Hero's fountain—a device with a surprising effect—was commonly found in physics collections until the early twentieth century.

To activate the mechanism, the upper globe must be filled with water and the lower globe must be empty. The water is poured slowly into the cup at the top. The water flows through a tube into the lower globe, compressing the air inside it. The air is expelled through a second tube into the upper globe. There, the air compresses the water, which escapes through a tube fitted with a nozzle and splashes back into the cup. The process continues until the lower globe is full.