# Make a Topographic Map!

Maps are a big part of the fourth grade social studies curriculum, but maps in a textbook can seem boring and hard to conceptualize for many students. Topographical maps are a great way to show kids how three-dimensional objects can be represented on a one-dimensional page.

### What You Need:

• Modeling Clay
• Sharp paring knife
• Paper
• Pencil

What You Do:

1. Ask your child to shape his own mountain out of the modeling clay. Encourage him to make the mountain an interesting shape, rather than perfectly symmetrical.
2. Once finished, take the pencil and push two holes in the top of mountain all the way down to the bottom. Then, use the pencil to make horizontal markings on the clay from top to bottom about one inch apart.
3. Assisting your child with the paring knife, cut the top most slice of the mountain. Go slowly and carefully so as not to smoosh your mountain!
4. Put the first slice on your piece of paper, and have your child trace around it. Then color where the two holes in the clay appear on the paper. Place the first slice aside.
5. Now cut your second slice and again trace on the paper. Be sure to line up the holes in the clay with the holes on the paper. Put the second slice aside. Repeat with the rest of your slices.
6. Now have your child put his mountain back together again, and compare the model with his topographic representation. Does the map look like his mountain? Can he find the steepest side? The most gradual slope? The highest point?
7. Discuss with your child why a topo map is a useful tool to have.

What's going on: While modeling clay is usually endless fun all by itself, there's also important lifetime learning here.  Maps provide abstract representation of all the earth's surfaces, and they'll show up in textbooks, classrooms, and all sorts of newspapers and magazines for years to come.  With practice, your child will become fully comfortable with maps of all kinds--and may even ask to climb a mountain or two!

Construct plaster models of areas on topographic maps.  Flood one inch, draw a contour line in marker, flood one more inch, draw another line, etc. Remove water, look at lines from above, to illustrate the concept of contour lines.

Alternatively, use clear salad trays from food stores. Trace one contour line on each tray. When completed, you will have a see-through 3D model of your landscape. For more information, see how to construct a Topo Salad Tray model.

1. Pick a feature you would like to model. Islands work well, because they have well-defined boundaries. But mountains, canyons, or any feature with enough topographic relief will work.
2. Get a topographic map of the feature you want to model. Digital topographic maps can be downloaded free by going to the USGS Store and clicking on "Map Locator" . Or you can order a paper topographic map from the same Web site.
3. Get some clear plastic salad containers (salad trays) or pie covers (any clear, flat, stackable plastic will do). You will need at least 7 or 8 plus a few extras in case of mistakes. They can be purchased at restaurant supply stores or possibly any business that uses them for salads and take-out food. Or save them from your meals. Square salad trays are easier to work with than round trays or pie covers.
4. Find a reducing/enlarging photocopier and use it to adjust the size of the feature you are modeling so it is almost as large as the flat bottom of a plastic salad tray.
5. Once you have the correctly sized photocopy, use a marker to darken just those contour lines you want to transfer to salad trays. In picking the topo lines to transfer, remember two things:

The difference in elevation between adjacent pairs of contour lines should always be the same. This difference is called

the contour interval – the contour interval for the Angel Island model is 100 feet.

The models seem to work best if you have 7 or 8 contour lines (equal 7 or 8 salad trays).

6. Let's call the photocopy with the darkened contour lines the "master copy." Using scissors, trim the master copy so that it just fits the flat bottom of the inside of a salad tray. Getting the fit as tight as possible will help you put the master copy in the same position in each salad tray, and this will help the contour lines on the salad trays line up properly.
7. Position the master copy in the bottom of a salad tray, with the darkened contour lines against the plastic. Secure with tape so the master copy won't move while you are tracing.
8. Looking through the bottom of the salad tray at the master copy, use a permanent marker (black seems to work best) to trace one contour line onto the salad tray*.
9. Remove the master copy and position it in a second tray. Trace another contour line onto the second salad tray.
10. Continue until you have a different contour line on each salad tray. Add the name of the feature, a scale bar (showing how long a mile is, for example), and a north arrow on the top or bottom salad tray. Label each tray with the elevation of the contour line on that tray. Stack them up and be amazed!

* Tip: 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.