How Does Refraction Work?

The path of a photon is determined by the wave equations that are guiding its motion through the electromagnetic field. For example, if you have a straw in your glass of water, it looks like the straw is sort of broken in half because the part of the light that's going through the water gets bent slightly in a new direction. That's what we call refraction. Two photons hitting a surface might bend in slightly different directions, but a bunch of photons hitting the surface sort of average out to give you the answer you would expect from the wave equation. So everything is like making sense and being continuous.