Properties of sound waves When an object or substance vibrates, it produces sound. These sound
waves can only travel through a solid, liquid or gas. They cannot travel through empty space.
Longitudinal waves are the vibrations are in the same direction as the direction of travel. Sound
waves are produced by all vibrating objects. Loudspeakers work by converting electrical energy into
kinetic energy. This moves the cone which creates the sound waves. Sound waves are produced by
all vibrating objects. Loudspeakers work by converting electrical energy into kinetic energy. This
moves the cone which creates the sound waves.