A wave It is a movement that propagates with a certain periodicity in a vacuum or in a physical environment. According to their characteristics, the waves are classified differently.

The mechanical waves they advance through an elastic medium, whose particles They oscillate around a fixed point. The medium in question can be gaseous, liquid or solid.
With the mechanical waves there is no net transport of matter. The gravity waves and the sound waves are examples of mechanical waves.
For a mechanical wave to exist, it is necessary that there be a source that generates the disturbance and a means by which said disturbance can spread. In addition, a physical environment is needed that allows the elements to influence each other.
Take the case of sound . This sensation It is produced in the ear from the vibration of the bodies, which is transmitted by air or by other elastic means. The oscillations of the air pressure cause sound waves that, in the ear, are transformed into mechanical waves that the brain then perceives.
When the mechanical wave travels, in short, it generates an oscillation that affects the equilibrium state of a mechanical property from the middle, like the Pressure , position or density. There is a source emitting the fluctuation, which extends from that point to the contiguous ones.
As the means, medium It is elastic, the disturbance separates the first point from its equilibrium position and makes it vibrate. The elasticity then causes it to spread to a second point, then to a third point and so on, developing a transverse wave.