Part of Questacon's Science in Slow Motion series.
For a look at the science, click "show more".
The tines of a tuning fork vibrate back and forth only a small distance, but at great speed. When you put a struck tuning fork into a glass of water, the fast-moving tines splash water out. You can see a similar effect on a larger scale if you move your hand quickly whilst it's just submerged in the top of the water in a bath or pool.
