The gap between two panes of glass is filled with water.
Light is projected through the glass while the bottom surface is heated.
The motion of fluids is seen in the density currents. Relate air currents to density currents in the ocean due to temperature differences in the water. Relate this also to turbidity currents due to density changes. Turbidity currents are highly turbid, relatively dense ocean currents carrying large amounts of clay, silt, and sand in suspension. The current flows down a submarine slope through less dense seawater.