Scientists Say: Refraction

When a wave such as light or sound passes through a material, sometimes it has to bend


This animation shows how refraction divides white light as it passes through a prism into a rainbow of color.

Lucas V. Barbosa/Wikimedia Commons

Refraction (noun, “Re-FRAK-shun”)

This is a change in the direction a wave travels when it enters a new substance. The wave could be a light wave, a sound wave or any other kind of wave. For example, when a light wave passes from air into a triangle of glass, called a prism, the higher density of the glass causes the light wave to slow and bend. The refraction separates the various wavelengths of light. The separation causes them to leave the glass triangle at slightly different angles. Because each wavelength corresponds to a different color to our eyes, the glass separates a white light into a rainbow of colors.

In a sentence

If a board of wood and plexiglass is thin enough, it may allow light through without refraction — making it appear clear and transparent.

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Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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