Longitudinal waves
With sound waves, the energy travels along in the same direction as the particles vibrate. This type of wave is known as a longitudinal wave, so named because the energy travels along the direction of vibration of the particles.
Producing longitudinal waves using a spring:
Step 1
A hand holding a stationary spring stretched horizontally
Step 2
A hand jerked forward to produce a compressed area in the spring
Step 3
A hand jerked back to produce a stretched area in the spring
Step 4
The compressed and stretched area in the spring travel along its length. The wave travels from left to right, and the particles of the spring vibrate horizontally.