Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Perpetual Motion Machine?

  1. Jul 31, 2007 #1
    I've heard a perpetual motion machine would be impossible, but then that some people out there believe it is. I was wondering if anyone out there has any thoughts on it..
  2. jcsd
  3. Jul 31, 2007 #2
    Its papers done by high school flunkiees.
  4. Jul 31, 2007 #3

    Claude Bile

    User Avatar
    Science Advisor

    It is impossible. You can take that as holy writ.

  5. Jul 31, 2007 #4


    User Avatar
    Gold Member

    By the usual definition of 'perpetual motion', no one with an ounce of brains believes in them. It is possible to have something that moves forever once started, such as a rock spinning in outer space or electric current in a superconducting loop. The point is that no work can be extracted from it without killing it.
  6. Jul 31, 2007 #5


    User Avatar
    Gold Member

    PMM thread: alive 55 minutes and counting!
  7. Jul 31, 2007 #6


    User Avatar
    Homework Helper

    In this forum we obey the laws of thermodynamics!
  8. Jul 31, 2007 #7


    User Avatar
    Gold Member

  9. Jul 31, 2007 #8


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member


  10. Jul 31, 2007 #9


    User Avatar
    Science Advisor

    The key here is the term "perpetual motion machine"; the word "machine" makes it a device that helps one do work. As Danger mentioned, there are events that can give the appearence of perpetual motion, but they can't be called machines, 'cause we can't get any work out of 'em.
    I don't know if you wanted details as to why such a device can't exist, or if you're just taking a little opinion pol.
  11. Jul 31, 2007 #10


    User Avatar

    Staff: Mentor

    Sorry. We were busy.... thread locked.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Perpetual Motion Machine?
  1. Perpetual motion machine (Replies: 29)