Hero’s Fountain

Hero’s Fountain has been around for a long time (circa 62 A.D.). Hero of Alexandria described a water fountain that used compressed air to lift water to a point higher than its origin. At first glance it seems the fountain requires no energy to run.
It actually runs on the potential energy in the water in bottle A relative to bottle B. As water flows throughout the system of tubing, the pressure in bottle B, and in turn in bottle A, increases and water is forced out the thin glass tube in bottle A. See Figure 1.