science-class.net. I've tried and tried to link to the original instructions, but am getting error messages, so I will recreate the instructions for you. If I later find the link to be working, I'll edit this to add that information.
You'll need blue, brown, yellow and black construction paper, as well as scissors, rulers and glue. If you have compasses (the kind for drawing circles), and your students are suitably able to use them, they would make everything a bit easier.
Cut out a blue 22 cm circle, labeled "6 - 40 miles" to represent the crust.
Cut out a brown 18 cm circle, labeled "1800 miles" to represent the mantle.
Cut out a yellow 15 cm circle, labeled "1375 miles" to represent the outer core.
Cut out a black 7 cm circle, labeled "1750 miles" to represent the inner core.
I like to have the students evaluate the pros and cons of this type of model, as well as compare it to the pros and cons of the Layers of the Earth bookmarks made previously.