Electromagnetic spectrum

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   David Meyer (dmm@mathstodon.xyz)'s status on Wednesday, 08-May-2024 08:27:34 JST David Meyer

   I've been studying harmonic oscillators [1] and that led me to blackbody radiation which in turn led me to try to understand how heat transfer works. Here's one of the interesting things I've noticed in this process:

   Apparently there are three possible mechanisms for transferring energy: conduction, convection, and thermal radiation.

   In the case of conduction in a solid, energy is carried through an atomic lattice by free electrons or by phonon–phonon interactions (i.e., excitation of vibrational energy levels for interatomic bonds). In gases and liquids, energy is transferred from molecule to molecule through collisions (i.e., the faster molecule loses some of its kinetic energy to the slower one).

   Heat transfer by convection is similar, except that here many of the molecules with raised kinetic energy are carried away by the flow and are replaced by colder fluid (low-kinetic-energy molecules), resulting in increased energy transfer rates.

   So both conduction and convection require the presence of a medium for the transfer of energy.

   Thermal radiation, on the other hand, is transferred by electromagnetic waves, or photons, which may travel over a long distance without interacting with a medium. The fact that thermal radiation does not require a medium for its transfer makes it of great importance in vacuum and space applications.

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   #blackbodyradiation #electromagneticspectrum #physics