By Kathy Hynes
Topographic maps show changes in elevation over an area of land. Many topographic maps are prepared by the United State Geological Survey. Many people use topographic maps such as engineers, geologist, hikers and pilots. The landscape represented by topographic maps is interpreted by reading the contour lines. Contour lines spaced very close together represent land areas that are steep. Widely spaced contour lines represent flat land areas. Contour lines do not cross. If they did, they would indicate that two different elevations exist at the same spot. In addition to geologic information, topographic maps also include geographic and demographic information.
Students will use their knowledge of topographic maps and contour lines to construct a cross section diagram showing the changes in elevation represented by a cookie island. They will also construct a model using topographic lines on paper. Then they will label geographic features on their island map. This activity helps students visualize what a topographic map represents and demonstrate their understanding of contour lines.
- A chocolate chip cookie
- a napkin
- metric ruler
- drawing paper for each student
- Tell the students to pretend that their cookie is a Pacific Island surrounded by water and they are to construct a topographic map of the island.
- First they will draw a profile of their cookie island showing changes in elevation by observing the cookie from the side. They should make this drawing as accurate as possible, using a ruler to determine the highest point and diameter of the island in centimeters.
- Below this profile the students will trace around the edge of the cookie on the paper. This circle represents the shape of the island and an elevation at sea level.
- Using a ruler vertically beside the cookie, determine how many centimeters the highest point is on the island. Convert the centimeters to hundreds of feet to make your scale and determine contour intervals.
- Represent the landscape of your island with contour lines within the outline on your paper. Be sure to label elevation in some manner.
- Indicate 3 different landforms on your map.
- Where would you build a house on this island? Why did you choose this place?
- 8. Give your map a title, a compass rose, a scale and a legend.
Data Table: The map construction.
- What is the contour interval on your map?
- What area of your island has contour lines that are farthest apart?
- What kind of land form has lines that are closest together?
- What can one learn about your island from the topographic map you constructed?
- How was the map helpful for you to choose a place to build a house?