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Everything posted by 314159

  1. I'd classify myself as a bright. A member of a growing group of those who share a naturalistic worldview. Specifically, I'd describe myself as atheist within that group. http://www.the-brights.net/
  2. Wow, that's practically on my doorstep! Are these conferences typically open to the general public? Would it be possible for someone not associated with a university to attend the talks?
  3. Ah, now I feel stupid. Of course the uncertainty principle would mean that particles known to have zero velocity would have a competely unknown location...
  4. 314159

    New motor

    You've not explained what it is. So far it sounds like the type of 'Free energy' device of the type that's been touted for hundreds of years, have never worked, and they often use the 'non-disclosure' tack, supposing that people would steal their idea if it ever got out. If it's real, patent it. I'm not sure what you expect us to say, when you tell us nothing about where your 'free energy' is coming from.
  5. Seeing as maxwell's demon is just an idealised construct in the first place, I think we can assume his paddle doesn't radiate; it's a perfect reflector that emits nothing. He's not physically possible anyway. It's an interesting question, why we can't reach zero K, and the reason I didn't answer earlier is that I don't really understand the reasons we can't. For example, if quantum fluctuations cause random changes in heat energy, surely at some point, in a cold environment, that random change in energy would change the temperature to zero?
  6. Science consists of falsifyable statments. A 'fact' in science is different to a 'fact' in colloquial usage. In common usage 'fact' means absolutely certain, like a mathematical or logical truth, whereas in science someone would be more likely to make the statement 'we can take it to be a fact that...' implying that that particular falsifyable statement has been repeatedly upheld, and is very likely to be true. I think it's also worth noting that differing branches of science tend to have different standards before they would call something fact. I would say something may be considered a fact in biology even if supported far less strongly than a fact in physics.
  7. I'd read your post previously, but I'm still left a litle confused. So you create entangled pairs of photons by passing the light through a non-linear crystal, but how does that actually create an entangled pair? I'm still left none the wiser on points 2/ and 3/, as to how the observations are carried out, and how they prevent any collapse of the states enroute.
  8. I realise this a is little bit of a basic question, but how does quantum cryptography from entanglement *work*? I mean, I know the general idea. Sharing a key without someone observing it, the two quanta to be observed having opposite but undetermined states, but what I mean is, in practice, how are the various steps carried out? Breaking it down: 1/ How does Alice actually go about creating her two entangled particles? 2/ How does she send one of them without them being observed? 3/ When sent (and this is the part I just don't get) what do she and bob actually do *exactly* to transmit the info? What would you measure in a real system, and what info would she send to bob on a classical channel?
  9. It may help to draw an analogy from he electric field with the magnetic field. Imagine a tube with a load of cylindrical magnets inside, each aligned the same way, so each magnet pushes the ones next to it. if you push one magnet in one end of the tube, even if you push it slowly, a magnet will come out of the other side almost instantly. There was a class demonstration with a queue of students in a line, and you pushed the one at the back, and the one at the front moved almost immediately as every person in the queue was pushed against the person in front. The deciding factor is how quickly each part responds to the part behind it, and the electrons respond very quickly, even if they don't individually move very quickly.
  10. Depends on the reactants, I would suspect. There's a handy wikipedia page on the topic. http://en.wikipedia.org/wiki/Organic_oxidation
  11. Quite right. They would both feel the same acceleration except for the effect of air resistance. The balloons both have to push past the air. The balloons experience a force due to gravity. The heavier balloon feels a greater force as it has more mass, so it feels the effect of gravity more strongly, but it is more massive, and so requires a greater force to accelerate it the same as the lighter balloon. These balance out if you have no air resistance, but air resistance depends on the shape of the object (and its velocity), so both balloons are slowed down by a force. The actual force due to gravity on the heavier object is greater, so the air resistance force has less effect proportionally. The lighter balloon may have almost all of the force negated by the air resistance. Take an example. One balloon (Balloon A) has air in and a mass of 10 grams. The other (balloon B) has water and a mass of 1 kilo. The force due to gravity on A is mg, which is 0.098 Newtons of force. The force on B is 9.8 Newtons. That force on A will accelerate it at 0.098/0.01 = 9.8 m/s/s That force on B will accelerate it at 9.8/1 = 9.8 m/s/s So they'd fall at the same rate. Now introduce air resistance of, say, 0.09 newtons, the same for both balloons, as they are the same shape. The force on A is now 0.008 Newtons, accelerating it at 0.8 m/s/s The force on B is now 9.701 Newtons, accelerating it at 9.701 m/s/s You'll see the heavier balloon fall faster, as the air resistance is a smaller fraction of the force acting on it.
  12. You asked about whether someone could be frozen and then warmed up enough to live, which is the idea of cryogenics. The idea is that you cool someone enough that any rot or decay ceases, so you don't need to get right down to absolute zero, just 'pretty cold'. The trouble, at present, is that if you try that, all the water in your cells turns to ice, and ice takes up more space than water, so your cells burst as you get frozen. All the people in cryogenic chambers around the world are massively damaged on a cellular level, and you'd have to do quite a repir job to put them back together. It may be possible in the future to carry out reanimation from a frozen body. There's a frog (or it may be a toad, I forget) that can be fully frozen in winter, and come back to life when it thaws. It does this as it has a high sugar content in its cells which stops the water in them freezing and killing it when it's in its frozen state. In answer to pt 2, as was said, this energy is already there in other forms. matter and energy are essentially the same thing, and energy can be stored in more ways than just a photon. For example, energy may be lost by an electron in an atom, causing a photon to be emitted. Energy is conserved, as it's changed from one form to another. moleculescolliding don't destroy one another, but even if you had a particle collide with its anti-particle, the photon energy coming out would just be the energy that was earlier present in the form of mass, seeing as energy and mass are basically the same thing.
  13. I had the same problem looking after a friend's pet. They can be tough to shift. I used an awful lot of expensive flea spray, but to sort it out you've got to get rid of the ones on the dog first, either at the vet or with flea shampoo, then you can get rid of the ones on bedding by washing at a high temperature (100 degrees C if possible), and hoover any carpets repeatedly. If you can't afford sprays or repellents, you'll just have to keep the place scrupulously clean until they're gone. You may well have to put up with bites to the ankle until the dog moves out.
  14. Quite right. Of course photons have momentum, which is why ideas such as 'solar sails' were suggested, where the momentum of a photon is harnessed. The equations are exactly as you describe. hyperphysics page describing momentum of photons
  15. In an ideal world, all that matters is your ability to do your job, but in reality people elect politicians based heavily on their personal lives and their perception of them. Probably the reason for this is that people consider it more important that the person they elect share their ideology, or conform to their ideal of a 'good person', and will elect someone like that even if they are less competant. People like to feel that their representatives represent them, in the sense of being indicative of who they are.
  16. Yes, I remember I famous (and possibly apocryhal?) story of someone who had a power line built over his property, so he built a secondary coil and produced useable power from it. He was effectively stealing the power, as that produces an equivalent excess load on the system. Similarly, a radio produces a greater drain on a radio transmitter, but only by an incredibly small amount. In reality it won't be easily measurable. So practically it won't be measurable, although theoretically it would. It's an interesting question how correctly tuning the radio affects the original transmitter. I'll have to think about that one...
  17. 314159


