Waves that require a medium for their propagation are called mechanical waves or elastic waves. The particles of the medium execute periodic motion about a mean position when the wave propagates through the medium.
For Example, waves on a string
A mechanical wave is produced due to a disturbance at a point in a medium.
- The disturbed particle interacts with the neighbouring particle and its energy is handed over to the next particle (due to the inertia of the medium).
- The disturbed particles return to the equilibrium position (due to the elasticity of medium).
Properties of Medium for Mechanical Wave Propagation
- The medium must possess inertia so that its particles can store kinetic energy.
- The medium must possess elasticity.
- The minimum frictional force between the particles of the medium.
Non-Mechanical Waves
Waves which do not require a medium for their propagation are called a non-mechanical wave. These types of waves can propagate through vacuum also. These are transverse in nature. For example, electromagnetic waves and matter waves.