Sound waves are waves that are created by oscillations of vibrating energy through various substances. Sound waves can pass though gasses, liquids and solids. As sound waves pass through air, the air molecules oscillate back and forth parallel to the direction of the wave. This back and forth motion creates a longitudinal wave. A longitudinal wave has oscillations that are in the same direction as the traveling wave.
Sound waves are used to carry information and energy over long distances. When sound waves propagate through the air they transport vibrations our ears. Our ears pick up theses vibrations and process them as music. In a similar way radio waves carry information to a stereo which then translates it into sound via its speakers.
Almost anything that vibrates can produce a sound. When something vibrates it pushes the air molecules around it. This push then occurs in all directions around the vibrating source. Energy is then transferred (Hsu Tom, 2003). This in fact is the concept of force: force = pressure x area, which represents a push.