Vibrating plates create stunning Chladni patterns. Sand gathers at nodal lines — the places where the plate doesn't vibrate. Different frequencies produce different geometric patterns.
The plate vibrates at eigenfrequencies. Sand moves away from antinodes (maximum vibration) and collects at nodes (zero vibration), revealing the mode shape.
Change the vibration frequency to see different patterns emerge. Higher frequencies create more complex, intricate figures.
Ernst Chladni demonstrated these patterns to Napoleon in 1809 using a violin bow on metal plates. Napoleon was so impressed he funded Chladni's research — making it one of the first government science grants.