Is perpetual motion impossible?

Discussion in 'Chemistry' started by Chatha, Apr 27, 2007.

  1. Chatha big brown was screwed up Registered Senior Member

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    Mr teacher says its impossible to achieve perpetual motion. I think all things in fact move in perpetual motion, just not in the same magnitude, form , or direction. Another question I have is the entropy equation S = Q/T. By this equation, mass contributes to further entropy because is equal to Q. This goes against basic laws of Kinetics, where we know that lighter objects move faster, and as such also contributes to entropy. A fat man for instance can not move around faster than a thin man, even though the fat man has more stored energy. Another interesting thing we covered on entropy was the law
    S*universe = S*system + S*surroundings, he used it to explain why its possible for us to have evolved from lower energy organisms. We are the system in the equation, and our organization is offset by the disorganization of the surrounding.
     
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  3. Positron Agony: Not all pain is gain Registered Senior Member

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    No, it is not impossible, but you need very specific circumstances to obtain it. A Pendelum comes very close on earth and actually acheives it in space. The problem generally lies with gravity but when you are in a zero gravity environment it is absoultley possible. I would reccommend asking the physics folks to, but they tend to lurk around the chemistry area as well.
     
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  5. draqon Banned Banned

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    nowhere is gravity 0 in this world. Even far away into nothingness with billion of light years separating object from anything else...it will still experience gravity.

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    ...And thus Perpetual Motion is impossible.
     
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  7. Gently Passing Registered Senior Member

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    In theoretically empty space with a single particle moving in some direction, sure it's possible. The inertia of the particle would dictate that it would keep moving with the vector v forever.

    But in our universe any particle is likely to interact with some other particle at some point in time (gravitational forces count), therefore the hypothetically empty universe is rejected and perpetual motion is impossible for us.

    Now if we develop some technology with which to create empty dimensions or something, manipulating the nature of spacetime, perhaps we could get this to work (pure science fiction...but it's a thought experiment so work with me...)

    BUT if we observe the particle we must interact with it in some way to verify the predicted results - we must remove energy from the system that we can measure.

    I suppose we could let it fly along in this empty dimension for a given amount of time and then allow it to lose momentum by interacting with our instruments and if the energy observed is equivalent to the predicted energy then I guess we could prove it.

    But we'd have to first verify that a superstring-type model is at work (in which multiple unseen dimensions interact in some complex way to give us space and time as we know them) and then we'd have to engineer some kind of device that would be capable of manipulating this in some way to achieve the desired effect...

    It's quite a problem from an engineering standpoint, though I suspect it's not far beyond the level of an upper-level Physics major to prove (or disprove) using relatively simple mathematics.
     
  8. James R Just this guy, you know? Staff Member

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    Chatha:

    In thermodynamics, "perpetual motion" has a specific meaning. It says that you can have a process which entirely converts heat to useful work, without any other effects on the environment. This kind of perpetual motion is what is prohibited by the second law of thermodynamics. It is what prevents so-called perpetual motion machines from being possible.

    Perpetual motion is NOT motion according to Newton's first law, for example.

    No. Q is heat, not mass. And, before you start, heat does not include rest mass energy.

    No idea what you mean by this. Give any object enough energy and you can make it move at any speed up to the speed of light.

    Yes. In any process (e.g. evolution), a system can become less disorganised, but only at the expense of the general environment becoming more disorganised.
     
  9. Gently Passing Registered Senior Member

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    Okay, it's this simple: perpetual motion is REAL and exists all around us all the time. In fact we know it quite well as the conservation of energy...

    Take one particle in an empty universe, give it a mass and a velocity.

    It should keep on moving in that direction at that velocity forever, right?

    Perpetual motion.

    Now put trillions upon trillions of particles in a universe. Give one of them a mass and a velocity. Assuming it interacts with another particle, you now have two particles moving in two different directions and some radiation that will now also interact with another particle and so on.

