J11.01.42 Maxwell's Wheel. This classic device is used to demonstrate the conservation of mechanical energy. When the wheel is rotated by hand to the top and released, its potential energy will turn into kinetic energy (rotation) as it falls. After the wheel reaches its bottom position, the kinetic energy will change back to potential energy when it moves up again. This process will continue on until the total energy is lost due to friction. All metal construction. 18x2x5" 5.6lb. Instruction manual included.