Currents from a Cup

Engage

15 Minutes

Revisit and make entries in the ladder of learning.
Then, pose the question: How do polar and tropical climates affect ocean currents? Give students 3-5 minutes to write their hypotheses, and then have them share with the class.

Make sure students are giving cause and affect.
Use sentence stems like:
If I (independent variable) _________, then ________ will happen (dependent variable).
Or
I think that (independent) _________ because (dependent) __________.

Explore

35 Minutes

Students in groups of 2-4 will do another experiment that demonstrates temperature currents, following the directions.  After coming up with a hypothesis, they will set up and observe a simulation of currents by releasing hot and cold water slowly into a tub or aquarium.

If equipment is available, give students the opportunity to use video or photos to record their observations.

Explain

20 Minutes

Ask students to share what they have learned and record their findings in a class list. Share and discuss any new questions that have arisen.

The following is a list of possible observations:

1. Cold water sinks and warm water floats.
2. Currents get established due to the difference in density between hot and cold water.
3. When hot water cools, it sinks.
4. When cold water warms, it rises.
5. Currents shut down when the temperatures become equal.
6. Water cools in polar climates and warms in the tropics.

After debriefing ask student groups to answer the following questions. Some resources from your library or the Internet will be helpful in answering these questions:

1. Where on the surface of the earth does water get heated? Cooled?
2. Mark these locations on the map from Investigation 1. Arctic, Antarctic, Equatorial. How do temperature differences cause ocean currents?
3. Ask students if they think habitats could change if water temperatures became more uniform.
4. What is a thermocline?

Ask students if there are any questions. If so, encourage classmates to answer. If time and interest permits, discuss the upwelling of nutrients and the effects on habitat.

Elaborate

20 Minutes

Have students draw a color technical drawing that includes explanations for why temperature currents establish and diminish in the ocean.

Evaluate

Have students write a conclusion to assess what they have learned. A well organized claims and evidence table will lead to a great conclusion.

Claims/Inferences (what you believe to be true)    Evidence/Data (should support your claims)
    
Students should address their hypotheses, right or wrong, things they may have had troubles with or what they think would have made their experiment go better. They should also address any questions or new hypotheses that they may have had.