What are Sound waves ?
Sound travels as vibrations moving through the air as a compressional (longitudinal)wave.
Sound travels through air , but travels through other materials as well. Whale communicate through long distances by producing sounds under water.
What are Mechanical Waves ?
A mechanical wave is a periodic disturbance, which requires a material medium (solid, liquid or gas) for its propagation. These waves are also known as elastic waves because their propagation depends upon the elastic properties of the medium through which they pass. Examples for mechanical waves are sound waves and water waves. In these waves, the particles of the medium just vibrate to and fro about their mean position.