Perpetual motion machines: possible?

Possible to build them?

  1. Yes, we should be able to build them

    7 vote(s)
  2. No, it is against the laws of energy conservation

    25 vote(s)
  3. It may be technically possible, but only in the distant future

    5 vote(s)
  1. By this I mean machines that put more energy out than is put in.

    Is it possible?
  2. jcsd
  3. Unequivocally impossible.
  4. enigma

    enigma 1,817
    Staff Emeritus
    Science Advisor
    Gold Member


    not possible in this universe.
  5. Perpetual motion machine?

    Perpetual motion? No problem!

    Perpetual motion machine? No chance!
  6. Even if we someday produce a machine that appears to do more work than input energy would allow, it is just that we do not fully understand the ultimate source of the energy. Such as some of the designs involving magnetism.
  7. "Any sufficiently advanced technology is indistinguishable from magic."

    -- Arthur C. Clarke
  8. Clausius2

    Clausius2 1,479
    Science Advisor
    Gold Member

    If a perpetual machine would be possible, there would be something similar in the Nature. But it is impossible because Nature and Universe are not perpetual, they had a beginning.

    The only we need to built one is a frictionless material, so let's search one!. (but while you are searching I am going to visit my fridge.)
  9. Physics; Pertpetual motion is impossible.
    Cosmology;The universe is in constant motion.

    Cancel out common denominators...

    The universe is impossible !

  10. As far as the universe, it is not a question of perpetual motion, but the energy availability to do useful work. The universe is constantly expending its useful energy (primarily through nuclear fusion) and one day no further fusion will be possible once too of the Hydrogen has been converted to Iron. Once this occurs, everything will thermalize such that there is no difference in temperature and no further work can be extracted. Perhaps the protons may even begin to decay away according to some theories. The spiral will continue downward until you can get no usable work. The universe will die.

    The universe is completely consistent with physics.
  11. Yes, there is a difference between "perpetual" and "constant". Constant motion doesn't neccesarily indicate perpetual motion.
  12. Aren't nature and the universe the same thing?
    If they had a beginning, then wouldn't they have "began" in a point in time? If so, then for it to begin, wouldn't its beginning be a "beginning" relative to other points in time?

    Superconductors have been "made" you know.
    now I think I'll go visit my fridge.

    BTW, I have a question. Is it not true that if you apply a force on a ball in space, it will continue in that direction until acted upon by another force? Is it impossible for the ball to continue in perpetual motion [while in space] because eventually, it will be influenced by some other force?
  13. Well then it is still true what you said... it continued in the direction until it was acted upon by another force. If there is nothing to slow something down, why should it. It would imply that it is losing energy by solely moving. On earth energy is lost through friction and heat but in space in a vacume until it feels some sort of force it will have no reason to change direction.
  14. cronxeh

    cronxeh 1,232
    Gold Member

    perpetual motion is impossible. from laws of thermodynamics:

    energy can neither be created nor destroyed
    bodies in motion tend to stay in motion unless an external force acts upon it

    the universe is in constant motion from the big bang. will it stop doing that and go back towards singularity? probable. sort of like a rubber band. but even this process can not be described as perpetual in itself. something drives the expansion (explosion for example)

    another thing about the machines.. if the friction isnt a problem.. and even if gravity isnt one.. certainly you'll never get more energy than what you put into that machine

    you need to tap a source of energy to get it back.. please dont waste time on perpetual motion machines and start researching cure for cancer, cold fusion, run SETI@Home, do something but waste your and ultimate worse, others time
  15. megashawn

    megashawn 506
    Science Advisor

    hehe, you say not to research pm, but then suggest to research cold fusion. LOL

    Perpetual motion is a noble search. With such power, noone would have to work, for we'd have enough energy to do all sortsa cool stuf. But it isn't gonna happen. This very idea is what original brought me to this forum. I've learned and changed alot since I first came here (so has this forum now that I think about it).

    I was so convinced I had come up with PM, I had come up with a method I still haven't seen anyone trying to use. It functioned, it moved, it melted my battery cause I was trying to put energy back in it while pulling energy from it. And yes, I wasted alot of time toying with it. But I learned some important things.

    Picture the old school pm machines. The flywheels with the counter weights that slide back and forth, creating a downward force which would spin it back up again.

    In a 0 gravity, frictionless enviroment such a thing would spin for quite sometime. Keep in mind the definition of perpetual motion: A machine which, once set in motion, will stay in motion until parts wear out or it is stopped.

    In that regards, I'd say the universe could very well be considered perpetual motion. I don't know about the machine part, for that implies a creator, to many issues to touch there.

    Anyhow, back to the ole school wheel. Lets say you get it spinning, say, 10,000 rpm. You put a pulley on it that turns a belt, which turns a generator. For each time the wheel turns, the generator turns twice. By turning a generator, and say, powering a house, you remove rotational energy from the wheel, convert it into electrical energy, and burn it in your television.

    Eventually, the wheel will stop spinning, as each watt you draw from the energy exerts an opposite force on the wheel. Now, while it isn't perpetual, here is the trick. On the opposite side of the wheel which contains the generator puller, you setup an even larger puller, twice the size of the spinning wheel. This pulley is hooked up to an electric motor which is driven by a nucleur/thermoelectric generator.

    The purpose of the wheel, instead of producing energy, becomes a sort of mechanical battery. In that it converts electrical energy into rotational energy, which can then later be extracted back out and put into use. Would you like to see something like this in action? Rip the engine out of your car. See the flywheel? Same concept. Check out a pottery wheels, they are peddle powered, spin up to speed, spin for a while, friction takes its toll and you must pump it again.

    That is one of the major problems. We don't have a good electricity tank. We can't put 5 gallons of electrons in a plasitc tank and carry it out in the middle of the woods with us. It isn't so much that we don't have ways to generate electricity, but moreso we don't have ways to stockpile it, and any excess energy that is produced is wasted. That, is where your time would best spent, trying to figure out how to store electricity better.
  16. Good response Megashawn. I like your thought on the storage of energy being the real challange.
  17. Perpetua Motion Machines

    Law of Origin states, "A body set in motion, from a point of origin, will come to rest", meaning, anything that is set into motion from a ground state, will eventually come to a grinding halt, such things as planes, trains, automoblies, solar panel generators, windmill generators, nuclear power generators, etc, and because this things are finite, they do not voilate any laws of thermodynamics.

    Perpetual Motion Machines have a ground state making them finite not infinite.
    Last edited: Aug 1, 2004
  18. I agree with that soo much.
  19. Locrian

    Locrian 1,800
    Gold Member


    Any sufficiently advanced science is 100% distinguishable from magic.

    Edited twice, I seem to have no typing skills today.
  20. russ_watters

    Staff: Mentor

    Law of Origin? Never heard of it and it ain't how our universe works.
  21. Perpetual Motion

    [edit] Sorry, but your gibberish is not physics and is not allowed in my forum. In the engineering forum, we necessarily only deal with real physics (caveat - a discussion on why perpetual motion doesn't work can be useful). Keep it in the TD forum. And keep the spam off the entire board.
    Last edited by a moderator: Jul 20, 2004
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