Way back in September of 2007, I posted some links to the bizarre world of ferrofluid, illustrating how fluids can interact with magnets (often magnets driven by sound -- like speakers) to create strange, seemingly gravity-defying patterns. Today I bring you a TED Talk about Cymatics, which is the process of making sound visible, sometimes using special fluids -- ferrofluids among them. (Cymatics often also uses other physical media like sand to make visible patterns.)
In this brief (roughly five-minute) talk, artist Evan Grant demonstrates how he uses Cymatics to create bizarre and beautiful art, along with a brief a brief history lesson on the field. Worth it if you just like looking at cool/weird stuff, or if you're interested in the science behind sound and resonance.
For best video quality, check it out in high resolution here (MP4 link), or just click below: