Mercury Wave

Marcel Clemens made what he calls a mercury wave. Small bottles are suspended on springs, each of them carrying a slightly different amount of mercury. When the springs are released all at the same time, they move up and down at slightly different speeds to create fascinating patterns. This looks like a pendulum wave, but it's different in a few ways. 

At first, I watched and thought the springs were different lengths due to a diagonal line at the top of the frame, but watching in a larger format reveals that's a shadow. The difference between each unit is the weight inside. There's nothing magical here about mercury; Clemens used it because it's heavy and liquid, so each amount can be precisely measured. This video shows the pattern repeating once, and Clemens tells us it played out four times over about five minutes before all the bottles came to rest. If you are geeky enough to want the math, a few of his comments at YouTube might interest you.  (via Geeks Are Sexy)