Longitudinal & Transverse Wave

A longitudinal wave is one in which the vibrations are parallel to the direction of travel of the wave.

A transverse wave is one in which the vibrations are perpendicular to the direction of travel of the wave.

Longitudinal waves:
sound waves

Transverse waves:
water waves,light waves& electromagnetic waves

Transverse waves:
waves on a string and electromagnetic waves

Longitudinal waves:
sound waves

http://en.wikipedia.org/wiki/Longitudinal_wave
http://en.wikipedia.org/wiki/Transverse_wave