Time
135-150 minutes (approximately 3 class periods)
Grouping
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.)
Materials
The class needs
- several example topographic maps for students to examine before they begin (see Sources section below)
- optional (though highly recommended) – raised relief map of state or local area (see San Francisco Bay Watershed – Sources for information on where to buy these maps)
For the clay model each group needs
- 1 fist-sized lump of synthetic Plasticine clay (Play-Doh will work, however, it is somewhat water-soluble and therefore becomes slimy after the water box step.)
- 1 small bead of clay of a different color (for marking the top of the mountain)
- 1 half-sheet of transparency film (the sheet of transparency needs to fit inside the plastic container below)
For making the topo map from the model each group needs
- 1 full-sheet of transparency film
- 1 fine-tip Sharpie or overhead marking pen (Permanent pens won’t smudge if a drop of water gets on their map. On the other hand, students can’t make corrections if they make a mistake.)
- 1 plastic shoebox-sized container, at least 8 cm (3 inches) tall (The ones from the Watersheds and Wetlands activity work fine.)
- 1 flat, transparent lid for the plastic container (Most plastic storage containers come with textured, opaque lids. You need something like a sheet a clear Plexiglas that can sit over the top of the box and which students can write on. I recently discovered these plastic salad boxes at Smart and Final that provide a container and a lid in one!)
- access to a pitcher of water with 4 drops blue food coloring (I had 2 teams share 1 pitcher)
- 1 plastic ruler
For making models from topographic maps each group needs
- 2 copies of a topographic map (1 original and 1 photocopy)
- 1-2 pairs of scissors
- 1 ruler
- 1 fine-tip Sharpie or overhead marking pen
- one of the following:
-
- 7-8 clear, stacking salad tray tops (available at Smart and Final or other restaurant supply stores)
- 3-4 sheets cardstock paper and a lemon sized ball of clay
- 3-4 sheets of EVA foam
- 1 fist-sized lump of Plasticine clay
Setting
classroom
