Wave physics ( Part 3 )

What is the sound wave?
Propagation of displacement (expansion and condensation) or change of pressure in the elastic environment due to disturbance (collision, etc.)

What are the conditions for the formation (production) of sound waves?
(1) Disorder
(2) Existence of equilibrium conditions

What are the conditions for sound wave propagation?
(1) Existence of medium
(2) Environmental elasticity
(3) System coupling with the medium

* The denser the medium, the faster the sound wave propagates.