Download PDF – Sound: Production and propagation

Production of Sound :

The basic way for the production of Sound is “vibration”. When an object vibrates it produces sound.

It can be produced by plucking, scratching, rubbing, blowing, flapping, or shaking different objects, as while doing each mentioned activities vibration is produced among the particle of that object.

“Vibration” is a kind of rapid to and fro motion of an object. For example – stretching of a rubber band, a vibration of string, or surface of any musical instrument.

How does sound propagate :

Vibrating objects produce sound.

The matter or substance through which sound is transmitted from the point of generation to the listener (starting point to ending point) is known as a medium, which can be solid, liquid or gas.

The particles of the medium do not travel all the way from the vibrating object to the ear.

For instance – when we speak the particle in the air gets displaced due to the pressure caused by the production of sound, which again exerts pressure on other adjacent particles and this process continues till the intensity of vibration gets over or the sounds reach our ears.

Sound needs a medium to travel :

Sound needs a material medium to propagate like air, water, steel, etc. The most common medium through which sound can travel is air. It cannot travel through a vacuum (no air) due to the unavailability of disturbances in the medium.

 At the time of propagation of sound when a vibrating object moves forward, it creates Region of High Pressure which is known as compression (C).

With alternate regions of compression, there is also a region of low pressure, which is produced when the vibrating object moves backward and this region of low pressure is known as a rare fraction (R).

As the object moves backward and forward consecutively, a series of compression and rarefaction will be created in the air which will ultimately form sound waves that will produce sound.

Pressure is related to the number of particles of the medium in a given volume or its density.

If the medium is dense, the pressure exerted by the particles of the medium will be more and vice versa.

Thus, propagation of sound is all about change in pressure of the medium.