 | Project title: What Affects an Ocean Current? |
Difficulty level: | Middle school |
Main link: | None |
Hypothesis:
The purpose of this project is to understand how salt and water temperature affect water density, and how water density affects ocean currents. One may predict that when you have water of two different densities meeting, the lower density (less dense) water will move on top of the higher density (more dense) water, creating a density current.
Materials:
•clear tap water
•tap water with red food coloring
•tap water with blue food coloring
•slightly salty water dyed with red food coloring (5tsp salt)
•very salty water dyed with blue food coloring (14tsp salt)
•stirring rod/spoon
The Procedure:
-Part A: The Effect of Temperature on Wave Circulation-
1)Fill the container with 1.5 cups of really hot tap water. (If a hot plate is available use that) Add enough blue food coloring so that the water is just tinted light blue.
2)In a separate container, add half a cup of really cold tap water. Add red and green food coloring to make the water dark brown.
3)Using a spoon as a buffer, slowly pour an ounce of the really cold brown water into the experiment container prepared in step one.
-Part B: The Effect of Salt Content/Density on Wave Circulation-
1)Fill the container with 2 cups of tap water.
2)Create the very salty mixture by mixing a cup of tap water with 14tsp. of salt. Add enough blue food coloring to make the water dark.
3)Slowly pour 3oz. of the very salty (blue) water to the experiment container from step 1.
4)Create the slightly salty mixture by mixing a cup of tap water with 5tsp. of salt. Add enough red food coloring to make the water dark.
5)Using a spoon as a buffer, slowly pour 3oz. of mildly salty (red) water to the experiment container from step 1
6)Finally pour 3oz. of regular tap water (with green food coloring) to the experiment container from step 1.
Results:
•Part A: Colder water sinks below warmer water. Warm water (blue) tends lie as a layer on top of cooler water (brown).
-Temperature of the water causes deep ocean currents to travel back and forth between Polar Regions and the equator. The cold dense water sinks and travels to the equator, while warm less dense water rises and goes back to the Poles. There the water is chilled and again heads to the equator.
•Part B: Water with high salinity sinks below water with less salinity, and it will flow across the bottom of the container.
-When looking at the container from the side, the blue water should be on the bottom since it is the most dense; the red water should be on top of the blue water since it is less dense than the blue water; and the green water should be on top of the red water since it is the least dense of the three.