Convection Currents employs a water tank, heater, and light source to project images of convection currents. The visitor can control the heater and the projector. In effect, chaotic streams of warm and cool water sculpt lenses of ever-changing shapes. Water, like air, expands as it warms, which makes it less dense than cooler water. As the heated water threads its way through the cooler water, the friction of water rubbing on water and on the glass sides causes turbulence. Turbulence is chaotic behavior and the swirling patterns change unpredictably.