at least some) questions that fall outside the first 2 groups?
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