When a low-energy photon collides with an atom in the ground state, if the energy gap between the atom's levels exceeds the photon's energy, the photon may either pass through without interaction or be scattered, resulting in a slight change in direction. If the medium absorbs the light, it can convert that energy into heat, leading to an increase in temperature. Infrared light, which has lower energy, is typically absorbed by molecular rotational or vibrational modes rather than atomic transitions. This absorption occurs only if the medium possesses such modes; otherwise, it remains transparent to infrared light. The discussion highlights the relationship between photon energy, atomic transitions, and the resulting thermal effects in various media.