# How Do You Calculate Wave Speed & Wavelength?

A wave is created when a vibration disturbs the first particle of a medium. The vibration then creates a wave pattern that travels from particle to particle in the medium. The crest of the wave is the point at maximum positive or upward displacement from the rest position. The trough is the point at maximum negative or downward displacement from the rest position. The period of a wave is the time it takes for a particle to move upward from rest, back to rest, downward from rest, and back to rest. This is one complete wave cycle. The frequency of a wave is measured in cycles per second or Hertz (Hz). Determine the wavelength. Measure the distance between the crest of one wave and the crest of the next wave or between the trough of one wave and the trough of the next wave. This measurement is the wavelength (λ). Calculate the frequency or the period of the wave. The frequency and the period are reciprocal of each other, therefore: Period (T) = 1/Frequency (f) Frequency (f) = 1/Period (T)