When a flat topographical map is transformed into a 3D model of the area, geography and map skills become real, understandable concepts.
Select a topographical map that you wish to turn into a 3D model. The more lines on a map, the harder it will be to create. Start simple.
Understand what you are looking at: A topographic map shows elevation. Each "circle" (these are never perfect circles - usually very squiggly) indicates how high above sea level the area is. These circles are called contour lines. As contour lines get smaller and closer together, this symbolizes the land getting higher and steeper. The smallest contour line is the highest point on the map.
Cut out the biggest circle, or contour line. There will be smaller lines in the middle. Ignore those for now. Trace your cut-out on cardboard and cut the cardboard out. This is the base of your 3D model.
Repeat this procedure for the rest of the lines on the topographic map. Cut out each contour line circle, trace onto cardboard, and cut out the cardboard. Your circles should get smaller and smaller. Go ahead and discard your cut-up map pieces once you have the cardboard cut-outs to keep. Be sure to keep the cardboard cutouts stacked up in order, so the biggest piece is on the bottom.
Once all your cardboard pieces are cut out, it's time to start the papier-mâché. With the papier-mâché, glue each cardboard piece to one below it. Be sure to keep the cardboard in order. When you are finished, you may papier-mâché strips of newspaper to cover the cardboard pieces. This gives the model a more smooth look.
Let the papier-mâché dry and then paint and label your model. Use your model to teach others how topography maps symbolize elevation, but your 3D model actually shows elevation.
Don't use flour and water as a papier-mâché substitute. Buy (a lot of) the actual glue from a art supply store.
With my 8th graders, I have them create their own topographical maps of a fictional island, with only 3-7 contour lines inside. This is much easier to work with then an actual topography map.
Don't worry about perfection with this project. A lost cardboard piece will not wreck the whole model.