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 ...

Refraction occurs when light changes direction as it passes, e.g., from air into water or glass. Negative refraction, however, is a counterintuitive effect where light in a medium bends in the ...