32 out-of-sync metronomes synchronize with each other by themselves

[Donna]

http://youtu.be/JWToUATLGzs   

[Bonnie]

Donna, you are crazy.

[Shaky]

Notice that the "bridge" beneath the metronomes is oscillating in time with them. This is why soldiers break cadence when marching across a bridge.

[Donna]

Donna, you are crazy.

Who ME??    I know!

[Donna]

Notice that the "bridge" beneath the metronomes is oscillating in time with them. This is why soldiers break cadence when marching across a bridge.

Ya know.....I did not notice, so now you punish me by watching it all over again!!! 

[dale]

Notice that the "bridge" beneath the metronomes is oscillating in time with them. This is why soldiers break cadence when marching across a bridge.

I've heard about that, with soldiers; it was explained as having something to do with a frequency that mechanically resonated with the bridge and could make it fall. Does that make sense?  I'm wondering in this case if some fuzzy initial majority tendency got the table moving in a way that influenced more and more of them? In other words, maybe it happened because of a subtle movement of the table?

[Dumpsterkitty]

Notice that the "bridge" beneath the metronomes is oscillating in time with them. This is why soldiers break cadence when marching across a bridge.

I've heard about that, with soldiers; it was explained as having something to do with a frequency that mechanically resonated with the bridge and could make it fall. Does that make sense?  I'm wondering in this case if some fuzzy initial majority tendency got the table moving in a way that influenced more and more of them? In other words, maybe it happened because of a subtle movement of the table?

I had seen another similar video once. I believe the explanation was something along the lines of the vibration of the table, resonating at the same frequency, is what eventually brought the metronomes into synch. I'll have to dig this weekend...

[Shaky]

Notice that the "bridge" beneath the metronomes is oscillating in time with them. This is why soldiers break cadence when marching across a bridge.

I've heard about that, with soldiers; it was explained as having something to do with a frequency that mechanically resonated with the bridge and could make it fall. Does that make sense?  I'm wondering in this case if some fuzzy initial majority tendency got the table moving in a way that influenced more and more of them? In other words, maybe it happened because of a subtle movement of the table?

A modern, well maintained bridge wouldn't fall from marching over it, but old bridges built centuries ago could. Also, any bridge suffering from war damage could fall. (Imagine that -- soldiers marching across a bridge during a war.)

I've felt the High Falls pedestrian bridge vibrate form just one person jogging across it, and that bridge was built over a century ago.

[Dumpsterkitty]

OK...needing to let my geek out...

http://youtu.be/Aaxw4zbULMs

Five metronomes are set to 176 bpm and placed on a Foam Core board. When empty cans are placed underneath, the board is free to move from side to side and the metronomes are able to influence each other into synchronization. When the cans are removed the metronomes are no longer physically coupled and some of them begin to fall out of step.

Our demonstration is a copy of one that Bryan Daniels (Ohio Wesleyan University) made for his student research work: http://go.owu.edu/~physics/StudentResearch/2005/BryanDaniels/index.html

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http://www.math.pitt.edu/~bard/classes/mth3380/syncpapers/metronome.pdf

Synchronization of metronomes
James Pantaleone
Department of Physics, University of Alaska, Anchorage, Alaska 99508
(Received 1 April 2002; accepted 24 June 2002)
Synchronization is a common phenomenon in physical and biological systems. We examine the
synchronization of two (and more) metronomes placed on a freely moving base. The small motion
of the base couples the pendulums causing synchronization. The synchronization is generally
in-phase, with antiphase synchronization occurring only under special conditions. The metronome
system provides a mechanical realization of the popular Kuramoto model for synchronization of
biological oscillators, and is excellent for classroom demonstrations and an undergraduate physics
lab. © 2002 American Association of Physics Teachers.

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OK...I feel better now!

[Donna]

Far-out Ei!!   

[MAK]

Fascinating! 

[dale]

OK, thanks, Ei!!
That's what I was wondering - if some fuzzy initial majority created a movement of the table that in turn encouraged more metronomes to be timed as it was, which in turn increased the movement of the table.
very cool...