Sand forms intricate geometric patterns on a resonating metal plate in this demonstration of the Chladni plate experiment by Brusspup. To run the experiment, Brusspup placed a metal plate on top of a speaker that was attached to a tone generator. At certain frequencies the metal plate resonates, causing the sand to collect along “nodal lines” where the metal is not vibrating. Science!
For a similar resonance demonstration, see this sound visualization by Japanese artist Kenichi Kanazawa.