Everything reacts differently to pressure, even fluids. Our simple device shows how a fluid changes behavior even under it's own weight. When our clear tube, containing 3 brass nipples positioned one on top of each other, is filled with water, the water shoots out at different rates of speed. The water at the bottom will have the most water above it, increasing the pressure and hence the rate of speed at which it spouts. The water pressure decreases proportionately for the two upper nipples. If the pressure is low, water won't escape at all. Unbreakable polycarbonate tube on stand, 3 brass nipples and instructions.