This exhibit was first developed by the Exploratorium. It shows an example of feedback. The metal ball falls slightly, the optic sensor drives more electricity to the magnet. Then the opposite happens and the ball appears to hover in mid air since the feedback loop is so fast. Unlike the original, our version allows the visitor to control the speed of the feedback loop to the point where it is too slow and the system fails. They can also listen to the frequency of the feedback loop as they change it.