Light bends when travelling through a concentration gradient of sugar in water. The top layer of liquid is pure water while the bottom layer ... In the tank, from top to bottom, the index of ...

A ray diagram showing refraction at the boundary between air and glass Refraction can cause optical illusions as the light waves appear ... such as water, it slows down and wavelength decreases.

It is refraction that makes some objects appear to bend when they are viewed through water, like the straw shown here. If the light hits the surface of a glass block at an angle, this change in ...