The compressions and expansions of air in a sound wave are described in the window below. The animation on the right of the window illustrates how sound waves travel and how the compressions and expansions map to a sinusoidal function.
The human range of hearing is described in the window below. Human hearing may detect frequencies from 20 Hz to 20,000 Hz. The animation on the right plays a tone as it increments through the detectable frequencies of human hearing.
To listen to a tone played across frequencies in the human hearing range, press the sound button for the appropriate audio format.