Goals:

1. Label the names, relative temperature, distribution, and direction of flow of major ocean currents on a world map.
2. Explore and model the natural forces that affect the movement of ocean currents through demonstrations in class, laboratory experiments, and internet research.
3. Research and summarize how ocean currents affect society, particularly in areas of nutrient rich upwelling.
4. Document ocean current lab activities and observations and document internet research in a lab write up .
5. Solve mathematical problems related to hypothetical journeys by Timothy and Philip (The  Cayand Timothy of the  Cay ) which involve distance, rate, and time.
6. Research the internet to observe seasonal variations of ocean currents, water temperature, ocean water salinity, and wind speeds.

Resources:

1. Portions of this lab were modified from Lab 35: Ocean Currents of  the following resource:
   Alexander, Peter, et. al., Earth Science Laboratory Manual, Teachers Edition.  Morristown. Silver Burdett Company, 1987
2. The following internet site:  http://metosrv2.umd.edu/~owen/EARTHCAST/BUTTONS21/buttons21.html

Materials:

Part II - Surface Ocean Currents
1. Multiple copies (one for each student) of world maps showing the major unlabeled surface ocean currents
2. Each lab group should have the following:
   1 circular pan (at least 10 in diameter)
   1 lazy Susan
   food coloring
   1 medicine dropper
   water
   1 small fan
   modeling clay
    

Part III - Deep Ocean Currents

1. Each lab group should be supplied with the following:
   1 clear rectangular pan (9 x 13 or larger)
   1 wooden or metal partition to divide the rectangular pan in half the short way
   modeling clay
   food coloring
   hot tap water
   ice
    

Part IV - Mathematical Computations

1. Each student should have the following:
   calculator
   ocean current maps (created in earlier part of lesson)
   rulers
   string

Time:

This lesson will take approximately 8 hours (Parts I and II: 4 hours, Part III: 3 hours, Part IV: 1 hour)

Procedure:

Part I.  Introduction (by the teacher to the class)
1. Describe and illustrate to the class the two types of ocean currents (surface and deep ocean currents) and give general characteristics of each. Example:
   Surface Ocean Currents - are shallow (<100m) and relatively fast moving
   Deep Ocean Currents - are several kilometers deep and relatively slow moving

   Note:  There need not be much detail here, as the students will learn the details in the remaining portion of the lesson. Diagrams would be very helpful in the introduction.
    

Part II.  Shallow Ocean Currents

1. Show the students a map of the world (large map, overhead projection, etc.) which illustrates the major surface ocean currents. While the students look at the map:
   a) Ask them to pick out any patterns that are evident with respect to the direction of flow. (Students should be able to see, either on their own or with some assistance, that the currents in the Northern Hemisphere are circulating clockwise and that the currents are moving counterclockwise in the Southern Hemisphere)
   b)  Ask the students what natural forces might contribute to the different directions of movement of these surface ocean currents. (Answers may vary and may be quite creative, but the two major natural forces in action are wind and the rotation of the earth).
2. Describe and illustrate (using chalkboard, overhead projection, etc.) how wind and the rotation of the Earth contribute to the different current directions.  This is a good time to describe the Coriolis Effect, which is the scientific term that describes how the rotation of the earth controls the circular direction of wind and water currents.  A  motivational demonstration that could be done is to show students how the water goes down a drain or toilet clockwise or counter-clockwise, depending what hemisphere the students live in.
3. Give each student a copy of the world map with the following unlabeled surface ocean currents drawn on:
   Antarctic Current (West Wind Drift)
   South Equatorial Current
   North Equatorial Current
   Peru Current
   Brazil Current
   Benguela Current
   Equatorial Counter Current
   Japan Current
   Alaska Current
   California Current
   Gulf Stream
   North Atlantic Drift
   Labrador Current
   SW Monsoon Drift
   West Australian Current

   Note:  For a more challenging exercise, give the students a map without any of the ocean currents on and have them draw the currents on themselves as part of the following exercise.

