#1 - Waves caused by two types of force.

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The force in an ordinary wave.

In the ordinary waves, the force is of a mechanical kind.

For example, the passage of a boat starts a thrust, which takes the form of a series of ordinary waves. Another example, the wind.

In the case of ordinary waves, the thrusts between molecules are given by a mechanical energy, external to the molecules, which is transferred from one molecule to another, from point A, to point B, one way, barring obstacles.

The wave then consists of ephemeral variations between the molecular spaces, following chain thrusts, at the time of the passage of energy, which, from the outset, has always been mechanical.

The occupation of space of each individual molecule does not change; the spaces between molecules change; it is the variation of these spaces that gives the sense of movement.

The force that causes the density waves.

On the other hand, in water figures in general, and in density water waves, the rhythmic variation of the density of water is induced by “the force d” at critical angular velocity values with respect to other matter, including that of the Moon and the sun.

This would be due to changes in the molecular configuration of water, thanks to processes now in the cumulative sense (volume decrease), then in the dissipative sense (volume increase).

This is at least my interpretation.

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