A wavelength is a measure of the distance between two consecutive peaks or troughs of a wave. It is usually measured in meters. The wavelength of a wave determines its frequency, which is the number of waves that pass a given point in one second. The higher the frequency, the shorter the wavelength.

Wavelengths can be seen in many different phenomena, such as light, sound, and water waves. In light, the wavelength determines the color of the light. The shorter the wavelength, the higher the frequency and the bluer the light. The longer the wavelength, the lower the frequency and the redder the light.

In sound, the wavelength determines the pitch of the sound. The shorter the wavelength, the higher the frequency and the higher the pitch. The longer the wavelength, the lower the frequency and the lower the pitch.

In water waves, the wavelength determines the size of the waves. The shorter the wavelength, the smaller the waves. The longer the wavelength, the larger the waves.

Wavelengths can be measured using a variety of instruments, such as a spectrometer, an oscilloscope, and a ruler.