Scientists Say: Refraction | Science News for Students

Scientists Say: Refraction

When a wave such as light or sound passes through a material, sometimes it has to bend
Sep 25, 2017 — 6:50 am EST
refraction prism

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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Power Words

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angle     The space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.

density     The measure of how condensed some object is, found by dividing its mass by its volume.

glass     A hard, brittle substance made from silica, a mineral found in sand. Glass usually is transparent and fairly inert (chemically nonreactive). Aquatic organisms called diatoms build their shells of it.

Plexiglas     or plexiglass The first is the trademarked name (the second is a more general name) for the chemical poly(methyl methacrylate) . It’s a transparent plastic that can resist shattering. It can be used in place of glass for many applications.

prism     A triangular wedge of glass or another clear substance that can bend the components of white light into a rainbow-like succession of colored bands.

rainbow     An arc of color displayed across the sky during or just after a rain. It’s caused when water droplets in the atmosphere bend (or diffract) white sunlight into a number of its component hues: usually red, orange, yellow, green, blue, indigo and violet.

refraction     The change in direction of light (or any other wave) as it passes through some material. For example, the path of light leaving water and entering air will bend, making partially submerged objects to appear to bend at the water’s surface.

sound wave     A wave that transmits sound. Sound waves have alternating swaths of high and low pressure.

transparent     Allowing light to pass through so that objects behind can be distinctly seen.

wave     A disturbance or variation that travels through space and matter in a regular, oscillating fashion.

wavelength     The distance between one peak and the next in a series of waves, or the distance between one trough and the next. Visible light — which, like all electromagnetic radiation, travels in waves — includes wavelengths between about 380 nanometers (violet) and about 740 nanometers (red). Radiation with wavelengths shorter than visible light includes gamma rays, X-rays and ultraviolet light. Longer-wavelength radiation includes infrared light, microwaves and radio waves.

wood     A porous and fibrous structural tissue found in the stems and roots of trees, shrubs and other woody plants.