A particle in the ground state of a potential well can only gain energy by making a transition to one of the higher allowed energy levels. Let's consider this well to be a 1 dimensional infinite potential well with the electron bouncing between the walls of the well with certain discrete energies. Two questions: Is the energy level diagram just a pictorial representation of the varying quantised energies that the electron can possibly have? If we were to view this electron, if it jumped to another energy level, how would this manifest itself into something we could observe, ie if it moved to some higher level, would we simply observe the electron moving faster between the walls of the well? Many thanks.