self_synchronizing_metronomes.mov

Several metronomes set at the same frequency but running initially out of phase self-synchronize due to the coupling permitted by a freely rolling base.

M1

To set up:

1. wind up the metronomes fully
2. place metronomes on top of the board on the marked locations
3. release the metronomes
4. place styrofoam board on top of the cans, which should be placed near the ends of the board
5. observe as they match modes (note, you can get an out of phase metronome out of the five; this is possible since this is another stable solution; try adjusting the positions until you get the completely in phase solution)
6. for fun, you can set the second and fourth metronomes at a different frequency (second and fourth are equal, though) from the other three - which have same frequency. you will get the normal modes for an alternating two mass system

PIRA DCS 3A70.XX