When one adds water to a Tibetan singing bowl and plays – often by tracing the edge with a mallet – the bowl’s haunting sound is accompanied by ripples on the water’s surface. That’s because the mallet pushes on the side of the bowl – made from bronze alloy that is more malleable than glass – and deforms it on a microscopic scale.
The deformation pushes on the air and the water, forming waves. The air waves are sound; the water waves race around the ring. If they are sufficiently excited, the waves break and eject droplets. The same happens in a wine glass, though at higher resonant frequencies.