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Radiation Fundamentals

  1. Aug 20, 2009 #1
    Hello Everyone,

    Recently, I was trying to explain the fundamentals of thermal radiation to a non-engineer and I discovered that I myself have a poor understanding of it. I understand that "thermal radiation is continuously emitted by all matter whose temperature is above absolute temperature." However, I do not understand who or what is causing these electromagnetic waves to be emitted. According to my textbook [HEAT TRANSFER: A Practical Approach, 2nd ed.], "accelerated charges or changing electric currents give rises to electric and magnetic fields. These rapidly moving fields are called electromagnetic waves or electromagnetic radiation, and they represent the energy emitted by matter as a result of the changes in the electronic configurations of atoms or molecules." In layman's terms, what does this really mean? When atoms heat up, they bounce around faster and faster and produce more and more electromagnetic waves? Why does bouncing around create electromagnetic waves anyway?

    I suppose that I was too busy trying to solve partial differential equations to think of these kinds of questions in college. There was no time to think or ponder. This seems to be the trend as I try to go back and relearn subjects. I gave all the right answers on the tests, but I think I missed some of the more important fundamentals. Those were not on the tests.

    Thank you all in advance!
  2. jcsd
  3. Aug 21, 2009 #2
    I'm only specutaling here, since this is not in my field of expertise.

    The heat radiation emitted from objects is correlative to the speed and intensity of its movement, this makes the object exert more intense and more energetic waves of radiation. This correlation can also be put together through friction, like when two particles collide, they send out radiation.

    Again; I'm just speculating here, as it is not my field of expertise.
  4. Aug 21, 2009 #3
    From the textbook, "Transport Phenomena" by Bird, Stewart, and Lightfoot;

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