Geisha bowl

Imagine that you want to wash your face, but are not allowed to put your hands into the water. Is it possible?

If you wet your hands and rub them against the handles of the bowl it starts to vibrate, creating waves in the bowl. After a while, the water will come splashing up. Like the waves in narrow waters where the sea is choppy, which makes the waves start to crash into each other.

The resonance frequency of the bowl is what creates the wave pattern. Resonance phenomena are created with all types of vibrations and waves. There is mechanical resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance, electron spin resonance and resonance from wave functions in quantum mechanics. Resonant systems can be used to create vibrations of a certain frequency, for example in a guitar. When you play the guitar, the strings create a wave motion that is reinforced by the construction of the guitar: the body, the bridge, the nut, and the different tensions on the strings.

It is said that the most distinguished Japanese geishas were not allowed to dip their hands into the water to wash themselves. By rubbing the handles of the temple bowl and leaning forward they could wash without touching the water.