This is a great way to teach the earth's layers. It is pretty simple, you will only need the following ingredients:
The Inner Core : a gum drop or dots
The Outer Core: a marshmallow
The Mantle: rice crispy treats
The Crust: Hershey's hard shell chocolate
For a full set of directions, head here:
I usually send the directions home with kids during this unit. It's a great at home family activity! I suggest only attempting this in class if you have parent volunteers!