Twenty vials of mercury form a wave

Twenty small vials hang from springs. Marcel Clemens poured slightly different amounts of mercury into them, so each oscillates at its own frequency. After a simultaneous start, waves and more complex patterns gradually emerge from the individual movements.

Mercury serves as a weight here: its high density allows for the use of small vials, and a liquid is easy to measure out for precise tuning of the mass. No wave is transmitted from neighbor to neighbor — the pattern arises from the difference in frequencies.