Chladni patterns are visual representations of the nodes of vibrations setup in the a surface while it is subject to a specific frequency. This and more on modern acoustics is found in Chapter 5 of Erik Jansson’s publication “Acoustics for Violin and Guitar Makers” here. A good overall description of Chladni patterns can be found on the New South Whales University website here.
Ernst Florens Friedrich Chladni has been around a while and published a book on the patterns seen in vibrating plates in 1787. His original publication is on Google Books here, however, a knowledge of old German and a Ph.D. in physics are prerequisite. It’s reported that his interests in the patterns were inspired by George Christoph Lichtengberg’s earlier experiments on electrical figures. Interest in this visual representation of sound waves was such that Chladni demonstrated it for Nepolean in 1809. A plate of the image of Chladni is seen below .
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