Bringing the Universe to America's Classrooms
Describing a Wave

The Wavelength of a Wave

Another way to describe a wave is by its length. The length of a wave is called the wavelength. All waves have a wavelength. This diagram shows how to measure the wavelength.

The wavelength is the distance between each peak or between each trough.
A labeled diagram of waves.
A line cuts across the middle of an up and down shape of a curvy line that represents waves. The line that cuts across the middle is called “the resting position.” The top part of a wave is called the peak. The bottom part of the wave is called the trough. The wavelength of a wave is shown as the distance from one peak to the peak next to it. The wavelength is also shown as the distance from one trough to the trough next to it. The distance from peak to peak is equal to the distance from trough to trough.

Produced by