Sound on the move
When sound comes from aboard a slow-moving boat, the sound waves spread out evenly through the water, where they move even more quickly than in the air. When the sound comes from a plane, the pattern of sound waves is quite different. This is because the plane moves much more quickly, 'catching up' the sound waves that it makes.

Sound in the air : Sound travels through the air at abut 330 m (1082 ft) a second. It move slightly faster on a warm day than on a cold one.

Underwater sound : Sound travels nearly four times faster in water than it does in air. This means that a fish will hear the boat before a person standing nearby it on land.

Chasing sound : Most passenger jets move at about two-thirds of the speed of sound. At this speed, a plane keeps catching up the sound waves in front of it, and race away from the one it leaves behind. These trailing waves make a low-pitched rumble as the plane flies away.

Fading out : As the sound waves travel outwards, their energy is slowly soaked up by the air. Eventually, they become too weak to be heard. This is why it is hard to make yourself heard a long way off, even if you shout.

Tag :moving sound