Wind gongs

What can you do here
Caution: striking the gongs too hard may cause them crack or break!

Hit the larger gong with the mallet. Listen to the sound you have created. Hold your hand close to the gong surface without touching it. You will feel the vibrations of air that surrounds the instrument. Move you 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 does it work
A two-dimensional standing wave propagates through the gong when its disc is struck. This kind of acoustic wave causes local disturbances of air density, which – apart from acoustic sensations – may also be sensed by our body.

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