Sound physics

Sound is a vibration that propagates as an acoustic wave

Sound that is perceptible by humans has frequencies (acoustic waves): - 20 Hz to 20,000 Hz (audio frequency range)

In air at atmospheric pressure, wavelengths of sound waves range: - 17 m (56 ft) to 17 mm (0.67 in)

Sound waves above 20 kHz are known as ultrasound and are not audible to humans. The particles of the medium do not travel with the sound wave

Citations: - https://en.wikipedia.org/wiki/Sound#Waves