Physical Dynamics of the Ocean

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 2

Analyze the physical and biological dynamics of the oceans.

Indicator b

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

Indicator b

Determine how physical properties of oceans affect organisms (e.g., salinity, depth, tides, temperature).

Intended Learning Outcomes:

  1. Use Science Process and Thinking Skills
    1. Observe objects, events and patterns and record both qualitative and quantitative information.
    2. Evaluate, sort, and sequence data according to given criteria.
    3. Plan and conduct experiments in which students may:
      • Identify a problem.
      • Formulate research questions and hypotheses.
      • Predict results of investigations based upon prior data.
      • Select the appropriate format (e.g., graph, chart, diagram) and use it to summarize the data obtained.
      • Analyze data, check it for accuracy and construct reasonable conclusions.
      • Prepare written and oral reports of investigations.
  2. Demonstrate Understanding of Science Concepts, Principles and Systems
    1. Know and explain science information specified for the subject being studied.
  1. Communicate Effectively Using Science Language and Reasoning
    1. Provide relevant data to support their inferences and conclusions.

Description of Activity:

TITLE - PHYSICAL DYNAMICS OF THE OCEAN

Overview
This activity could be used to introduce the section on ocean dynamics and its physical properties. It is an inquiry designed to promote experimental design.

Duration of Activity - One class period

Materials:

  • Wide mouth glass jars
  • Red food coloring
  • Blue food coloring
  • Pepper grains
  • Warm water
  • Cold water
  • Frozen colored ice cubes
  • Small bottles with caps
  • Glass tanks or large bowls
  • Unboiled eggs
  • Table salt

note: This lab can be done in a standard classroom with tables.


Background Information:

The students should have a good background in experimental design. No prior knowledge is needed in ocean dynamics. This activity could also be used as a review or test after the unit has been discussed in class.

Teaching and Learning Strategies:

Ensure inquiry
To ensure a level three inquiry the students need to develop their own hypothesis, plan their procedure, and draw their own conclusions. Do not feel the need to answer all their questions, let the students discover the answers themselves. Try to answer questions with questions. Do not discuss with the students currents, or the relationships between density, salinity, and temperature prior to this activity.

Prerequisite instruction
Before beginning this activity, teach the process of experimental design. This activity will serve as practice.

Invitation to Learn:

Problem: What physical properties influence ocean dynamics?

Instructions
This large question will be explored by the students by breaking it into three more direct questions that they will explore as teams.
A. What are the differences in properties between fresh and saltwater?
B. What physical properties influence currents?
C. What environmental changes influence the mixing of ocean waters?

If students need a less complex or advanced approach to inquiry, use a discrepant event in place of the questions above. Examples are as follows:

  • You float eggs in two similar looking liquids, one floats, one sinks. Why?
  • A colored ice cube is placed in a container, you notice movement of particles on the bottom of the container and eventually colored water rises. Why?
  • A bottle of colored water is placed in a large tank of clear water, when the cap in unscrewed the colored water rises to the top. Why?
  1. The students are placed into teams of three or four (depending on class size and materials available). Ask each team to investigate a different problem associated with the physical properties that influence ocean dynamics. (There may be more than one team investigating each problem depending on class size.)
  2. Instruct the teams to formulate a hypothesis, and design an experiment to test the hypothesis. (See "Steps of Experimental Design" below.)
  3. Allow students time to conduct the experiment and draw conclusions about the relationships they discovered and the properties they observed.
  4. Have the supplies listed above available for student use. Tell the students that they are welcome to use any of the materials supplied.
  5. Ask the students to communicate the results. (See "Strategies and tools to share findings" below).

Summary of Learning:

Assessment
Multiple choice questions
1. The relationship between density, salinity and temperature in saltwater can best be described by which of the following statements?

A. The density decreases with a temperature decrease or a salinity decrease.
B. The density increases with a temperature increase or a salinity increase.
c. The density increases with a temperature decrease or a salinity increase.
D. The density decreases with a temperature increase or a salinity increase.
E. There is no proven relationship between the three factors.

2. Which steps in the experimental design are in proper sequence?

A. Observe, analyze results, hypothesis conclusion
B. Observe, hypothesis, experiment, conclusion
C. Hypothesis, observation, question, conclusion
D. Procedure, hypothesis, experiment, conclusion

Other assessment tools
Have the students as a team or as individuals complete the following rubric:

YES NO STEPS OF THE EXPERIMENTAL DESIGN


Problem clearly stated


Hypothesis (with answer to problem
and why that prediction was made)


Procedure to test hypothesis written out


Variables and control present


Materials used listed


Data sheet with data


Conclusion (answers problem and explains why)


Report of experiment (teacher determines)

Strategies and tools to share findings:

  1. Conduct a peer review. Have each group that explored the same problem exchange procedures and retest the experiment. Then have the two groups share their findings with each other and design a conclusion based on their results and analysis.
  2. Have each group prepare an oral presentation with visuals and handouts that explain the results of their experiment and teaches principles in ocean dynamics.
  3. Following oral group reports, have students write a response to the overlying questions of "What physical properties influence ocean dynamics?"

Extensions:

  1. Have students design experiments that would prove the conclusions they drew from their observations following the experimental design method.
  2. Introduce the following topics after the students conclude with their team projects:
    • Properties of seawater - Have the students freeze saltwater and tap water at the same time at home. Ask them to determine which freezes faster and why? How does this apply to the organisms that live in these waters?
    • What is the relationship between currents and temperature?
    • What is the relationship between vertical water movement and the feeding patterns of organisms?