The Rough Guide to Gas

How can we find rock shapes?

Selina SeagullScientists have found that you can find the shape of underground rocks by making a noise, and listening for how the sound bounces back. It is a bit like the way bats know where they are going using very high-pitched sounds.

The sound you hear bouncing back is called an echo.

Is there an echo in here?

sound bounces off a solid wallIf I fly some distance from cliff and call to Sidney, I can hear an echo. You might notice it in front of a large wall; don't try flying in front of a cliff!

If you are the length of a football pitch away from the wall, about 100m, it will take just over half a second for the sound to travel there and back again. Sound travels a lot slower than the speed of light.

Echo survey

Sound travels through liquids and solids, as well as through the air, and will bounce back from places where the material changes; on the sea bed, or from different layers of rock underneath. This is used to help find the rock shapes that might contain gas or oil.

If you want to find out more about echoes, you could try this echo practical activity...

Let's see how a boat uses echoes to help find oil and gas...