We are studying the layers of the earth. Yesterday the students made models of he earth using homemade play dough. I made the dough using 1 cup flour,1 cup water, 1/2 cup salt, 1 tbsp oil, 2 tsp cream of tartar and food coloring. Mix it all in a pot over low heat until it starts to stick together and forms a ball. Let it cool then put it in a bag or Tupperware. I made one batch for the core (red) and crust (brown-make orange then add a drop of blue until you get the brown you want) and then two batches of the outer core (orange) and the mantle (yellow).