Marine Science in the 8th grade classroom

In Mr. Quien's eighth grade science class, students are modeling how temperature differences can cause ocean currents.  The colder blue colored water is moving across the bottom tube towards the warmer, red colored water, while the red colored water moves in the opposite direction completing a convection loop.

In this model, the blue colored water has salt added to it, and its higher density causes it to push across the bottom tube towards the less dense red, fresh water.  Students observe that not only temperature differences drive ocean currents, but differences in salinity also drive the ocean currents.