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How is energy transferred?

  1. Apr 13, 2014 #1
    I understand that convection, conduction, and radiation are the modes of transferring energy, but - molecularly - how does this work? Is it transferred from one atom to another? If so, why do physicists say that light energy is made of photons - particles? Referring to quantum mechanics, is it not true that there are no real such things as particles? If I was to hypothesize with the tool of parsimony, then I would say that there are many dimensions, and that the space itself can vibrate, its vibrations within itself vary in frequency and these variations make up everything...Anything wrong with that? Please prove me wrong and explain! I'm going to end this thread before I add another topic...
  2. jcsd
  3. Apr 13, 2014 #2


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    Conduction: the molecules on the hot body are bouncing around more quickly than the molecules in the cold body. Bring them together, and the fast-moving molecules will hit the slow-moving ones, speeding them up while the fast-movers slow down.

    Convection: just like conduction, except that it's the molecules of air around the hot body that receive the energy from the fast-moving molecules. Then the air rises and its now-faster-moving molecules heat something else up.

    Radiation: light energy strikes the molecules of an object, causing them to bounce around more quickly. You could think of that as bombarding the object with photons.

    No, not true.

    You're getting ahead of yourself here... Don't go hypothesizing new answers to questions until you know which questions already have answers.
  4. Apr 14, 2014 #3


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    That notice should be nailed at the top of every thread!
    Last edited by a moderator: Apr 14, 2014
  5. Apr 14, 2014 #4
    Just to precise a bit Nugatory's answer:
    Actually, only the part where "air rises" is convection. The body-to-air and air-to-air parts are still conduction. Convection appears whenever energy moves with the object (e.g. hot liquid moving up due to pressure difference... and that's the extend of my knowledge for natural cases of convection)

    Another part of radiation is the light (mostly infrared at usual temperatures) emitted by an object, which uses up some fraction of the molecules' energy. So any warm object without conduction or incoming radiation will eventually cool down.
  6. Apr 14, 2014 #5
    Thank you everyone!
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