No one can answer this question. Physicists will tell me that an electron moves based on its energy level. Or some other mumbo-jumbo... but WHY WHY WHY???? Why do electrons move AT ALL? What is the purpose? You could say kinetic energy is the trade-off of all the other kinds of energies, but that isn't answering the question- it is only avoiding it. Movement is something that is unneccessary and meaningless but for some reason, particles MUST move, in order to express the energy that they hold. Otherwise, they wouldn't interact with other forces and wouldn't have mass, spin, position, velocity or any other characteristics necessary to be MATTER. Still, I must ponder... why do electrons move at ALL??