Last week I stumbled upon that beautiful pendulum video. In comments, Max shared another cool video from the same people (Harvard Natural Sciences Lecture Demonstrations) – about synchronizing metronomes: (Thanks Max!)
The audio effect is important; watching the metronomes isn’t as powerful as hearing them get in a rhythm.
Any variation between the metronomes results in energy “swaying” the system, leading them to synchronize over time. After all, you wouldn’t expect a metronome to keep perfect time if you were shaking it – the setup just makes the shaking work against metronomes going against the consensus. I’m sure our friends at Ask a Mathematician/Ask a Physicist could give a more thorough answer.
What surprised me is that they got OUT of synch after being removed from the soda cans. I thought that, once in a rhythm, they would stay that way. I guess that by picking the system up and putting it back on the table was enough to break that. Or am I missing something?