As the only metal that is liquid at room temperature, mercury is freaky even under normal conditions. But check out what happens to a blob of the stuff when it's exposed to a different audio frequencies.
Photographer Nick Moore achieved this cymatic effect by pouring the mercury onto a concave plastic lens from an old projection TV (it was only about one-centimeter across). The lens was then stuck to a 12-inch speaker using Silly Putty to prevent it from rattling around or bouncing. The sine wave tones, ranging from 10 Hz to 120 Hz, were produced by an old signal generator.
And as you can see, when frequency is increased, more nodes, or bumps, appear on the mercury as it resonates — a result of its exposure to three-dimensional standing waves.
Here's what it looks like in slow-motion:
H/t Mental Floss.