Set up the materials and wait at least 5 minutes to allow for the temperature differences of the water at each end of the container.

Add 3-4 medicine droppers of the colored hot water (red) to the heated end, letting the food color slide down the side of the container. Then watch what happens and record/draw, along with timing. (see photo at left)

Add 3-4 medicine droppers of the colored cold water (blue) to the icy end, letting the food color slide down the side of the container. Then watch what happens and record/draw, along with timing. Finally, sprinkle a small amount of baby powder on top. Watch what happens and record/draw along with timing.

Teachers found that:

• the colored water added to the warm end rose to the surface and spread across the surface until it reached the end of the container where it cooled down and began to sink. This created a vertical convection cell.

• the colored water added to the cold end sank quickly and showed little dispersal.

• the baby powder sprinkled on the top of the water illustrated that there was an additional convection cell established moving horizontally at the surface of the water initiated at the warmer end of the container