Most middle school students have not seen or used topographic maps before. Conceptually, it is difficult for kids to see how a 2 dimensional topo map represents elevation. In this activity, students learn how to create and read topo maps. By the end of the activity, they should be able to read a topo map and identify simple geographical features from a map. Teams of students mold a landform out of clay then place it into a clear plastic container. Water is added to the container in 1 cm intervals and students trace the “shoreline” of their model onto a transparency placed on the box lid. The resulting topo map is traded with another group who is then challenged to turn the 2 dimensional map back into a 3 dimensional landform. Several options are provided for creating the final model based on the materials available to the class. In fact, having more than one option of how to create the model often leads to greater understanding of how topo maps represent elevation.
Can understand the construction of topographic maps and the use of contour lines to show the Earth's surface in three dimensions.
Can identify major geographical features on a topographic map.
Can recognize what lines on a topographic map represent.
Can create a topographic map from a 3 dimensional model.
Can create a 3 dimensional model from a topographic map.
135-150 minutes (approximately 3 class periods)
Teams of 2-4 students (I found this activity works best with groups of 3. Students stay engaged and can get access to the materials, but as a teacher, you don’t need to provide as many sets of materials as with groups of 2.)
The class needs
For the clay model each group needs
For making the topo map from the model each group needs
For making models from topographic maps each group needs
Topographic maps are often very difficult for middle school students to understand. They are covered in squiggly lines and unfamiliar symbols and bear little resemblance to the road maps and political maps students may be more familiar with. The key is to use models to help students make sense of these maps.
What is a topographic map (or topo map)? These maps provide a way of showing a 3 dimensional landscape on a 2 dimensional surface. The most distinctive features of a topographic map are the contour lines. Each line represents an imaginary line that connects points that are the same elevation above sea level. Thus, if you walk along a contour line, you would not climb up or down, but stay at the same elevation at all times. USGS maps, the standard topographic map, draw contour lines in brown, labeled at intervals with numbers that represent the elevation above sea level or, in the case of bathymetric maps, the elevation below sea level. Other colors you might find on USGS topo maps are green for vegetation, blue for water features, red for major roads, and grey or black for human developments such as smaller roads, railroads and buildings.
Topo maps are used by most often for navigation so that hikers and explorers can get a sense of the terrain. They are also used by scientists to observe things based on their location and their elevation.
Contour lines are spaced at regular intervals (every 10 feet above sea level is marked with a different line for instance). Thus, the closer 2 lines are together, the steeper the area. Hills can be identified by concentric circles that grow smaller and smaller until you reach the peak of a hill. Depressions such as a dried out pond or the crater of a volcano are generally shown with hatched contour lines.
Familiarity with reading other types of maps – political maps, raised relief maps, road maps, etc. – is useful. I highly recommend Save the Bay’s “Mapping your Watershed” activity that can be downloaded at the bottom of the San Francisco Bay Watershed – Sources section.
Introduction and Making Clay Models
Making a Topo Map of the Model
Making Models from a Topo Map
|Salad Tray Tops||Cardstock Paper||Foam||Clay|
|1. Trim the photocopy of the map so that it just fits on the flat bottom of a tray.
2. Trace the outermost contour line onto the first tray.
3. Trace the next contour line onto a second tray and stack it on top of the first.
4. Continue tracing and stacking until all contour lines have been traced.
| 1. Make a bunch of balls of clay approximately 1 cm tall.
2. On the photocopy of the map, write an “N” on the inside of each contour line on the North side of the island.
3. Hold the photocopy tightly on top of a piece of cardstock. Cut both the photocopy and the cardstock together along the outermost contour line. Label the north side of the cardstock with an N. Set this piece aside.
4. Hold the now smaller photocopy onto a new section of the cardstock and cut out the next contour line and label the north side. Stack this new piece of cardstock on top of the first using some clay balls as spacers to raise it up off the first.
5. Continue cutting out pieces of cardstock and stacking them until all contour lines have been cut out.
Give each group the original and photocopy of a different group’s topo map as well as the other materials. If you want, have students use the maps to predict what the model will look like before they actually make the model. Allow students 30-45 minutes to create their models.Once all the models have been completed, put the original model, the map, and the second model side by side. Were there any problems? How similar are the two models? How are they different? Why aren’t they exactly the same? Look at the models to discover how different features (hills, valleys, ridges, plateaus, etc.) appear on the maps.If you have time, go back to the example topo maps that were shown at the very beginning of this lesson. See whether students are able to identify elevations, features, and identify trends on the maps now.
Activity descriptions and ideas
I first learned how to make topo maps from Eric Muller of the Exploratorium’s Teacher Institute. I changed the method for making the topo map from the models but otherwise our activities are very similar. You can download his "To Topo Two" activity below or from his website with other stellar activities.
USGS has a great description of how to make 3-D model using clear, stacking, salad tray tops.
RAFT describes 2 different ways to create 3-D models. Both are downloadable below or you can access them, and lots of other fabulous idea sheets on the RAFT website. The first “3-D Viewing Topo Lids” uses clear, stacking, salad tray tops. The second, “Making Mountains” uses EVA foam.
If you are an NSTA member, Science Scope had a fabulous article in its October 2005 issue called “Making Sense of Topographic Maps”.
Topographic map information
The best place to learn more about topographic maps is the USGS. For more information about the symbols commonly found on topo maps, see the USGS map symbols page. For more information about how topo maps are created and what they are, see the USGS topo map information page.
S&S Worldwide has the best deal on EVA foam at $15 for 78 sheets.
7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:
f. Read a topographic map and a geologic map for evidence provided on the maps and construct and interpret a simple scale map.
|To Topo Two.pdf||582.47 KB|
|3D Viewing Topo Lids.pdf||147.39 KB|
|Making Mountains.pdf||218.01 KB|
| 1. On the photocopy of the map, write an “N” on the inside of each contour line on the North side of the island.
2. Hold the photocopy tightly on top of a piece of foam. Cut both the photocopy and the foam together along the outermost contour line. Label the north side of the foam with an N. Set this piece aside.
3. Hold the now smaller photocopy onto a new section of the foam and cut out the next contour line and label the north side. Stack this new piece of foam on top of the first, orienting the north sides the same way.
4. Continue cutting out pieces of foam and stacking them until all contour lines have been cut out.
| 1. Roll out a sheet of clay that is approximately 1 cm thick. Make the sheet as even as possible.
2. Place the photocopy on top of the clay sheet and trace the outermost contour line with a pencil. You should create a shadow of the pencil line on the clay below.
3. Use the pencil, a popsicle stick or fingers to cut the clay along the contour line.
4. Roll out a new clay sheet and trace the next contour line on it. Cut another “pancake” and stack it on top of the first.
5. Continue rolling out, cutting and stacking new clay sheets until all contour lines have been cut out.