Characteristics of sound waves: Vibration of an object produces sound waves. Elastic inert media are required to conduct sound waves. The sound is called a mechanical wave. This wave is a longitudinal wave because the direction of flow and direction of vibration are the same. The speed of sound waves depends on the nature of the medium. Its velocity is less in gaseous medium , more in liquid , more in solids. The intensity of sound is proportional to the square of the wave propagation. That is, the higher the wave propagation, the higher the sound intensity. Sound waves are possible to reflect , refract and overlap. The speed of sound also depends on the temperature and humidity of the medium.