Ocean Currents
With this experiment, you can study ocean currents in the safety of your own
home-no submarine required.
Materials:
Food coloring
Ice cube tray
Black pepper
Add 20 drops of food coloring to a large pitcher of water. Fill the ice cube tray with the colored water and put the trays in the freezer.
When the ice cubes are frozen, fill the wide-mouthed jar half way with warm water. Sprinkle some pepper in the water. The pepper will sink to the bottom.
Put TWO colored ice cube in each jar.
What happens to the pepper? Why does it do that?
The ice cubes are like huge polar icebergs, which melt in warmer water. As the
melting, icy-cold water sinks, the warmer water below gets squeezed up, bringing a current
of pepper up from the bottom.
This experiment demonstrates how differences in temperature between the surface and the
bottom of the ocean cause ocean currents. When the surface of the ocean cools to a
temperature lower than the water below, the cooler ocean water sinks, bringing up the
warmer water underneath it. Often this warmer water contains nutrients for plankton and
fish at the surface.
Nye Labs, http://nyelabs.kcts.org/homedemos/demo04.html