How Do Prisms Work?

Dear Sara,

Prisms are real, but they seem magical because of the way they seem to contain so many different colors of light. How do prisms work?

You’re referring to the kind of prism that optically refracts light. (A prism is also a geometric form that’s a type of polyhedron, and a geological term for a type of sediment deposit.) An optical prism has flat, polished surfaces in a multi-sided shape (typically but not always a three-dimensional triangle, or pyramid) that takes what the eye would normally see as transparent or white light and breaks it down into its component colors along the primary/secondary color spectrum. Light changes speed as it moves from air to glass (or any other physical medium), which causes the refraction when the light “bends.” Sir Isaac Newton did experiments that proved prisms did not create colors, but simply displayed colors that were already present but hidden to the naked eye.

It’s In The Bag,
Sara Bellum, Editor-at-Large Buzzy Mag