Propagation of Sound

Let Us Learn About Propagation of Sound

Sound Propagation

Sound propagates through air as a longitudinal wave. The speed of sound is determined by the properties of the air, and not by the frequency or amplitude of the sound. Sound waves, as well as most other types of waves, can be described in terms of the following basic wave phenomena.

Reflection of Sound

The reflection of sound follows the law "angle of incidence equals angle of reflection", sometimes called the law of reflection. The same behavior is observed with light and other waves, and by the bounce of a billiard ball off the bank of a table. The reflected waves can interfere with incident waves, producing patterns of constructive and destructive interference. This can lead to resonances called standing waves in rooms. It also means that the sound intensity near a hard surface is enhanced because the reflected wave adds to the incident wave, giving a pressure amplitude that is twice as great in a thin "pressure zone" near the surface. This is used in pressure zone microphones to increase sensitivity. The doubling of pressure gives a 6 decibel increase in the signal picked up by the microphone. Reflection of waves in strings and air columns are essential to the production of resonant standing waves in those systems.

Sound is a kind of sensation received by our ears and sensed by our brain. sound is produced when an object vibrates with small amplitude. Sound can be produced by vibrating strings, membranes, air, tuning fork. A vibrating object which produces the sound has a certain amount of energy which travels in the form of sound waves. The substance through which the sound travels is called medium.The sound propagation is done by using medium.

Propagation of Sound

For sound propagation, it needs a medium. The medium needed by sound to propagate must be a material medium, elastic and continuous. Sound waves in air consist of compression and refractions of air. When a person speaks, the air closer to his mouth is pushed in the direction of sound. The air molecules get distributed and startibrating about their mean position. Such molecules which vibrate will disturb the nearest molecules for vibrating them. Continue this method until the molecules starts vibration which is nearer to listener. This causes the vibrations in the diaphragm of the ear.