Waves for Kids: Amplitude and Wavelength Explained (Grade 4 Science)

Hi, I'm Luna from DoodleBeez. Drop a pebble into a calm pond and watch the ripples spread out in rings. Those are waves! Today we will learn the parts of a wave and how to measure them.

A wave carries energy from one place to another. In water, the water mostly bobs up and down as the wave passes. The energy travels forward, but the water itself stays in nearly the same spot.

The top of a wave is called the crest. The bottom of a wave is called the trough. Waves go up and down in a repeating pattern: crest, trough, crest, trough.

Amplitude tells how tall a wave is. We measure it from the calm middle level up to the crest. A wave with a big amplitude carries more energy, like a giant ocean wave crashing on the shore.

Wavelength is the distance from one crest to the very next crest. Short wavelengths mean the waves are packed close together. Long wavelengths mean the waves are spread far apart.

Water waves are not the only kind. Sound travels in waves through the air, and light travels in waves too. They all have their own patterns of amplitude and wavelength.

Now it's your turn. Wave A has crests two meters apart. Wave B has crests five meters apart. Which wave has the longer wavelength? Pause and try. Wave B, because its crests are farther apart!

Great job! Remember, waves carry energy. The top is the crest and the bottom is the trough. Amplitude is how tall a wave is, and wavelength is crest to crest. Practice waves in the Science Lab at doodlebeez.com. See you next time!