Chladni figures

Definition:

Chladni figures are visual patterns that appear when a plate sprinkled with sand or another fine powder is vibrated. The patterns appear at the points where the plate does not vibrate (the so-called nodal lines), while the sand is thrown away from the vibrating areas (the vibration bellies).

Origin:
The German physicist and musician Ernst Florens Friedrich Chladni (1756-1827) discovered the Chladni figures in 1787. Through his research, he founded the field of acoustics and is often referred to as the "father of acoustics".

Origin:
The Chladni figures are created by sprinkling a thin plate with sand and then sweeping a violin bow along the edge or by exciting it with a loudspeaker or other exciter at different frequencies. The vibrations that occur at certain frequencies (the natural frequencies of the plate) lead to the formation of stable vibration modes in which characteristic patterns are formed.

Significance and application:
Chladni figures are not only used to illustrate and research vibration physics, but also have applications in modern scientific and engineering disciplines. They are used to investigate the resonance properties of materials and components and serve as teaching aids in physics.

Literature and links:
More information on Chladni figures on Wikipedia
YouTube video demonstrating Chladni figures

Further topics:

Acoustics
Resonance
Vibrations
Physics of musical instruments

Sources:
Ernst Chladni: "Die Akustik" (1802)
Various scientific articles and textbooks on vibration theory and acoustics