Moving air

How does the exhibit work?

Beat the drum with your flat hand. The mirrors on the other side will start moving.

What is the science behind it?

Do the mirrors move through sound?

No, they don’t! Just stand next to the mirrors and ask someone to beat the drum. You will hear the beat before the mirrors start to swing! Sound travels so fast that it reaches the mirrors after only one hundredth of a second. The mirrors move because of the wind made by the drum. It takes about a second for it to reach the mirrors.

A wind of 34 metres per second is already called a hurricane, while sound reaches 340 metres per second in the ai

Speed of sound in water

Do you think sound travels fast in the air? In water, it travels four times faster: about 1,500 metres per second. Many animals that live underwater communicate using sound.

Speed of sound in thunderstorms

Sound may travel at a tremendous speed, but it is nothing compared to the speed of light. Light travels 300 000 km per second.

You can see that light travels faster than sound during a thunderstorm. Thunder is the sound that accompanies lightning. However, you always see the lightning first and then you hear the thunder. If you want to determine your distance from the lightning, start counting after the flash and stop when you hear the thunder: every three seconds corresponds to about one kilometer.

Speed of sound for aircrafts

If an aircraft flies faster than the speed of sound, a very loud bang is produced. They also say that the aircraft “breaks the sound barrier".

You also hear such a sonic boom when you strike with a whip.