Question

Pleasant sound is termed as music when vibrations produce waves in irregular patterns? Why?

Answer 1

Hint: Sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid.

Complete answer:
Sound can propagate through mediums such as air water and solids as the longitudinal waves and also as a transverse wave in solids. The sound is generated by a sound source, such as the vibrating diaphragm of a stereo speaker. The sound source creates vibrations in the surrounding medium. As the source continues to vibrate the medium, the vibrations propagate away from the source at the speed of the sound, thus forming the sound wave.
Noise is generated when the sound frequencies are in continuous and irregular manner. However, musical sound has frequencies in discrete and rational form. In musical sound wave patterns are periodic and regular.
Therefore music is a pleasant sound produced by regular wave patterns. The mechanical vibrations that can be interpreted as sound can travel through all forms of matter: gases, liquids, solids and the medium. Sound cannot travel through a vacuum. Sound can be viewed as a wave motion in air or the other elastic media. In this case, sound is a stimulus. Sound that results in the perception of sound, in this case sound is a sensation.
Additional information:
Sound is transmitted through gases, plasma and liquids as longitudinal waves, also called compression waves. It requires a medium to propagate. Through solids however it can be transmitted as both longitudinal waves and transverse waves. Longitudinal sound waves are the waves of alternating pressure derivation from the equilibrium pressure, causing local regions of compression and refraction, while transverse waves are the waves of alternating shear stress at the right angle to the direction of propagation. Sound waves are often simplified to sinusoidal plane waves.

Note:
During the propagation waves can be reflected, refracted or attenuated by the medium. The behaviour of sound propagation is generally affected by three things:
A complex relationship between the density and the pressure of the speed of the sound with the medium. This relationship affected by the temperature, determines the speed of sound with the medium.
Motion of the medium itself. If the medium is moving, this movement may increase or decrease the absolute speed of the sound wave depending on the direction of the movement.