Kinetic Chain Sculpture Built From a Bicycle





Introduction: Kinetic Chain Sculpture Built From a Bicycle

I took an old bike, scavenged a 12-volt car seat-motor from another project to power it, and ran chain around the rear rim. I find it so mesmerizing it's almost dangerous to turn it on; I might spend an hour watching the various shapes travel through the moving chain. I didn't realize how cool this project would be until I had actually built and tested it.

Though this phenomenon is probably best described by pages upon pages of differential equations, my best simple explainantion is this: Think of a length of chain hanging and not moving. If you hit it, something like a wave will propagate away from the point at which you struck. Now fix yourself to a point on the chain, start it moving, and hit it again. From your perspective the wave propagates as before, at equal speed in both directions, yet from the perspective of a fixed external observer, the wave's speed and the chain's speed add in one direction along the chain, and subtract in the other. So for chain speeds close to the wave speed, waves will appear to sit at the same relative position or to move slowly along.

This "slowing down" effect is one of the reasons why I am so fascinated. In the moving chain, shapes that would otherwise change too fast to enjoy can be clearly seen.

The Exploratorium has a similar exhibit called the Lariat Chain.



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    might I suggest using some sort of rod to manipulate the chain instead of your fingers. hate to see them sliced off. other than that very very cool.

    Not a bad suggestion, but the low-wattage motor tended to stall easily and really couldn't do any harm.

    These are great, my local science museum has a 10 foot one with thicker chain.

    I made one out of knex once but the chain can only form shapes in one plain so it's not as impressive.

    read the comments..dont you guys think making it work with black light would be cool..its like everything is dark except a glowing chain with weird patterns

    COOL !!
    love the way it looks slow motion
    whats the rpm of the wheel?

     Haha, i love the socks with flip flops in the second vid.

    Hey, I am building a pedal generator bike with a battery. at the end of the day i want to transfer the electricity i made of riding into a bigger battery and then use it for lighting equipment... anyone knows of a method to transfer the electricity from one battery to a bigger one without losing voltage or too much energy???

    What type of chain is that? I've seen similar things in a smaller scale using string in a hand held device.

    It's the chain that looks like a bunch of small hallow balls connected by straight pieces of metal. You can just make it out in the slideshow images.