Physics Classroom
The Physics Classroom: Optical Density and Light Speed
A tutorial page explaining how the speed of light is dependent upon the optical density of the material through which it moves. Optical density is related to the index of refraction; sample values are given.
Physics Classroom
The Physics Classroom: Refraction and Ray Model of Light: Direction of Bending
In this interactive physics tutorial about refraction, students investigate the topic of the direction of bending of a light wave.
Physics Classroom
The Physics Classroom: Refraction and Ray Model of Light: Refraction by Lenses
Students use this tutorial to investigate the refractive ability of converging and diverging lenses.