Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Infrared and heat

  1. Sep 23, 2007 #1
    How exactly is infrared associated with heat? Is it just that infrared waves are emmited out of our body and when they contact something they turn to heat rather then being reflected?
  2. jcsd
  3. Sep 23, 2007 #2


    User Avatar
    Science Advisor
    Gold Member

    All bodies radiate energy. The frequency (or, equivalently, the wavelength) depends on the temperature.
    This is described by Planck's law


    It turns out that a body held at a temperature of about 300K (i.e. room temperature) will emitt radiation with wavenlengths that are in the infrared region of the EM spectrum (the maximum will be at a wavelength of a few micrometer).

    This also means that you can measure the temperature of a body by measuring its spectrum.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook