http://www.youtube.com/watch?feature=player_embedded&v=JWToUATLGzs#!

http://www.youtube.com/watch?feature=player_embedded&v=JWToUATLGzs#!



Neat! Obviously the moving floor is the key, but still really cool.

Can you explain more about the moving floor for those of us who are not scientifically inclined?

The floor is on a gimbal which creates a slight rocking to the movement of the base. The weights on the metronomes will affect the center of gravity of the platform, and its travel arc speed, and ultimately come into synchronis movement. This would not happen on a fixed, level surface.

What happens when they run down?

great explanation!

They stop. No?

This variation on that theme is cool, too...

reminds me of Ligeti.

Do you chaps know what a gimbal is? Marty does.

“A gimbal is a pivoted support
that allows the rotation of an object about a single axis.” (so sayeth Wikipedia)

Presumably the earthly globe does it’s gimbal twirl ...
"about a single axis" ...
without shaking the leaves off the trees.

Always good to pick up a new word ... must save it to impress at my next cocktail party.

Of course they stop. (I'm stupid, but not that stupid!)

Do they stay together as they run down or does the synch. come apart?

Oh dear, oh dear, oh dear!

Well, we've now gone from physics to clockmaking. It would depend on the escapement energy in the clock mechanism in relation to inertia/mass. That is, the mechanical energy stored within the spring to be released in a repetitive sequence. The synchronis movement would continue until the springs/escapement could no longer affect the "whole." Once you have less than 50% of the metronomes in action, they would start to go out of synch as they would no longer contain sufficient stored energy to affect the "dead weight" of the stopped ones through the movement of the base.

I would think that they pretty quickly run out of sync, since each one is a somewhat crudely constructed mechanical device, and the inherent tension in the spring that drives each will be slightly different.

I would also be very surprised if I were told that a minimal number of mechanical metronomes from the same manufacturer would beat at exactly the same tempo when set at the same tempo on a stable surface. I presume that mechanical metronomes are not manufactured to very high standards, that there are probably infinite variations in the quality of assembly and even in such things as the mass of the weight and the precise positions of the tempo markers on the bar.

Regards,

btb - Here's another cocktail party word for you:

Horology - It's great when someone is flashing a new Rolex!

Not horophilia?

hmm...

I would say that the platform is moved by the force of the springs in the metronome. As it pulls the pendulum to the right that creates a reactive force to the left (and vv)

Center of gravity does not seem to be relevant to me.

They will stay together at one frequency.