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I Infrared radiation from friction

  1. Jul 3, 2017 #1
    Hello all,
    I was driving down the road yesterday, and I realized that I don't really have a solid grasp on how frictional forces cause infrared radiation. Can anyone explain, or direct me to a resource that explains, how this happens at the atomic level?

    I am thinking that the work done forcing the two surfaces together, against the EM forces, gives energy to the individual electrons, which move to a higher state, and then they release photons as they transition back to a lower state, but this is the oversimplified model I have in my head and is probably wrong.

    Any help is appreciated.
  2. jcsd
  3. Jul 3, 2017 #2
    Friction causes heat.
    Heat causes IR. Low heat, thermal IR. More heat near IR. More still, visible glowing.

    Also, when friction causes sparks to fly - those sparks are material torn from the surface and raised to high temperatures.
  4. Jul 3, 2017 #3


    Staff: Mentor

    @.Scott gave you the answer. Heat is more than electrons changing energy states. You need to study how molecules and crystal lattices change behavior with temperature. The next step is how do solid bodies radiate as a function of temperature.

    If you want to think it through one particle at a time, you'll have enough to keep your mind occupied for many many miles of driving. :rolleyes:
  5. Jul 3, 2017 #4
    Ok, so should I rather consider the surface as a mass of oscillators already releasing IR, and then the friction increases the amplitude of the oscillations?
  6. Jul 3, 2017 #5


    Staff: Mentor

    I would start with black body radiation. That is what is at the root. The article offers several models for what is happening.


    It can get very complex.

  7. Jul 3, 2017 #6
    Thanks Anorlunda. I think where I am going wrong is that I am attempting to develop a conceptual model for these friction interactions where I am regarding light as a particle, but these interactions may only be able to be modeled with light regarded as a wave.
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