Ocean Dynamics

Standard IV

Students will understand that water cycles through and between reservoirs in the hydrosphere and affects the other spheres of the Earth system.

Objective 02

Analyze the physical and biological dynamics of the oceans.

Indicator a

Describe the physical dynamics of the oceans (e.g., wave action, ocean currents, El Nino, tides).

Intended Learning Outcomes:

  1. Use Science Process and Thinking Skills
    1. Observe objects, events and patterns and record both qualitative and quantitative information.
    2. Use comparisons to help understand observations and phenomena.
    3. Construct models, simulations and metaphors to describe and explain natural phenomena.

Summary: Students will demonstrate how salinity and water temperature affect the ocean's currents

Materials:

  • Clear plastic tub, aquarium or other container (4-8L)
  • Four beakers (250 mL)
  • Table salt
  • Food coloring
  • W arm water
  • Cold water
  • Ice
  • Container to make an ice bath for a 250mL beaker

Sequence and duration: (one 30-45 min. class period)

I. Student Directions:

  1. Make a saturated salt solution by slowly adding salt to 400 mL of warm water (35-40 degrees Celsius) until no more salt will dissolve.
    **(The teacher may want to make a quantity of warm, saturated water. Each group needs 400mL.)
  2. Put 3-4 drops of food coloring in the salt water solution.
  3. Pour 200 mL of the salt solution into one beaker and 200mL into a 2nd beaker.
  4. Put one of the beakers in an ice bath.
  5. Prepare two beakers exactly as above but omit the salt.
  6. Use thermometers and adjust the water temperatures so that the beakers containing warm water are as close to the same as possible. Do the same with the beakers of cold water.
  7. Fill the clear plastic container with clear, cool water.
  8. Choose one of the beakers and gently pour its contents down the inside of the plastic container.
  9. Observe and record your observations.
  10. Empty the contents of the large, clear container.
  11. Repeat steps 8-10 for the three remaining beakers.
  12. Clean up all materials.
  13. Use your data to suggest a reason for the results you obtained.

II. After performing the experiment, the teacher should pull the class together to report on their activity results and form some general conclusions.

III. Students should then read Appendix A: "Circulation of the Oceans." As a class, discuss how the article relates to the activity.

Appendix A

NOTE: The reading may be challenging to some students. The teacher may need to guide student's reading to ensure comprehension.

Extension

Connect the movement of ocean currents to the carbon cycle.

PART 2 ( 20-30 min )
I. Have students read the student background information sheet.

As a class , discuss these questions after reading both articles:

  • How does the ocean absorb carbon dioxide?
  • What factors influence how much carbon dioxide the ocean absorbs?