Explain propagation of sound waves in solids.

Explanation

Crystalline solids possess lattice structure in which atoms or molecules are arranged with some definite geometric periodic pattern. In the normal condition, without any disturbance, all these atoms or molecules are under equilibrium because forces exerted from surrounding balance each other.
Now, under this equilibrium condition, if disturbance is produced in any atom or molecule, it gets displaced from its equilibrium position. Here this atom or molecule behaves as it is elastically connected to neighbouring atoms or molecules. Hence, restoring force is developed in such imaginary elastic springs. Such a force becomes responsible for producing very small oscillations in the atoms or molecules, turn by turn along the direction of motion of disturbance which ultimately results into propagation of wave in the solid medium from one end to another end.