Propagation of Sound
Sound is produced by the rapid to and fro movement of an object i.e. vibration. The object set to vibration disturbs the equilibrium state of the particles in the medium and vibration keeps transmitting from one particle to another. e.g. when a tuning fork is struck against a rubber pad vibration created in the prongs can be noticed and brought near our ears we can sense the sound being produced, guitar strings produce sound when struck, etc.
The traveling of sound from the sound source to the surrounding medium is the propagation of sound. Sound waves cannot travel in a vacuum as there are no molecules present to set vibration.
Speed of Sound in Different Mediums
The average speed of sound is 343m/s. Sound travels in the form of waves from one medium to another. Speed of sound varies in different mediums. It is affected by factors like temperature, density, elasticity of the medium through which sound waves travel. We have listed the speed of sound in different mediums in the table below:
|
Materials |
Speed of sound |
|
Air at 20° C |
343 m/s |
|
Rubber |
60 m/s |
|
Lead |
1210 m/s |
|
Gold |
3240 m/s |
|
Glass |
4540 m/s |
Can Sound Travel in a Vacuum or Space?
Sound always requires a medium to travel from one point to another. Sound cannot propagate in a vacuum because there are no particles or molecules present to set vibration. The music produced by the vibration of guitar strings can be heard as the vibration produced travels through the air to our ears. In this process air acts as a medium of transmission of sound.
How is the Sound Heard by Humans?
Sound waves traveling through a medium reach our ears, and we hear the sound. As the sound waves are gathered by the pinna of our ear and then lead to the ear canal where they strike the eardrum. The vibration set from the eardrum is transmitted to three bones (hammer, anvil, stirrup) and finally to the inner ear. The sensitive cells present in the inner ear transmit the vibration to the brain through the auditory nerve which is registered as sound by the brain.
Read More,
Production and Propagation of Sound
Have you ever wonder how are we able to hear different sounds produced around us. How are these sounds produced? Or how a single instrument can produce a wide variety of sounds? Also, why do astronauts communicate in sign languages in outer space? A sound is a form of energy that helps in hearing to living beings. It is a form of kinetic mechanical energy which moves in a form of a wave. The sound waves show vibrational motion. Hertz (Hz) and Decibel (dB) are widely used measurement units to measure sound.