Sound waves do not propagate instantly. This can be seen in the case of thunder and lightning: they both occur simultaneously, but first see lightning and then hear the thunder. This is because the light is faster than sound. In air, sound travels at a speed of 340 meters per second, ie 1224 miles per hour. The rate decreases as the medium becomes less dense. Therefore, at higher elevations the air becomes less dense and the propagation speed of sound decreases. In water, the sound acquires a speed of 1,504 meters per second. Through metals such as iron, spread to 5127 meters per second and, in some types of steel, to 6080 meters per second. As sound travels in waves need an elastic medium that vibrates as the world's water, air from the atmosphere or soil. Therefore, the sound does not propagate in vacuum.
The sound barrier is formed when the velocity of an object is close to acquiring the sound in that medium.
At a speed of 1,504 meters per second.