Engage (10 – 15 minutes):
1. Show students an “Earth” view of your school using Google Maps. Discuss visible landmarks on this photo view (trees, school building, roads, fields, etc.) Change to a “Street” view map to compare and contrast the two maps. Have partners turn and talk about the following questions:
- What is visible on one type of map but not the other?
- When would the photographic “Earth” view be more useful?
- When would a street map be more useful?
- What information about our school campus is not visible on either map? Is there another type of map we could use to get this information? (These questions will help you determine prior knowledge about topographic maps.)
2. Tell students they will be designing a bike race course around the neighborhood. Why would they want to consider elevation when designing their path? Have small groups discuss features that would make the best bike course. What would make the race faster? Possible responses could be a straight course or going downhill. What would slow down the riders? Possible responses could be lots of turns, going uphill, etc. What would make the race more exciting? (Possible responses could be obstacles, jumps, etc.)
3. Have students work in small groups to list the land features they need to know about in order to plan the best race.
Explore (40 – 50 minutes):
- Explain to students they will investigate a new type of map, called a topographic map, to help them plan their bike race routes. A topographic map is a map that shows the elevation of land features. Explain they will make their own mountains with clay and constructing a topographic map of their mountains to better understand how to use these types of maps.
- Students will work in groups of 2 – 3 students. Give each group a fist-size ball of modeling clay or play-dough to use to create mountains. If play-dough is used, make sure it is firm enough to maintain its shape when sliced with dental floss. Encourage students to make their mountains unique, because they will need to be able to tell their mountain apart from the others in the class.
- Place the mountain on a piece of paper or cardboard and trace the outer edge of the mountain with a marker. Place two pencils through the mountain vertically at its peak and mark two dots on the paper to show the orientation of the mountain.
- Measure the height of the mountain in 1 cm increments. Separate each 1 cm layer of the mountain using dental floss. Orient the second layer using the dots on the paper, then trace the outline to show 1 cm elevation. Continue tracing each layer to make a topographic map. For full instructions, go to NASA Space Place.
Explain (15 – 20 minutes):
- Have students reassemble their mountains. Explain that the outline of each layer on the map is called a contour line. Students should indicate the elevation of each line. (The bottom of the mountain is the outer contour line, which has an elevation of 0 cm; the next interior line shows the 1 cm elevation, the next 2 cm, etc.)
- Discuss what the distance between the contour lines means on the clay mountain. (The lines that are closer together show a steep hill. When the lines are farther apart it shows a more gradual rise.) When students can explain how their maps match their mountains, have students place their mountains in a line on one side of the classroom and collect the topographic maps.
- Shuffle the topographic maps and redistribute them to groups so they can match another group’s map to its corresponding mountain. Groups will select the mountain that they think is represented by their map. Each group will explain to the class why they believe this is the matching mountain based on data from the map. The group that made the mountain will then tell them if they chose the correct mountain.
- Show students a topographic map of your school using the Enviromapper site. Have students identify areas of high and low elevation on the school campus or in the neighborhood. Where are the steepest hills? What are the flattest areas?
Elaborate (15 – 20 minutes):
Using their knowledge of topographic maps, students will work in small groups to create a one-mile (or any other set distance) bike trail through the school neighborhood that will result in the most exciting (but still safe) race. Give students printed copies of the topographic neighborhood map to use in the planning process.
As students plan, have them discuss these questions:
- Will we only use streets, or will there be some “off road” components to the race?
- What elevations will make the race go faster? What parts of the neighborhood will slow the racers down?
- What areas should be avoided to keep the race safe?