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!

General Energy ? - prob easy to answer

  1. Oct 16, 2009 #1
    Hello -

    I was hoping - without getting too technical (please keep everything as simple as possible! =) ) if it was possible for energy(electricity, whatever you wish to call it) to be transferred from one object or body to another (the same exact energy).

    On a basic level I know that energy can be transferred, etc (Newton's Laws, etc) but I guess I am looking more at the idea of being able to extract energy from an object and put it into another object (almost like how you can pick up water from a tube with a syringe and put it into something else).

    Also, is it possible to trap energy waves as they randomly move around (so if the ball was rolling down a hill could you literally trap the energy it created if it were to suddenly stop). Or is this just done by grounding??

    I apologize if I should completely dumb, but I just thought I would ask the professionals!

    thank you!
    Julia =)
  2. jcsd
  3. Oct 16, 2009 #2


    User Avatar
    Science Advisor

    You should try to be more specific as to what you have in mind. Energy transfers take place all the time. For example making toast - heat is transferred from the toaster to the bread.
  4. Oct 16, 2009 #3
    In the real world energy does not come as a quantity that can be extracted in the way you suggest, but is always in a particular physical form such as heat, electric potential chemical potential, or lots of other forms.
    The way the term is used, you'd easily think otherwise... but 'energy' is an abstract term.
    So sorry, but no.
  5. Oct 16, 2009 #4
    You really have to be specific about what form the energy is in. However thermodynamics will tell you that it takes energy to move energy around. This energy 'loss' is what entropy is all about.

    The idea is sound though, as long as you don't mind loosing some energy to entropy. In fact, its the basic principle of the reverse cycle air-conditioner. Energy is used to pump a gas around a close cycle. The gas is expanded and cools, drawing in energy from its surroundings and then compressed elsewhere, releasing that energy. All you have to do is supply enough energy to keep the gas moving.

    So to do what you're suggesting, you need to have a method which works for whatever type of energy you're working with.
  6. Oct 17, 2009 #5
    It has nothing to do with "waves", but you could do that thing in parentheses. Suppose a ball rolls downhill and hits into a spring, causing the spring to be compressed. Let the ball come to a stop against the spring. Quickly engage a mechanical latch to hold the spring in the compressed condition so that it doesn't bounce back. What used to be the kinetic energy of the ball is now elastic potential energy stored in the compressed spring. At the atomic level, that elastic potential energy is really the electrical potential energy of deformed atomic bonds. There will be some energy loss due to friction, which means some energy has been dissipated as heat.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook