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Current Interactions

Inspired by: http://www.lessonplanspage.com/ScienceOceanCurrents78.htm
Adapted by: Kirstin A. Bittel


Time:
3 periods
Preparation Time:
10-15 minutes making copies
Materials:
Overhead of World Ocean Current Map
Overhead of Subsurface Ocean currents
Beach sand
Baking Dishes
Fans or hair dryers
Ice cubes
Cold Water
Tap water
Hot Water
Rulers
Clear baking dishes (one per group)
Straws
Beakers – 6 per group
Salt
Water
Food coloring – 5 colors (to differentiate salinity)
Scale to measure salt

Abstract
Students will design a simulation to explore how water, heat, and salinity affect the flow of the world’s ocean currents. They will present their results to the class.

Purpose – Exploration of the many factors that affect the flow of the world’s ocean currents.

Objectives
Students will be able to:
1. Design an experiment to see how wind, temperature, and salinity work together to influence ocean currents and present it in a report format.
2. Explain to their classmates how experiment findings relate to ocean currents.

National Science Education Standard:
CONTENT STANDARD D: Earth and Space Science
ENERGY IN THE EARTH SYSTEM

• Earth systems have internal and external sources of energy, both of which create heat. The sun is the major external source of energy. Two primary sources of internal energy are the decay of radioactive isotopes and the gravitational energy from the earth’s original formation.

• Heating of earth’s surface and atmosphere by the sun drives convection within the atmosphere and oceans, producing winds and ocean currents.

• Global climate is determined by energy transfer from the sun at and near the earth’s surface. This energy transfer is influenced by dynamic processes such as cloud cover and the earth’s rotation, and static conditions such as the position of mountain ranges and oceans.

GEOCHEMICAL CYCLES

• Movement of matter between reservoirs is driven by the earth’s internal and external sources of energy. These movements are often accompanied by a change in the physical and chemical properties of the matter. Carbon, for example, occurs in carbonate rocks such as limestone, in the atmosphere as carbon dioxide gas, in water as dissolved carbon dioxide, and in all organisms as complex molecules that control the chemistry of life.

Teacher Background
The world’s ocean currents are driven by many forces. The water in the upper ocean is driven primarily by the wind. Deep ocean currents are driven by salinity and temperature (both of which affect density). The salinity of water is related to the geologic formations in an area. Salinity tends to be lower near igneous formations and higher near sedimentary formations.

Surface currents tend to move relatively quickly (warm waters more so than cold waters), while subsurface currents flow more slowly.


Related and Resource Websites
Ocean World - Currents
http://oceanworld.tamu.edu/students/currents/index.html
Surface and Subsurface Ocean Currents
http://www.physicalgeography.net/fundamentals/8q.html
Ocean Current Temperatures
http://geography.about.com/library/misc/blcurrents.htm

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Activity
1. Tell students that over the last three days they investigated the effects of three different variables on ocean currents. Those variables are involved in both the surface and subsurface ocean currents.

2. Show students the overhead so they can see where the surface and subsurface currents flow.

3. Tell students that today they will be responsible for setting up their own experiment to see how the three variables work together to influence currents.

4. Remind students that in an experiment there is an effort to identify all the variables and control them so that only one variable is changed at a time. This allows the investigator to examine the input of that one variable within the system. Students should also be encouraged to incorporate multiple trials to ensure that the results they are seeing are reproducible.

5. Some questions students should consider are: Which has a greater affect on water- density, temperature or salinity? What causes the upwelling or downwelling of water? In those regions of the ocean that you would suspect higher concentrations of salinity, how will water temperature change the ocean currents?

6. Divide the class into groups and send them to their laboratory stations. Ask them to devise a plan for their investigation. What do they want to test? What are the variables in the system? Which variables will they change and which will they hold as constants? Students should identify these as dependent and independent variables.

7. Allow students 1-2 class periods to conduct their experiments. They may conduct several as long as each experiment has only one variable and the experiment is replicated at least three times before moving on. Advise students that on the third day they will be asked to prepare a brief presentation sharing their research question, methods, results, and finally, discuss the implications of their findings on ocean currents.

8. On the final day, students should share their results with the class and submit a report to the teacher.


Closure
How do student findings relate to ocean currents?

Embedded Assessment
Through their laboratory report and the class presentation, students can be assessed on the following questions:

Can students plan an experiment that tests only one variable at a time?
Do students conduct multiple trials?
Can students draw valid conclusions?
Can students discuss the implications of their findings as they relate to ocean currents?

 


PULSE is a project of the Community Outreach and Education Program of the Southwest Environmental Health Sciences Center and is funded by:


an
NIH/NCRR award #16260-01A1
The Community Outreach and Education Program is part of the Southwest Environmental Health Sciences Center: an NIEHS Award

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LOGO - NIEHS Center LOGO - NIEHS

Supported by NIEHS grant # ES06694


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Last update: November 10, 2009
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