How does heat travel? I have two competing thoughts here!!
Firstly some form of atomic/molecular process liberates a photon in the infrared region of the spectrum which is detected as heat by a sensor.
Secondly thermal excitations and the what not propagating through matter causing an increase in the average kinetic energy and hence a temperature rise.
Heat is just the change in entropy with respect to temperature, so how do I unify these ideas? (sorry if its basic)