When we vibrate a simple metal plate at specific frequencies, the physics of sound becomes visible as geometry.

Here you are seeing sound shaping grains on a metal plate into what are known as Chladni figures. When the plate vibrates, some regions move intensely while others remain almost still. The grains are shaken away from the moving areas and settle along the quiet lines, the nodes, revealing the pattern of each vibration mode.

Each frequency produces a distinct arrangement, and as the pitch increases, the patterns become more intricate. Mathematically, these figures are normal modes of vibration, solutions of the same wave equations that describe musical instruments, ultrasound, and many mechanical responses in biological tissues.

Experiments like this show that what we call “form” is often the visible record of how energy is distributed in a system over time, from metal plates and membranes to organs that constantly respond to pressure, flow and rhythm.