How can you make a 3-D model of the Earth's layers?

Depicting the Earth's layers as a 3-D model can be done using paper mache, or in a fun, edible cake form; however, using modeling or Baker's clay are more common methods. The following steps outline the procedure for using Baker's clay.

1. The Baker's clay should first be split into the following relative proportions (using a meter stick or ruler to measure): 0.7 percent for the inner core; 15.7 percent for the outer core; 82.0 percent for the mantle.
2. Next, each of these volumes should be rolled into a sphere.
3. The outer core sphere should be cut in half and, using the fingers or thumbs, a dip large enough to accommodate one half of the inner core sphere should be pressed into each of the outer core halves.
4. The process is then repeated for the mantle, which should house both the outer and inner cores when pressed back together.
5. The resulting structure is then to be cut in half and baked until dry in a 200 degree Fahrenheit oven.
6. The crust would be far too thin to model at this scale, so it should be painted on when the model is dry.