Hello, Guest! Sound is the vibration of the air, the so-called longitudinal audible waves. They propagate in the air at a speed of about 330 meters per second. This is much less than the speed of light. That is why, when thunderstorms, we first see a flash of lightning, and only then, with a delay of several seconds, we hear thunder. Sound waves propagate not only in the air, but also in other media, in liquids and solids. The speed of sound in water is about 1500 meters per second.