Here's a question from my textbook. Since there are no calculations I put this in this forum rather than the hmwk forum. When light (or other electromagnetic radiation) travels across a given region, what is it that oscillates? What is it that is transported? Here is the answer provided: Energy moves. No matter moves. You could say that electric and magnetic fields move, but it is nicer to say that the fields stay at that point and oscillate. The fields vary in time, like sports fans in the grandstand when the crowd does the wave. The fields constitute the medium for the wave, and energy moves. I thought it was the photon that moves. Maybe I'm thinking of the photon as a particle when it's not really a particle but only has particle like properties.