Introduction to Topographic Maps

Materials / Preparation

• One Computer with Internet access and a printer
• Each group of students will need:
  7-8 plastic salad trays per group
  1 copy of the topo map
  1 black marker
  1 pair of scissors
• To prepare the copies of topo maps, you will need a reducing/enlarging photocopier to make these copies. Go to Topographic Salad-Tray Model, scroll to the bottom of the page, and download and print the map of Angel island.
• You can print out the instructions from the top link on Topographic Salad-Tray Model

Grouping

Groups of 2-3 if you have sufficient materials

Teacher tips

Some of the instructions on the website pertain only to what the teacher should do. You will need to direct students to begin at step 5 if you print out copies for students.

Oil from your hands can prevent the marker from writing on the plastic. A tissue beneath your writing hand (and used to wipe each tray before you start tracing) will help.

A great alternative assignment for teaching topo maps can be found at Mapping Potato Island. However, be aware that students may become confused about the connection between sea level rise and topo maps in this activity.

Procedure

1. Class discussion.
   a. “Yesterday we found out that not all parts of the Earth were affected in the same way by sea level rise. What conclusion did we come to about why that is?” Elicit the response of differing topography, and review the meaning of the word if necessary.
   b. Tell students that today they will be learning more about what a topo map is and how to use it by making a model.
2. Pass out the copied map of Angel Island to each student, and discuss: “What is this a map of? How do we know? About how wide is this island in feet? Do you think that this island is flat or mountainous? Can you think of a way that we might be able to figure this out? What do the lines mean?”
3. Define contour line and contour interval on the board. Draw a couple of very simple contour maps on the board and ask students some questions to check for understanding, such as “If you were walking across this area, which direction would lead you uphill? Which direction would lead you downhill? What is the distance between two lines? Where is the steepest part of the map?”
   a. Then draw in two points on your topo map diagram and ask students “What path would be the easiest to take to get between these two points? Why? If you were to go in a straight line between these two points, how much elevation would you gain?”
   b.You may want to have students record the definition of contours, and contour intervals in their field notebooks along with a brief description of how to find the change in elevation.
4. Pass out the materials for the activity and review the instruction with the students. If you choose to pass out the printed copy of directions, make sure students know that they should begin at step 5 and proceed from there.
5. When students have completed the contour lines on each tray, ask them to stack their trays in order to create a 3-D model.
6. Ask students to review what they have learned about topo maps from this activity. Let them know that reading a topo map is a good skill to have and that it will prove useful in the next part of their exploration of sea level change.

Homework

If students did not complete their salad tray model, assign its completion as homework.

Resources used

Topographic Salad-Tray Model
http://www.teachingboxes.org/catalog.jsp?id=DLESE-000-000-008-867

Mapping Potato Island
http://www.teachingboxes.org/catalog.jsp?id=DLESE-000-000-008-867