For a layman that is close enough and you have got it that the process is atomic/molecule level.
It has to be because in classical physics when you measure temperature (heat) with a thermometer etc it is translated as the kinetic energy of movement speed of the molecules/atoms in the gas/solid/liquid not the speed of the electrons around the orbitals (energy levels of the electrons) in the atom/molecule.
In classical physics the explaination involved with thermal radiation is that if you take a gas of atoms/molecules and confine it to a region of space (solids and liquids do that automatically) containing some radiation field with some characteristic temperature, the atoms and the radiation will eventually come to some equilibrium in which the kinetic energy distribution of the atoms and the frequency spectrum of the radiation will have the same characteristic temperature.
In that explaination lies the fact the radiation and the kinetic energy are both forms of energy and are actively connected.
The problem for classical physics is there exist no formula and no explaination for the connection and hence no reason for the shape of the spectrum. If you assume they are connected your mathematics will fail as that shape is very strange it has some very strange properties.
What Planck did was work out that if one makes a premise of a resonant vibration that has distinct steps (quantization) the mathematics gives you that shape of emission. So his logic was there must be a resonant connection between the molecule/atom kinetic energy and the thermal spectrum (AKA light) and that set the stage to then try and measure and quantify that connection, what it is and how it works.
Planck had removed a foundation stone of classical physics and it largely went unnoticed for another twenty-five years until classical physics would ultimately collapse as it would be connected to other inconsistencies that were found.
Last edited by Orac; 07/10/16 03:14 AM.
