Here’s a cool little science-y blog for y’all:

As each metronome reverses its direction at the top of its swing, the energy is transferred to the platform below and, through the platform, to the other metronomes. At first, these transferred energies are all out of sync and the different waveforms interfere with one another. This continues until balance is eventually created, meaning that the interference pattern is a standing wave and is causing the metronomes to be “locked” into sync with one another.

Even that little rebel on the right.

Cool, huh?
[haha, get the title? ‘Tik Tok’ like metronomes going “tick-tock? I’m not TOTALLY crazy*.]

[*debatable]