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Why doe glass get hot if the photons aren't absorbed?

  1. Aug 31, 2012 #1
    My understanding of glass is that it is transparent because photons do not have enough energy to raise the electrons in the atoms to the next energy level, thus the photon is not absorbed thus it gets through and we see it as light.

    But if the photon isn't absorbed, thus not leaving it's energy behind in the glass and, how come glass till gets hot on a summers day? If the light has retained it's energy?
  2. jcsd
  3. Aug 31, 2012 #2


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    1. While glass is transparent in the visible range, it is not transparent always. Ordinary glass (as opposed to quartz or fused silica) is opaque to UV. And IR is absorbed by almost everything, including glass. So there are certainly EM radiation from the sun that isn't transmitted through glass.

    2. While it is transparent, the transmission isn't 100%! So even in the visible region, there will still be light absorbed through glass.

    3. A solid is different than an isolated atom. The "exitation" in a solid" isn't just "electrons going to next energy level", because in a solid, there is a "vibration" mode. It is this vibration of the lattice ions of the solid that can cause the solid's temperature to change. And EM radiation can interact with such vibration.

  4. Aug 31, 2012 #3
    Ahhh it was staring me in the face. Knew there would have been a simple answer, thanks a lot.
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