Ocean Circulation Learning Cycle - University of North Carolina

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Ocean Circulation Learning Cycle
By Lauren Fowler
ENGAGEMENT
Ocean waters are constantly on the move. How they move influences climate and living
conditions for plants and animals, even on land. Currents flow in complex patterns affected by wind, the
water’s salinity and heat content, bottom topography, and the earth’s rotation.
Using the Oceanview data display tool, or the Internet, teacher displays several maps of sea-surface
temperature, ocean salinity, and ocean circulation. Raise questions/elicit responses about these maps,
identifying students’ prior knowledge/misconceptions about these topics.
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Probe students for patterns in global
sea-surface temperature.
What is causing the temperature
regions seen here?
Have students hypothesize what
happens to ocean water as the
temperature increases.
Discuss the properties of seawater
(heat capacity, salinity, density, etc)
http://www.ssec.wisc.edu/data/sst/latest_sst.gif
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Question students about the ways in
which salinity levels change as
latitude increases.
Why is salinity so much higher in
the subtropical latitudes than it is in
the tropics?
Are these patterns consistent across
the entire planet? What might
change the salinity of a given area?
EXPLORATION
Students should now be given the opportunity to explore some of these ideas using the
Oceanview data display tool. The teacher should act as a facilitator, helping students to frame questions
by asking questions and observing. This is the opportunity for students to test predictions and
hypotheses, and/or to form new ones. The following is a list of suggested questions and buoys that may
or may not lead the students to finding the answers. The beauty of science is that there may not always
be a correct answer, so if the students do not find their expected answers by comparing two buoys, ask
them why! What kind of situations may need to be factored into the collection of the buoy data?
(weather events, human disturbance, etc) Have the students try graphing different dates for the buoys in
question to see if their results differ.
Select the Atlantic (Tropics) buoy and the North Carolina Coast buoy. Select salinity as the parameter.
1. Which area has warmer surface water temperatures?
2. Which area has higher salinity?
3. Are these the results that you would have expected? Why or why not?
4. Do you get the same results in January as you do in June? What about November?
 Now compare the North Carolina Coast buoy to the Labrador buoy. Select salinity and temperature
as the parameters.
1. Which area has warmer surface water temperatures? Is this what you would expect?
2. Which area has higher salinity levels?
3. Why is there such a drastic difference in salinity for these two areas?
4. Is it like that all year round?
5. What would you predict the dissolved oxygen to be like for these two areas?
6. Were your predictions correct?
 Compare the North Carolina Coast buoy to the Portugal buoy. Compare each of the parameters for
the two buoys.
1. Are these two buoys located at similar latitudes?
2. Would you predict that they would have similar temperatures throughout the year or will
they be different? Test your hypothesis by selecting temperature as the parameter and
various months of the year.
3. Were your predictions correct? Why or why not?
4. Now do the same for salinity and dissolved oxygen. Were your predictions correct?
Why or why not?
 Select the Labrador buoy and the Ireland buoy. Select temperature and salinity as the parameters.
1. Are these two buoys located at the same latitude? If not what is the difference?
2. Would you expect that they would have similar surface water temperatures? Why or why
not?
3. Scroll through the various months of the year to see if the temperature and salinity
patterns are consistent.
4. Any ideas why there is such a drastic difference in water temperature and salinity if these
two buoys are located so close to one another?
 Continue to compare buoys in the Atlantic Ocean, probing students with similar questions. See if
they begin to pick up on patterns/trends in the data. Extend the questioning to include any other topics
that you may want to include in your lesson.
EXPLANATION
Students should now be involved in an analysis of their exploration. Encourage the
students to explain concepts in their own words, asking for evidence and clarification of their
explanation. Students should use observations and recordings in their explanations. At this
point, you should provide definitions and explanations using students’ previous experiences as a
basis for this discussion. Perhaps, to start the discussion, you can ask if any of the students have
been out to the Gulf Stream off of the North Carolina coast. If so, have any of them noticed a
difference in water temperature or air temperature? The following are some suggested topics
that you may want to define/explain:
- Properties of sea water: average salinity, temperature/density relationships,
salinity/density relationships
- Hydrologic cycle: specifically, precipitation and evaporation, and their global effects on
seawater.
- Water displacement/ global wind belts
- Coriolis effect
- Global sea temperatures
- Warm water/ Cold water currents
EXTENSION
Students should apply concepts and skills in new (but similar) situations and us formal
labels and definitions. Remind students of alternative explanations and to consider existing data
and evidence as they explore new situations.
 Provide students with a blank map of the earth and colored pencils.
 Using the Oceanview data display tool have the students select various buoys in the northern
Atlantic and graph their data to determine the circulation of the North Atlantic Gyre
 Have them use red colored pencils to represent/draw warm currents and blue colored pencils
to represent/draw cold currents and draw their projected currents on the map.
 Go over the correct ocean circulation pattern with them and label any of the names of the
currents that you would like for them to know.
 Lead them in a discussion of other global ocean currents, predicting which way the water
flows and its temperature. Have students complete their map based on your discussion. You
may want to do this with them with the aid of an overhead projector.
 The students can then check the accuracy of their work against the ocean circulation map
provided by Oceanview, by selecting the ‘show circulation’ button.
http://www.geog.ouc.bc.ca/physgeog/contents/8q_1.html
EVALUATION
Evaluation can and should take place throughout the learning experience. You should
observe students’ knowledge and/or skills, application of new concepts and a change in thinking.
An optional evaluation activity would be to apply their new knowledge to solving a problem that
involves similar concepts, but also incorporates a more abstract thinking process. This will help
you to quantify the students’ understanding, and to determine weather the concepts need more
reinforcement. If you intend to teach about the effects of ocean circulation on global climate,
then the following activity could potentially lead into the start of a new learning cycle:
Same time, Same Place, Different Climate
Wilmington, NC and Los Angeles, CA are both located at approximately 340 N latitude. Do you
think that we have the same climate here on the east coast as they do over on the west coast?
How can you find the data that will answer this question?
Students can go to www.weather.com and select the monthly climate data for the two cities.
Help them to notice patterns in rainfall data, particularly during the summer months for the two
cities. In the interest of time you may want to have these data already printed out for them to
use.
Using the climate data, probe the students for answers to the following questions (either orally
in a discussion, or have them answer questions on paper)
 Which city has warmer summers?
 Which city has colder winters
 Which city receives more precipitation annually?
 What is the difference in average precipitation between the two cities during the
summer months?
 ANY IDEAS WHY?????
Using the Oceanview data display tool, compare the data for the buoy off of the North
Carolina coast with the buoy off of the California coast. Select salinity as the parameter.
 Which coast experiences warmer water temperatures during the summer months?
 What is the difference in temperature?
 Why do you think these two cities that are at the same latitude are experiencing
such a difference in ocean water temperature?
Change the parameter to salinity. Ask the students the following questions:
 What happens to the salinity of ocean water as the temperature increases? Why?
 What is causing this change in salinity?
 Does the data from the two buoys support your hypothesis? Why or why not?
 Which coast experiences higher salinity?
 Have the students select temperature and salinity as the parameters for their graphs. Also,
have them graph the data for June, July, and August. They should then compare their climate
data during these months to their ocean data.
 What effect does warmer ocean water have on the hydrologic cycle?
 Does warmer or colder water lead to more evaporation?
 Which city experiences more summer rainfall? Does this city have warmer or
colder water temperatures during the summer?
 What conclusions can you draw from comparing these data?
The following link provides a similar activity comparing ocean currents to climate:
http://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/oceanography_currents_4.html
This may be helpful in reinforcing the concept after the exploration and evaluation.
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