## Cymatics – Seeing Sound

Cymatics are a subset of vibrational phenomena which describe the motion of a material under a vibrational signal. Typically a material i.e a liquid, paste or group of particles are placed upon a plate of arbitrary shape. Different shapes are formed by the material as the surface of the plate is vibrated. The nature of the shape depends on the geometry of the plate and the driving frequency of the vibration.

The phenomena was observed by notable scientist Robert Hooker in 1680 as he saw nodal patterns emerge in flour when applying a vibration across a glass plate. This method was improved upon by German Musician and Physicist Ernst Chladni. He noticed that the vibration could be used to visualise the resonance of musical instruments. He achieved this by drawing a violin bow across a plate covered with a fine dust (sand/flour) until the plate reaches resonance. The phenomena observed can be explained using classical physics. When the plate is vibrated, the dust will always travel to a point of zero vibration. This is because the dust follows the path of standing waves along the nodal lines of the plate. The dust will move away from the antinodes, where standing wave amplitude is at a maximum, and toward the nodes where standing wave amplitude is at a minimum. These form the patterns known as Chladni patterns. These can take many different shapes depending on frequency mode and plate shape

Two Chaldni patterns on the same plate under different frequency modes

The applications of Cymatics and Chladni patterns present a huge potential in the fields of contemporary music and art. For example, the 2022 Eurovision competition uses Cymatics in its logo and poster.

The principles of formation of Chladni patterns can also be extended to liquids and dusts in 3-D orientations. The following video is a perfect example of such, and the fusion of science and music.

Cymatics are certainly an interesting facet of physics that shows the link between sound and vibrational motion.

1. Pg 101 Oxford Dictionary of Scientists- Oxford University Press- 1999
2. Forrister, How do chladni plates make it possible to visualize sound, COSMOL, 2018