Convection Cell “Sea Breeze“ Visualization

Convection cell demonstration narrated by Steven Wofsy for E-PSCI 338 February 2020. A heating element in the bottom-right side of a tank of water causes convective circulation. The warm water above the heater rises up to the surface and moves over to the left side of the tank, where it starts to cool. Losing buoyancy as it cools, the water gradually returns to the bottom, where it completes the cycle by being drawn back into contact with the heater. One can draw an analogy with this demo and onshore breezes that occur along the coast on hot summer days. In that case, air heated by land rises up and is replaced by cooler air moving in from over the ocean. The tank was custom built at Harvard Bio Labs Machine Shop in Cambridge, MA; it is about 14“ x 10“ x 2“ and is made out of acrylic. The heater is a 125W Cenco Knife Type Immersion Heater connected to a Variac. About 20 drops of concentrated rheoscopic fluid were added to distilled water.