Parts of a sound wave
The crest is the highest point in a sound wave. A wavelength is the length between one crest the other or from one trough to the other. The amplitude of a sound wave is the measurement from the rest point to the crest. The compression is the point in a sound wave where the particles are close together. The expansion is the point in a sound wave when the particles are spread out.
What is the amplitude of a sound wave?