    The universe is in perpetual motion all the time, it's just that perpetual motion is impossible for a given system because it will radiate heat.

    What do you call cosmic background radiation?

    Something is moving somewhere.
     
  10. TruthSeeker Fancy Virtual Reality Monkey Valued Senior Member

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    Is perpetual motion impossible?
    I suppose perpetual motion means that it never ends...?
    Well, for something to move, it must use up energy, right? So if you can create something that regenerates energy when energy is used, then I suppose a perpetual motion thingy is possible...
     
  11. Positron Agony: Not all pain is gain Registered Senior Member

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    Aye, but I generally speak only in theoretics. While I realize that gravity has an effect no matter where you are, for all intensive purposes that pendulum will keep ticking longer than you or earth can live thats for sure.
     
  12. MetaKron Registered Senior Member

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    Do you have a scholarly reference that says this?
     
  13. Read-Only Valued Senior Member

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  14. James R Just this guy, you know? Staff Member

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    Did you bother reading the post immediately above the one from which this quote is taken?


    Pick up any introductory physics texts which discusses the second law of thermodynamics. Any undergraduate first-year text will do.
     
  15. MetaKron Registered Senior Member

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    BIG cop-out.
     
  16. Read-Only Valued Senior Member

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    Right! Someone suggests that you actually LEARN something for a change and you call it a cop-out. Figures.
     
  17. Chatha big brown was screwed up Registered Senior Member

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    A very simple way to understand the process is to know that every system in the universe prefers a state of lowest energy, which also is a state of increasing entropy. Because everything tends to rest, perpectual motion is therefore practicaly impossible.
     
  18. Blutonium Boy Registered Member

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    I think tabletop perpetual motion or overunity would be impossible to achieve, however I do encourage that people try and build exotic stuff in their garage, as they might accidentally stumble onto interesting phenomena that prove usefull for other scientifical or technological/industrial purposes.

    Also I believe its entirely possible that somebody one day builds a device that at first sight indeed qualifies as overunity and indeed in OUR dimension creates more energy output than was given input, but that upon further inspection it will show that this energy was siphoned off from a dimension with a higher energy state, so their would be still a zero overall sum and no thermodynamic laws would be violated, if we consider the overall entropic state of all dimensions involved, but we would be able to get to benefit, so yes keep building that stuff...
     
  19. Kendall ......................... ..... Registered Senior Member

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    I think It is possible, not even difficult but you would need gravity for an opposite force, around 100lb magnets and gravity. Like a circus wheel where rods with large cylindrical magnets on each end that would have play to move some distance in each direction with the rods going through the core of the wheel and one magnet that is firmly attached to the bottom of the housing that the wheel is attached to as the magnets attached to the wheel passes the magnet attached to the housing they would be pushed upward maybe with the help of a magnet at the opposite side of the wheel and there should be a excess weight on the downward spin from the distance between the magnet and core(for lack of the proper word) of the wheel. There might need to be a mechanism to hold the magnets out without the magnetic force in order to obtain perpetual motion.
     
  20. Oli Heute der Enteteich... Registered Senior Member

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    Demonstrate that these "other dimensions" exist and that we can tap energy from them...

    Kendall, bearing in mind that gravity will be acting equally on both sides of the wheel/ rods how would this give any motion, let alone perpetual?
     
  21. Kendall ......................... ..... Registered Senior Member

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    One side of the wheel would have the magnets at a greater distance from the center of the wheel creating much more weight.
     
  22. Oli Heute der Enteteich... Registered Senior Member

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    But a magnetic field will stabilise the weights at a given distance from the magnet... they won't keep pushing all the way round. Or am I totally misunderstanding your description?
     
  23. Kendall ......................... ..... Registered Senior Member

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    It might I am not sure, that is why I added that a mechanism to keep the magnets held out during the downward half of the spin might be needed, I do not think that it would be needed with the proper design but would maybe increase the torque and/or speed.
     

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