The Physics of Sound

Sound is percussive vibrations through air, water, or some other medium. The energy of a sound wave pushes molecules out of their resting place between two points called a crest and a trough.

The distance from the resting point to a crest or trough is called the amplitude, or in music, the volume. The distance from crest-to-crest or trough-to-trough is called the wavelength. The amount of time it takes the wave to traverse one cycle (a full wavelength) is called a period, and the number of cycles per second is described as the frequency, or in music, the pitch.