TEA Banner
TEA Navbar

The Shape of the Ice: Using Maps to Learn About Antarctic Topography

data | hook | main | background & resources | student

Author Contact Information

Rolf Tremblay, Goodman Middle School, Gig Harbor, Washington
tremblay@tea.rice.edu

Overview
Students explore maps to become familiar with features of Antarctica. They are introduced to a topographic map which is used to construct a three-dimensional model of the continent. Students employ these models to investigate the nature of Antarctic ice.

The student will:

  • examine and interpret different types of maps.
  • use a topographic map to create a 3-dimensional model.
  • identify and describe different regions of Antarctic ice.

    Grade Level/Discipline
    Grades 5-8/ Earth Science, Geography

    National Standards

  • 4B The Earth
  • 4C Processes that Shape the Earth
  • 11B Models

    Pre-activity set-up

  • Make copies and transparencies of maps.
  • Locate Antarctica resources (e.g. GLACIER Web site)

    Materials

  • Map of Antarctica two copies for each group of 2-4 students, transparency

  • The Ice Sheet Surface of Antarctica 1000 meter topographic map two copies for each group of 2-4 students, transparency

  • The Ice Sheet Surface of Antarctica 500 meter topographic map transparency

  • Antarctica: The Bedrock at Sea Level transparency

  • white tagboard, cardboard scraps, scissors, glue sticks or rubber cement

    Time Frame
    Two class periods

    Engagement and Exploration (Student Inquiry Activity)
    Divide the class into small groups of two to four students. Provide each group with copies of the Map of Antarctica. Ask each group to list things they can tell about Antarctica by looking at the map. Have them share and discuss their findings with the class. Next, have groups list things they can't tell about the continent from the map. Share and discuss the results.

    Explanation (Discussing)
    Students may have noted the lack of information about elevation or topography. If not, bring it to their attention. Introduce the term topography, which refers to the elevation and shape of the land.

    Pose the following questions to the class:

  • Can you tell the elevation of any place on the map? (Yes - The line representing the coast is at sea level.)

  • If someone were to walk along the path represented by that line, would their elevation ever change? (No - They would always be at sea level.)

  • If someone were to walk around the continent at a constant elevation of 100 meters above sea level, what would their path look like on the map? (It would, most likely, be a line around the edge of the continent just inside the coastline.)

    Explain that such a line would be an example of a contour line. A contour line connects points all at the same elevation. A map that uses contour lines to show elevation and the shape of the land is called a topographic map.

    Elaboration (Polar Applications)
    Give each group two copies of the topographic map of Antarctica. Provide a few minutes for them to examine the maps and ask questions. Ask if anyone can figure out what is meant by the term, contour interval. It is the elevation difference between two adjacent contour lines. It is important to know since not all contour lines are labeled with their elevation.

    Pose the following questions:

  • If a point is not on a contour line, can you tell its exact elevation? (No - You only know that it is between the elevation of the two adjacent contour lines.)

  • What is the elevation of the South Pole? (3000 - 4000 meters)

    Explain how they will be using the map to make a three-dimensional model of Antarctica.

    1. Trace the coastline (0 meter contour) on a piece of tagboard. If the paper is too thick to see the lines, use a window or overhead projector as a light source behind the paper. Cut out the tagboard.

    2. Repeat the process for the 1000 meter contour and the following three levels. (The 1000 meter contour includes three small separate pieces.)

    3. Using a piece of tagboard or cardboard as a base, assemble the layers of the model. Place small pieces of cardboard between each layer to act as spacers.

    4. Glue the layers and spacers together being careful to keep them properly aligned. 5. Label the model, using the Map of Antarctica as a key.

    An alternate method can be used by the class to create one or two large-scale models. Place a transparency of The Ice Sheet Surface of Antarctica with a 500 meter contour interval on an overhead projector. Project the image on tagboard that has been hung on the wall. Have students trace and cut out each elevation contour. The resulting nine layers should be assembled and glued together using cardboard spacers.

    Exchange (Students Draw Conclusions)
    Pose the following questions to the class. Have students explain how they used their models and maps to come up with the answers.

  • Is this an exact model of Antarctica? (No, the actual topography is smoother than the stepped appearance of the model. The vertical scale is exaggerated. The amount of exaggeration depends on the thickness of the spacers used.)

  • What is the highest elevation of the Antarctic ice sheet? (between 4000 and 5000 meters)

  • Where are the steepest parts of the ice sheet? (near the edges of the East Antarctic Ice Sheet, along the Transantarctic Mountains, the Antarctic Peninsula)

  • How are steep areas indicated on a (flat) topographic map? (contour lines are close together)

  • How do areas that are flat or gently sloping appear on a topographic map? (contour lines are far apart)

  • What is the topography of the two large ice shelves? (The Ross and Ronne Ice Shelves are both relatively flat with elevations below 1000 meters.)

    Ask students to speculate on the following questions:

  • Where did Antarctica's ice come from? (It has accumulated very slowly from snowfall over a long period of time.)

  • Where does the ice go? (It moves slowly from the highest parts of the ice sheet toward the edges of the continent where it eventually breaks off to form icebergs.)

  • What do you think might be under the ice? (The ice sits atop solid bedrock that displays a variety of topography.)

  • What would Antarctica be like without ice? Display a transparency of the map ANTARCTICA: The Bedrock at Sea Level. This map shows how the continent's coastline would appear if it was ice free.

    A transparency of the Map of ANTARCTICA may be overlaid so that the relationship between the two can be seen. (An ice-free Antarctica would include a large land mass and a series of smaller island. A shallow arm of the sea would mark the location of the South Pole.)

    Conclude by having students contrast the ice sheets that cover East Antarctica and West Antarctica. (The East Antarctic Ice Sheet is much larger, higher [thicker], and it rests mainly on bedrock that is above sea level. The smaller West Antarctic Ice Sheet is based mostly on bedrock that is below sea level.)

    Evaluation (Assessing Student Performance)
    Students can be evaluated on the basis of their:

  • collaboration with the members of their group.
  • successful construction of the model of Antarctica.
  • parcticipation in class discussions. The teacher may want to put the discussion questions in written form on a worksheet or quiz to help assess student understanding.

    data | hook | main | background & resources | student