Question

What causes sound ?

Answer 1

Hint:Sound is mainly defined as a type of energy which needs medium to travel. They are produced by vibrating bodies in a medium which creates disturbance in the medium. They travel in the form of mechanical waves.

Complete answer:
When a body vibrates it produces a disturbance in the surrounding medium. Let us take the medium as air which has particles in motion with compression and rarefaction. These particles get disturbed by the vibrating body and we hear sound.Sound can also be defined as the form of wave which is created by a vibrating body and the surrounding medium through its particles helps it to propagate.

The number of oscillations made by wave per unit time is defined as the frequency of sound waves and has S.I. unit as Hertz(Hz). Wavelength of a sound wave is the length of one complete oscillation and the time taken to complete one oscillation by sound wave is it’s time period. So sounds are basically produced by vibrating bodies which creates pressure difference in the surrounding medium which helps sound to travel.

Note:Sound energy always needs a medium to travel. Sounds are not heard in vacuum. Sounds above \[20000Hz\](ultrasonic sound) and below \[20Hz\] (infrasonic sound) cannot be heard by humans but most of the animals can.