1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Heat and Gravity

  1. Jul 18, 2010 #1
    Can gravity absorb heat energy by converting it into gravitational potential energy?

    I always imagine heat is just kinetic energy but more randomised. meaning that if such movement occurs against the force of gravity then, it is converted to gravitational potential energy.
     
  2. jcsd
  3. Jul 18, 2010 #2

    russ_watters

    User Avatar

    Staff: Mentor

    Well, it depends on what exactly the constraints of your question are: a car converts chemical energy to heat energy to kinetic energy....which can then be converted to potential energy if you drive uphill.
     
  4. Jul 18, 2010 #3
    well how about you have pressurised gas in a canister and you then release it into a long capped end pipe, that is vertical. If i released it in from the bottom, would it be cooler than if released from the top. Based on the idea that diffusion is powered by heat energy and when released from the bottom it works against gravity and from the top, gravity aids it.

    Can heat turn directly into gravitational potential energy.
     
  5. Jul 18, 2010 #4

    russ_watters

    User Avatar

    Staff: Mentor

    I suppose a gun firing up would probably also qualify: chemical energy -> heat energy -> kinetic and potential energy.
     
  6. Jul 18, 2010 #5
    So, yes to the above?
     
  7. Jul 19, 2010 #6

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Conversion of kinetic energy of air molecules into gravitational potential energy is the main reason that the atmosphere does not leave the earth. The air molecules do not have sufficient kinetic energy at atmospheric temperatures to escape earth's gravity. It is also a factor causing temperature to decrease with increasing altitude.

    AM
     
  8. Jul 19, 2010 #7
    So, if these molecules that have converted heat energy to gravitational potential energy, condense then fall, gravitational potential energy is converted to kinetic energy?
     
  9. Jul 19, 2010 #8

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Correct.

    AM
     
  10. Jul 22, 2010 #9
    Can anyone link me to something that such a situation does not defy the second law of thermodynamics. It probably has to do with pressure and i would like have a better understanding.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook