Answer by Viktor T. Toth, IT pro, part-time physicist, on Quora: Why do we call photons 'particles'? Aren't they all electromagnetic waves? In the classical theory of electromagnetism, Maxwell's, there are no photons. read more
It is these units of excitations of the electromagnetic field that we call photons. Like other quantum particles, they are not really “particles” like miniature cannonballs. Rather, they represent the smallest indivisible unit of interaction with the field. read more