The water wheel is a mechanical analogue of the Lorenz equations, invented by Willem Malkus and Lou Howard at MIT in the 1970s. The basic idea is to create a wheel with leaky cups. Water is poured into the system and causes it to rotate (once there is enough water to overcome the friction keeping the system at rest). The wheel spins and depending on the flow rate of the water into the system, can spin and rotate chaotically, as in the video below. The first video is a waterwheel made by HMC students Jacob Wintersmith, Karen Shakespear, Mele Sato and Stephanie Moyerman in Math 181, Dynamical Systems.
Here is another HMC waterwheel made by Austin Rutledge and Katie Elisio. The experiments were done by CGU students Michael Davis, Leandro Recova, and Kristy Tran.