Speed Of Sound Waves In Solid

Sound waves are caused by the vibrations generated through the medium and are longitudinal waves. These waves contract and expand the medium’s sections in alternating patterns. The speed of the sound wave depends on the characteristics of the medium that it propagates. The sound waves cannot travel through a vacuum, but they are able to propagate through solids, liquids and gases. 

Speed of sound 

The distance travelled by the sound waves through an elastic medium per unit of time is termed the speed of sound. The particles of the medium travel parallel to the sound waves as it propagates through the medium. The speed of the sound wave depends on the characteristics of the medium that it propagates. The medium’s density and elasticity play an important role in determining the speed of the wave, and in a given medium, the speed remains constant. But it does not depend on the characteristics of the wave or the force that is applied.

The formula for the speed of sound is written as-.

v = f.λ

where, v= velocity, f= frequency and λ= wavelength

Speed of sound in solid

Unlike the light waves, the sound waves require a medium to propagate from one point to another. The speed at which the sound waves travel through a solid medium is termed the speed of sound in solids. To create an energy pattern, the sound waves transfer energy from one particle to another during propagation. The particle matter in solids is closely bound; therefore, the energy transfer is easier and faster in solids.

Depending upon the medium, the speed of the sound wave varies. It cannot travel through a vacuum. In solids, the particles are effective and close together, creating a good force for the energy to transfer rapidly and easily through the medium. Due to this, the speed of sound in solid is higher compared to gases and liquids. The processing of the sound once it enters the solid medium also plays a vital role. For example, sometimes, the medium absorbs the energy that is getting transferred and then dampens the sound. These types of mediums can be used to design sound barriers or sound dampeners.

Mathematical expression for the speed of sound in solids-

The speed of the sound wave depends on the elasticity and density of the medium. The elasticity that is generated by the longitudinal stress is called Young’s Modulus. The solids can react to the energy coming in two different ways. The compressions are created, which is called shear deformation, and the force that is experienced in this case is called Longitudinal and shear forces.

So, the mathematical expression for the speed of the sound in solids is given by:

v =√(Y/ρ)

where,

v → Speed of sound in the solid

Y → Young’s modulus of the solid depicts the density of the medium

ρ → Density of the solid

The behaviour of the sound waves towards the medium can be determined by its velocity. The energy transfer in the solids is higher as compared to liquids and gases. The particles of a solid medium can collide with each quickly as they are closely packed. Therefore, the speed of sound in the solids is 6000m/s. The solids are stable molecules and near proximity due to their mass. The interesting fact is that the speed of the sound waves is 35 times faster in diamonds than in the air. The bonding of particles in the solids is much stronger than the gases and liquids, so the sound travels faster in the solid medium.

Conclusion-

The elastic properties of the solids contribute majorly toward the behaviour of the solid medium. The denser medium generates a lower speed of sound than the rarer medium. The measurement of the speed of sound has a major role in construction, engineering and various other scientific purposes. It is used to determine the high energy sound waves in the construction or building sites.  It helps in studying the effects of tectonic plates on the buildings. 

The disturbances caused by the sound waves are determined while designing the space vehicles, astronomical types of equipment, etc. This is done to find out the way to reduce the impact of harsh sound waves on the instruments used.