5 Metronomes on board and cans sync their oscillations
• B+15+20

Five metronomes sit on a light foam board that rests on top of two empty soda cans that can roll. The metronomes are set to oscillate at the same frequency, but at the start they are out of sync with each other. After a minute or so, the back and forth movement of the board on the cans causes the metronomes to all sync with each other. Thanks to the Harvard Natural Sciences Lecture Demonstration for the original idea.
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