Each group needs:

• 6 or 7 books, each smaller than 1-inch (2.5-cm) thick, totaling ~ 10 lbs (~4.5 kg)
• modeling clay piece, 1 inch x 1 inch x 3 inches (2.5 cm x 2.5 cm x 7.6 cm)
• wax paper or plastic wrap, to keep clay pieces from drying out
• measuring stick or ruler with 1/16-inch (1-mm) marks
• Materials Data Sheet, one per person

For the entire class to share:

• scale, to weigh books
• scrap paper
• tape