How Does Light Travel Through a Glass Prism?

For What Do We Use Glass Prisms?

To learn how light travels through a glass prism, you first need to know the function of the glass prism. When light travels through air, it travels very quickly. A glass prism is much denser than air, so when the light beam travels through the prism, it slows down significantly, allowing the light to refract.

What's Refraction?

When discussing how light travels through a glass prism, you'll often hear it said that the light "refracts." That simply means that the light bends. White light is actually made up of many frequencies of colored light, each with its own wavelength. These different wavelengths cause each color to refract (or bend) at a different angle.

How Does Light Travel Through a Glass Prism?

The white light goes from the air to the denser glass prism. This slows the light enough that the colors of which the white light is comprised refract. The angle of refraction depends on each color's wavelength. Because a color's wavelength is always the same, you'll see that each color refracts at the same angle. That means the colors coming from a prism are refracted in the same rainbow-like order every time.