    Wikipedia covers much of it. There is a nice page here about electrostatics experiments with a regular pieoelectric lighter. If you search for 'Rochelle salt' you should also find interesting instructions on how to make your own piezoelectric crystals. I find the best (and by that I mean most enjoyable) way to learn about these things is first hand. If you're in the mood for somethign a little stronger, and a lot pricier, Amazon has a wide selection: http://www.amazon.co.uk/exec/obidos/ASIN/0387235736/qid=1147475507/sr=1-3/ref=sr_1_0_3/026-0359138-2625269
  18. Well, in short, it probably wouldn't light up, unless, possibly, the field was absolutely vast. Normally that experiment is electric fields, such as waving a flourescent tube near a Van der Graaff. There the electric field provides the energy. If you managed to get any effect with waving a flourescent tube, it would be equivalent to waving a tube next to a strong permanent magnet. I've just double checked by having a go with a flourescent tube and my trusty neodymium magnets, to no effect. But if there were a case where you did, with a far stronger field, it would have to be down to the changing magnetic field, and so the energy would come from you waving the tube. With no field it would be easier to move it.
  19. Amateur rocketry projects can and do happen. If you were capable of launching an object at any sort of reasonable cost, and with any sort of accuracy, I'd surmise that you could affiliate yourself with a proper space program. In the UK, for example, there have been proper attempts at launching things into space (starchaser UK, for example) which have significant difficulties. You'd still be looking at enormous costs, but a private company or individual should definitely be capable of an attempt.
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