The more dense the medium the slower the speed of sound.

A more dense medium has more atoms per meter to cause delays.

This can obviously make light appear to travel slower in a dense medium.

Material particles are simply bubbles of nothing, moving about in this dense, elastic, granular medium.

We know that a dense medium is necessary for the best control of ultrasonics.

But thirty million cycles, apparently, can be controlled in air, in a medium less dense than our atmosphere.

They moved slowly, sluggishly, as did the Tellurians, in that thick, dense medium which was not, could not be, air.

This wave in the optically less dense medium is known as the evanescent wave.

This is because the light immediately scatters when it hits such a dense medium.

The difference between the two that gravity separation does not use a dense medium to operate, only water or air.