Wind gongs

What you can do here
Caution: if you hit the gongs too hard they may crack or break!
Remember never to hit the centre of the gong. This may damage the instrument.

Hit the larger gong with a mallet. Listen to the sound you have produced. Hold your hand close to the gong surface without touching it. You will feel the vibrations of the air that surrounds the instrument. Move your hand around to examine how the vibration intensity changes with the position. Repeat the above after hitting a different spot on the gong. Repeat the experiment with the smaller gong.

How it works
A two-dimensional standing wave propagates through the gong when it is hit. This kind of acoustic wave causes local disturbances of air density, which – apart from acoustic sensations – may also be sensed by your body.

Interesting facts
The gong came to mediaeval Europe from South-East Asia. Its name comes from the Malay. Orchestras introduced it in the late 18th century.