Chladni figure

What it means

A Chladni figure, or sound figure, is a pattern made visible by vibration on a vibrating surface. If fine sand or similar material is scattered on a metal or glass plate and it is set vibrating, for instance with a violin bow, the material gathers at the still points of the plate, the nodal lines, while moving away from the vibrating areas.

Musical use

Chladni figures are named after the German physicist Ernst Chladni, who systematically investigated them around 1800, making an important contribution to acoustics and the theory of vibration. The resulting patterns depend on the shape, material, and point of excitation of the plate, and vividly illustrate how complex vibration modes and overtones arise. Chladni figures are still used today in physics teaching to make vibration phenomena visible.

The Chladni figure should be distinguished from the pure sound wave, which propagates invisibly through the air, and from purely acoustic concepts such as interference or resonance, which describe phenomena of sound propagation without necessarily producing a visible pattern.

Performance practice

If you produce a Chladni figure yourself, aim for an even distribution of sand and a controlled excitation of the plate, for instance at a fixed point with a bow. Observe how the pattern changes as you vary the point of excitation or the pitch, to recognise the relationship between frequency and vibration mode.