Longitudinal Waves
Waves carry energy from one place to another - either via the movement of particles (mechanical waves) or by electromagnetic means - Longitudinal waves are only mechanical waves - no electromagnetic wave is longitudinal.
There are two types of wave: transverse and longitudinal - see here for information on transverse waves.
The vibrations in a longitudinal
wave are parallel to the direction in which the energy is
travelling. Eg. sound waves.
![](longitudinal.gif)
Because the vibrations are along the same line as energy transmission longitudinal waves cannot be polarised.