A Lesson on Making a Topographic Map

Materials and Preparation

A topographic map shows the various elevations of a landscape by using contour lines. These contour lines connect the areas that have the same elevation.

The following materials will be needed to make the topographic map:

• block of modeling clay
• piece of wax paper
• rubber band
• pencil
• metric ruler
• paper
• brown and blue colored pencils
• butter knife

Make a small mountain out of the modeling clay. It needs to be a little over 10 cm high and should include gullies or valleys where streams would run. Place the mountain on the wax paper. Use the rubber band to attach the pencil 2 cm from the end of the ruler as shown in this picture.

Procedure

1. Hold the ruler upright, with the pencil point touching the clay mountain.
2. Mark a line completely around the clay mountain by moving the ruler/pencil around the clay mountain.
3. Move the pencil up to the 4 cm mark on the ruler and repeat step 2.
4. Using the pencil, mark the contour line moving the pencil up 2 cm at a time until you reach the top of the clay mountain.
5. Remove the wax paper and place the clay on a sheet of blank paper. Trace around the outside edge with the brown pencil. Take the mountain off the paper and place it back on the wax paper.
6. Using the butter knife, carefully cut the mountain at the 2 cm elevation line, by moving the knife all around the mountain. Make the cut as flat as possible, trying not to change the shape of the mountain.
7. Remove the wax paper and the bottom slice that you cut off of the mountain. Set the slice aside and place the remainder of the mountain in the center of the first contour line that you traced on the paper. Trace the edge as you did before, and the put the mountain back on the wax paper.
8. Repeat steps 6-8 for the remainder of the contour lines to complete your topographic map of your mountain.
9. Label the first contour you drew 0 cm, the next 2 cm, and continue to the top of the mountain. Use the blue pencil to draw streams in the gullies or valleys.

Analysis

Have the students discuss the following:

• Is your topographic map an accurate representation of the mountain?
• What is the elevation of your mountain?
• Draw a straight line down one side from the top of your mountain to the bottom. Calculate the average slope along this line.

As a challenge, ask students to trade topographic maps with a classmate. Have each student get more modeling clay and try to recreate their partner’s mountain using their topographic map as a guide. Students can place together the sections cut from their original mountain and compare it with their partner’s recreation. Discuss how close they came to the original.