4. Divide the students into pairs and instruct them to use classroom resources (texts, encyclopedias, internet, etc.) to locate the surface ocean currents, determine whether they are warm or cold water currents, and to label the map accordingly.  When the students complete this activity, discuss the correct answers in class.
5. Upon completion of the map labeling activity, inform the class that they will be using laboratory equipment and discuss any safety rules that must be followed.
6. Divide the class into groups of 2-3 and instruct each group to follow the directions below and to document every step performed and every observation made during the activity on the attached lab write-up sheet. (Note:  The students could use individual lab notebooks rather than providing them with a worksheet, as long as the teacher discusses what format is expected and what information is to be included in their notebooks)

   
   To demonstrate how the Coriolis Effect controls ocean current direction:

   a)  Fill the round pan with several centimeters of water and place the pan on the lazy Susan.  It may be helpful to tape the pans down to prevent them from later slipping off.
   b)  Gently rotate the lazy Susan clockwise.
   c)  Add a drop of food coloring near the rim of the pan and stop the lazy Susan from rotating.
   d)  Observe the movement of the food coloring and hypothesize what natural force this activity demonstrates.
   e)  Repeat the experiment, except turn the lazy Susan counter-clockwise instead and observe what happens.

   To demonstrate the affect a natural obstacle (island, land mass, etc.) has on an ocean current:

   f)  Place a fist size lump of modeling clay or a rock onto the bottom of the empty round pan.
   g)  Repeat the above experiment and describe what happens to the food coloring (ocean current) as it hits the obstacle.

   To demonstrate the affect that wind has on an ocean current:

   h) Direct a small fan toward the pan of water (blowing on the water works as well) and observe the water movement that   results.  A drop of food coloring may be added to see the effect of the fan (wind) more clearly.
7. Instruct the groups to visit the following internet site: http://metosrv2.umd.edu/~owen/EARTHCAST/BUTTONS21/buttons21.html
   a)   Instruct each group to look at the OCEAN CURRENTS category and have them observe the seasonal variations of surface ocean currents (January, April, July, and October).  Instruct them to record their observations in their lab write-ups.
   b)   Instruct each group to look at the WIND category and have them observe the monthly variations for 1995.  Have the students record the major differences in wind speeds from month to month that exist in the oceans at various locations.  Again, have them record their findings in their lab write-ups.

Part III.   Deep Ocean Currents

1. Describe and illustrate to the class how deep ocean currents form as a result of density differences in water.  The following examples describe this in more detail and demonstrate two ways that deep ocean currents form:
   a)   Cold water is more dense than warm water and therefore will sink to the bottom   of the ocean.  This results in the surface of the ocean being much warmer than the water at depth.
   b)   As water freezes into ice in arctic conditions, the water that does not freeze becomes much more saline (salt content increases).  Water that has a high salt content is more dense and as a result will sink.

   Explain that as the cold, dense water sinks, it pushes the water on the bottom of the ocean outward and upward.  Some of the cold water may mix with the warmer water and begin to rise toward the surface (warm water rises). Much of the cold water remains near the ocean floor for thousands of years. Another way that the cold bottom waters can reach the surface is through the process of upwelling.  Upwelling occurs in some coastal areas, and involves deep cold nutrient rich water rising to the surface as a result of strong coastal winds pushing the warmer surface water away from the coast.  The water is full of nutrients and can support many organisms which feed on the nutrients.  Most of the great fishing areas of the world are located where this upwelling occurs.

2. Assign the students to individually research and hypothesize the effect that the upwelling of nutrient rich waters near coastlines has on society.  They can do this by discovering the different kinds of organisms that flourish in these coastal upwellings. Instruct them to write a short essay on their findings.
3. Prepare the students for using the laboratory equipment by, once again, going over the safety rules that must be followed at all times.
4. Divide the class into groups of 2-3 and instruct them to follow the directions below and to document their work the same way they did in the first lab activity.

