Hit rock slabs one after the other. Listen to their sound. Check how the produced sound depends on the place where you hit the slab. Find the relationship between the size of a slab and the pitch of the produced sounds.
How does it work
When you hit a rock, it is excited to vibrations. Vibrations are the source of acoustic wave which propagates in the air and reaches our ears. The smaller the rock, the higher the sound produced.
Why is this happening
Lithophone – rock xylophone – is one of the first musical instruments. The oldest preserved lithophone found in Vietnam is over 6 000 years old. Instruments of this kind are still used in some regions of Asia and Africa.