I hear frequently that light is simply an oscillating electric field. But I have problems visualizing this. Mostly because I'm a mech. engr. and I have a tendency to always try to picture something physically in my head to help me understand it. I simply can't do it when I think about light this way. When you think of a mass on a spring, you can think of it's oscillating position with respect to some point in space. But when I try to translate that to light I always think, "well what's the actual quantity that is oscillating"? and also "what is it oscillating with respect to"? I'll typically think of it as a light bulb and an eye ball next to each other. If it is an oscillating electric field, then is the light bulb and eye simply point charges oscillating between positive and negative at the broad frequency of white light? This obviously sounds ridiculous when I repeat it to myself. Then usually I think of it as 3D wave, like sound, where the quantity that is oscillating in all directions is air pressure. Neither of these thought experiments help me understand what light actually is at all obviously. Help!