Mechanical waves require a medium to travel through so that they can transmit energy. Some examples of mechanical waves are water waves, sound waves and the waves of a slinky or jump rope. The medium through which a mechanical wave moves through can be a fluid, solid or gas.
Mechanical waves can be either longitudinal or transverse waves. While a longitudinal wave is a wave in which the medium's displacement is parallel to the direction of the wave's propagation, a transverse wave is a wave that vibrates in a perpendicular at a right angle direction to the direction of the wave's propagation. An example of a longitudinal wave is a sound wave moving through air. A string wave is an example of a transverse wave.