There are a number of materials that you can use for making a model of earth's layers. These include a hard boiled egg, an apple, sponge ball, aluminium foil, Plaster of Paris, play dough, paper towels, etc. You can get the complete procedure on use of these materials for making such model at the link below:
You can use any kind of coin to be the inner core the circle is the crust because to make earths surface the project has to be rounthe thickest layer can be marked with colored paper all around and the outer core is the circle around theinner core finally show your project and make sur its good then last but not least LABEL YOUR PROJECT THEN YOUR PROJECT IS COMPLETE.
Cookie Dough, graham crackers, honey, jelly, and a hershey kiss