Place one ball on a piece of wax paper, this is the troposphere.
Place a heavy book on top of the Play Doh.
Place another ball of Play Doh on top of the book, this is the stratosphere.
Place another heavy book on top of the Play Doh.
Continue alternating balls of Play Doh and heavy books until you've accounted for the 5 layers of the atmosphere.
Then unstack the books. You'll find that as you move closer to the Earth (the bottom of the stack), the layers become thinner.
