Mechanical waves are the disturbances in a medium (solid, liquid or gas) by which energy is passed on but no matter. They need a medium through which to multiply. The waves propagate through the vibration of the particles of the medium about their rest positions, the energy passing on one particle to the next, either parallel (longitudinal) or perpendicular (transverse) to the wave direction.
Examples Sound waves (longitudinal), water waves (transverse).
