Direction of particle displacement

Depending on the direction of its oscillations, a mechanical wave can be:

1. Longitudinal: Particle displacement is parallel to the direction of wave propagation.

   Figure: Longitudinal Wave, animation courtesy of Dr. Dan Russell, Kettering University.

   

2. Transverse: Particle displacement is perpendicular to the direction of wave propagation.

   Figure: Transverse Wave,animation courtesy of Dr. Dan Russell, Kettering University.