http://www.ck12.org Chapter 12. Waves and Energy Transfer
12.2 Longitudinal Waves
- Describe longitudinal waves.
Playing with a Slinky is a childhood tradition, but few children realize they are actually playing with physics.
Longitudinal Waves
Like transverse waves,longitudinal wavesare mechanical waves, which means they transfer energy through a
medium. Unlike transverse waves, longitudinal waves cause the particles of medium to move parallel to the direction
of the wave. They are most common in springs, where they are caused by the pushing an pulling of the spring.
Although the surface waves on water are transverse waves, fluids (liquids, gases, and plasmas) usually transmit
longitudinal waves.
As shown in the image below, longitudinal waves are a series of compressions andrarefactions, or expansions. The
wavelength of longitudinal waves is measured by the distance separating the densest compressions. The amplitude
of longitudinal waves is the difference in media density between the undisturbed density to the highest density in a
compression.