Question #f48ec
1 Answer
Light is not refracted inside a crystal ball.
Refraction takes place at the boundary between two materials with different optical densities. Refraction of light takes place as the light goes from the air into the glass or from the glass into the air. Inside a solid piece of glass, light simply moves in straight lines. The light does move a tiny bit slower in glass than it does in air. And it's actually this difference in the speed of light which causes refraction.
If the ball is simply a solid glass sphere of uniform density it can be thought of as a simple lens. However, it is a simple lens with lots of aberrations; both spherical aberration and chromatic aberration. Simply put, that means that it magnifies things but distorts and blurs the images a lot.
This excellent image is from a report by Kira Schultheiss at Stonybrook University.
