Thanks to CemenTIMental for pointing me towards my new favourite website. Spark Bang Buzz is a great collection of science experiments, many of which are music-connected. The guy makes photocells out of bits of copper oxide, builds his own vacuum tubes and makes a sound-reactive laser from 4 components. One of the best bits is this page, where he generates "Peculiar Sounds from a Drop of Saltwater on Aluminum" - and these [400kb .wav] are those sounds.