Law of refraction
Refraction of light occurs when light passes from one medium to another, which usually involves a change of direction. The angle of incidence and the angle of refraction are related by Smell's law. Observe the result of changing the angle of incidence and the index of refraction.
Change of medium I
In this simulation you can observe the different parameters involved in the refraction of a light ray when changing medium.
See what happens when you pass light through a material other than air. Try changing to different shapes and see how light behaves differently in each case. Why does white light break down into colors?