Why does refraction occur at the boundary between two medias?

Light travels in waves. Media's have different densities. The waves slow down when the move into a denser medium. The waves at the back are still moving fast but the front waves are moving slower. This causes them to bunch up. read more

Media's have different densities. The waves slow down when the move into a denser medium. The waves at the back are still moving fast but the front waves are moving slower. read more

The masking tape is analogous to a boundary between two media. The change in speed that occurred for the line of students would also occur for a wave of light. And like the marching students, a light wave will not undergo refraction if it approaches the boundary in a direction that is perpendicular to it. read more

Refraction occurs any time light goes from one medium into another and the two mediums have different refractive index. The refractive index [math]n[/math] is the factor by which the speed of the light slows down relative to the speed of light in vacuum [math]c_0[/math]. read more