The Mathematics of Refraction Snell's Law Refraction is the bending of the path of a light wave as it passes across the boundary separating two media.
Refraction is caused by the change in speed experienced by a wave when it changes medium.
The more that light refracts, the bigger the difference between these two angles. In this part of Lesson 2, we will learn about a mathematical equation relating these two angles and the indices of refraction of the two materials on each side of the boundary. To begin, consider a hemi-cylindrical dish filled with water. Suppose that a laser beam is directed towards the flat side of the dish at the exact center of the dish. The angle of incidence can be measured at the point of incidence.