   
   To demonstrate how cold water is more dense and will sink beneath warm water:

   a)  Using the metal or wood partition and the modeling clay, build a water-tight  partition in the middle of the rectangular pan.
   b)  Fill one side of the pan with cold tap water and add ice to make sure it is very cold. Make sure the partition is water-tight  Place several drops of food coloring in this cold water and stir.
   c)   Fill the other side of  the pan with very hot tap water.
   d)   Very gently remove the partition and observe what happens.  (The cold, colored water will spread out on the bottom).
5. Instruct each group to visit the same internet site listed above:  http://metosrv2.umd.edu/~owen/EARTHCAST/BUTTONS21/buttons21.html
   a)  Have the students chose the TEMPERATURE category.  This category gives worldwide distribution maps of the ocean water temperature at different depths.  Instruct the students to observe and document (in the lab write-ups) the temperature of the ocean water on Earth, both at the surface and at different depths.
   b)  Upon completion of observing temperature differences, instruct the students to chose the SALINITY category.  This category displays the worldwide distribution of differing salinity characteristics and shows how they change with depth.  Instruct the students to document their observations in their lab write-up sheets.

 

Part IV - Mathematical Computations

1. Instruct the students to imagine that Timothy and Philip build a raft and set off for sea from the island they are stranded on.  Assuming that the only means of moving the raft is by ocean currents (no winds, waves, etc. ), instruct the students to determine where the two will end up and how long it will take them to get there.

   
   The students will need to determine the following:

   the geographic location of the island
   which ocean current(s) will be the primary carrier(s)
   how fast the ocean current(s) move on average
   where the ocean current(s) reach land
   how far away this destination is from their starting point, the island

   Essentially, from anywhere in the Caribbean, Timothy and Philip would most likely get moved by the Gulf Stream and end up in Great Britain or its neighboring countries.

   Note:  this is a distance, rate, and time mathematical problem, and the students may need some instruction about how to solve such problems prior to completing this activity

2. Repeat this exercise (as many times the teacher feels is necessary for the students to have a good grasp on this type of problem), but have the starting points be from different areas around the globe.
3. Because this exercise required the unrealistic assumption that nothing will be moving the raft except the ocean currents,  prompt a class discussion on some other factors that might effect the way the raft travels (ex. wind, hurricanes, storms, waves, etc.).   Because many of these factors would have negative impacts on humans traveling on a raft at sea, this may open the door to a discussion on general survival at sea and the students could discuss preparations that Timothy and Philip would have to make prior to such a journey.

Assessment:

1. Students hand in world maps with labeled ocean currents.  (Criteria for success = neat, accurately labeled maps showing locations of major ocean currents and depicting whether the particular ocean currents are warm or cold)
2. Observation of studentsí participation in class-room discussions, laboratory activities,  internet research, and group activities. (Criteria for success = students are actively engaged, work cooperatively with one another and with the teacher.  See attached Rubric A)
3. Students hand in summaries on the effects of upwelling on society.  (Criteria for success = summaries are well written, contain accurate information, and display a clear understanding of  the effects of upwelling.  See attached Rubric B)
4. Students hand in lab write-ups that document lab activities and internet research.  (Criteria for success =  lab write-ups are well written, neat, contain accurate information, and display a clear understanding of lab activities and internet research.  See attached Rubric C)
5. Students hand in mathematical calculations.  (Criteria for success = mathematical problems demonstrate that the students understand the correct procedure to use, students are able to use complex reasoning skills effectively, and students are able to interpret and synthesize information effectively.   See attached Rubric D)

 
1. Language Arts - writing assignments associated with labs and research, group activities
2. Science - ocean currents and lab activities
3. Social Studies - research on how upwellings affect society
4. Mathematics - problem solving, measurements

Possible Extensions:

1. Research the El Nino, which is a particular warm water ocean current in the Pacific Ocean. Students will find a lot of information on the internet about this current.
2. Calculate how long it would take to travel via ship from the United States to Europe and from Europe to the United States.  By using different rates due to either traveling with or against the ocean currents, the answers should be variable.

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Caribbean Cruisers - developed by Sara Bork, Carrie Kriescher, Candice Murphy, & Melissa Randall

This page submitted by St. Norbert College Ocean Voyager Program