Zoetrope

I've previously noted how a zoetrope uses a series of still pictures to trick your brain into seeing movement - essentially the same thing that happens in a movie projector. Here is a zoetrope of a galloping horse by Lego Tron. The galloping horse is a particularly appropriate subject (as Lego Tron notes), because it hearkens back to the work of Eadweard Muybridge. Muybridge was a photographer who was interested in seeing how animals move. In a famous experiment, he set up a series of cameras along a racetrack that were triggered to snap photos as a horse galloped past. These pictures could be strung together in an early version of a motion picture, similar to the zoetrope, called a zoopraxiscope. These pictures also proved that at points during the gallop, all four feet were in the air at once. BTW, I first learned about the Muybridge work after Ahmed Zewail won the 1999 Nobel Prize in Chemistry, since he compared his work to Muybridge. Zewail used extremely short (femtosecond) bursts of laser light to "photograph" a reaction in motion, and actually characterize something at (or very near) the transition state. In comparison to the Muybridge work, this is like being able to sit and study the horse with all four feet in the air. Of course you normally can't do that, since the horse would fall to the ground, but you can study the photograph that captures that moment in time. A transition state (which is a point in the reaction path where some bonds from the starting material are breaking and other bonds from the product are being formed) can normally not be observed, since it is so instantaneous, but Zewail gave us a peek behind that curtain.