Chladni figures
They are the drawings sand makes on a vibrating plate. Every resonant frequency has its figure, and every figure tells you how the plate is moving.
Nodes and antinodes
A plate free to vibrate does not move as a single block. At certain frequencies a standing wave sets in: some regions swing widely, others stay still. Grains bounce off the first and settle on the second, tracing the nodal lines.
The figure is therefore a portrait of the plate rather than of the sound: it describes the vibrational mode that the note excited.
The round plate
Circular plates can display radial lines and rings. Which modes appear depends on geometry and support; there is no universal sequence for every disc.
The app pairs ten round illustrations with targets at 105, 162, 251, 335, 435, 538, 630, 765, 860 and 965 Hz. These are illustrative model presets, not certified measurements from a laboratory plate.
The square plate
The app includes square illustrations such as an X, grids and diagonal patterns, built with illustrative formulas. Mode names label the model; they do not certify a real plate’s vibration.
The nine square-pattern targets are 138, 245, 352, 420, 485, 585, 695, 810 and 935 Hz. They support the simulation and do not predict every physical plate’s response.
Why your plate will give different numbers
Frequencies and modes depend on stiffness, thickness, dimensions and support. Compare real experiments by recording these conditions alongside the measured frequency.
This is why no universal table of cymatic frequencies exists, and why any catalogue must always name the plate it refers to.
Observe a physical plate
Interpret an experiment by considering support and excitation points alongside the nodal lines. Symmetry alone cannot certify material quality or uniformity.
Frequently asked questions
Why does sand stop on certain lines?
Because those lines, called nodes, are where the plate does not move. Everywhere else the vibration keeps the grains jumping until they find a still area.
Do the figures depend only on frequency?
No. They also depend on the shape of the plate, the material, the thickness and how it is clamped. The same note on different plates gives different figures.
Can I see them without sand?
Yes, with a simulation. Cimatica animates illustrative models; it does not measure or exactly solve a physical plate.