When light travels from one medium to another, three phenomena can occur; reflection, refraction, and dispersion. Reflection takes place when the light does not pass into the material, but is instead "bounced" off the surface. Refraction occurs when the light passes into the material. It is bent toward or away from the normal according to the index of refraction of the material. The normal is a line perpendicular to the surface of the medium. Dispersion occurs when different wavelengths of light are refracted different amounts, separating the light into its constituent colors. The wave property of light prevents all light from passing directly though a medium. As light passes through different mediums, part of it is reflected and part is transmitted through.

When light travels from one material to another, it is refracted, obeying Snell's Law. This law states that the sine...