ConcepTest: Hot/Cold Water Circulation

A fish tank is filled almost to the brim with room temperature water. Two containers of cold and hot water are prepared. Red coloring is added to the hot water, blue coloring is added to the cold water. The cold water is added to the right-hand side of the tank as the hot water is added at the same time at the left side of the tank (see diagram). Circulation of the hot and cold water in the tank will share similarities with patterns of circulation in the ocean. Use the diagrams below to predict the paths the hot and cold water would take in the tank.

If you would like to help acquire more Before and After statistics for this example, please contact the authors (see link at top of page).