Book 14, Question 123
Why Does Sand Make Patterns on a Vibrating Plate?
Sand makes patterns on a vibrating plate because some parts shake and some parts stay still! The sand bounces away from the shaking parts. It ends up on the still lines, and draws beautiful patterns.
More fun facts
- Sprinkle sand on a metal plate, make it vibrate, and patterns appear.
- Sand bounces off the parts that are moving and collects on the parts that stay still.
- These still lines are called nodes.
- Physicist and musician Ernst Chladni came up with the sand idea in 1787, and the shapes are called Chladni figures.
- Robert Hooke saw similar patterns on vibrating glass plates back in 1680.
- Chladni even made a formula that predicted the patterns on round plates.
Sources: Smithsonian, Scientific American, Exploratorium
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