GRADE: Fourth

CONTENT STANDARDS: Earth and Space Science

CONTENT TOPIC: Oceanography

CONCEPT: Oceans are important to life on earth.

CONTENT OBJECTIVE: 4M4.00 To understand the movement of oceans in currents, tides, and waves

INSTRUCTIONAL OBJECTIVES: The learner will:

4.01 trace the pattern of ocean currents.

I. Ocean currents
II. Kinds of currents
III. Northern hemisphere and southern hemisphere currents
IV. Salt water is heavier than fresh water.
V. Trade winds are easterlies and westerlies
VI. Tsunamis are giant waves

TN COMPONENT OF SCIENCE: Unifying Concepts of Science

TN GOAL:

To enable students to acquire scientific knowledge by applying concepts, theories, principles and laws from life/environmental, physical, and earth/space science.

2.1 SCALE AND MODEL - The development of models provides a conceptual bridge between the concrete and the abstract, while the use of scales allows for a comparison of differences in magnitude between the model and the desired form.

2.1b Different models can be used to represent the same thing. The kind of model used and its complexity depends on the purpose.

BENCHMARK: Models allow us to make inferences about real world processes and events.

TIME REQUIRED:

Two to three instructional periods

World map, globe, newspapers from large coastal cities, work sheets, poster board, glass bottles, salt, food coloring, card

(Show students a map of the Atlantic Ocean.) Benjamin Franklin became curious because ships could go from America to England faster than they could go from England to America. (Trace this journey on the map. Have students tell their neighbor possible explanations for this.) Today we are going to learn about the ocean currents.

(Have globe and/or world maps available. If possible, have access to newspapers from major coastal cities.) Some ocean facts are:
1. Currents are large moving rivers of water in the ocean. These movements of ocean water are in a particular direction.

2. Oceans are in continual motion due to the spinning of the earth, the gravitational attraction of the moon, surface winds, and heating by the sun.

3. Ocean currents occur on and below the ocean surface. Ocean currents on the surface are basically caused by winds. Deep ocean currents are caused by the uneven heating of ocean water by the sun. Activity:

Fill a clear plastic container 3/4 full of tap water. Place a rock in a bag that is 1/2 full of hot water and tie the bag closed. Place bag in one corner of the box. Float an ice cube in the opposite corner. Add 4 drops of food coloring to the water next to the ice cube. Observe for five minutes.

4. Uneven heating of ocean water also causes some areas to have a higher salt content, causing a circular current.

5. There are three different kinds of currents, depending on their origin.

a. Density currents - caused by differences in temperature and salinity of nearby water
b. Wind currents - caused by motion of prevailing winds
c. Tidal currents - produced by the ebb and flow of tides

6. North hemisphere currents move toward the right. Southern hemisphere currents move to the left.

7. Saltier water is heavy and sinks. Less salty water moves over it. When salty water meets less salty water, a current is formed. (To illustrate the movement of water with low salt content to high salt content. Fill one glass bottle with salt water, add blue food coloring. Fill an identical bottle with tap water. Place a card over the mouth of the bottle of salt water. Carefully invert the bottle and place it over the mouth of the bottle of tap water. Remove the card very carefully. The blue salt water will sink, because it is heavier than the tap water. The tap water will move up over the saltier water.)

8. Cold water currents carry cold water away from the North Pole and the South Pole. Most of east coast is affected by warm water currents, and most of west coast is affected by cold water currents.

9. Define trade winds - winds that blow from east to west toward the equator are called easterlies. Westerlies blow from west to east, away from the equator.

10. Ocean movements are classified as current, tidal and wave.

11 Waves are caused by the rising and falling of ocean water. (a slinky my be used to demonstrate wave motion. OR Fill a pan with water. Float a cork on the water. Stir the water in the center of the pan to form waves. Observe the cork motion. Bottle waves can be made by combining water, oil and food coloring.) Giant waves called Tsunamis are caused by earthquakes or other movements of the ocean floor such as volcanoes or landslides.

1. Assign groups of students an ocean to study and research. Each group should create a poster with pictures and information about its ocean.

2. Find names of major surface currents and where they are located. Students will point these out on the globe or map showing warm and cold water currents.

3. If newspapers from major coastal cities are available, use these for group work. Report on damage caused by tsunami winds in the past. Locate and graph the tide tables for several days. Compare, then check again at regular intervals.)

Whisper to your neighbor one word that means movement of water in a particular direction. (Current) Write a paragraph explaining the difference between swimming in a lake and an ocean.

(Distribute blank maps of the world. Have students use colored pencils to indicate major ocean currents. Use red pencil for a warm current and blue pencil for cold current.

(Have students "or groups" write to an Oceanography Institute, requesting information about oceanography. A good one is Education Office, Woods Hole Oceanographic Institute, Woods Hole, Massachusetts, 02543.)

This is the time this file has been accessed since 07/01/97.

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