Speed of Sound in Solids and Liquids

Solids and liquids are not easily compressible. When sound waves displace the constituent particles in these media, they display a tendency to restore to their original positions due to interparticle forces.

Recall that sound is a pressure wave. It travels through a medium as its constituents vibrate about their mean positions and transfer the energy to neighboring particles.

If the constituent particles are massive, it is harder to restore them to their original positions. Hence, the speed of sound through a medium is lower if its constituents are heavier.

Combining these concepts, the speed of sound in solids and liquids is given by the square root of the elastic modulus divided by the density of the respective medium.