In this activity, learners explore dinosaur fossils by making cast models of a T. rex. First, learners read about and research how dinosaur fossils form. Next, learners make impressions in clay using a T. rex tooth. Finally, learners use plaster of paris to make casts of a T. rex tooth or claw. Although this activity is written as a two-day lesson, it could be easily modified into a one-day lesson. However, the wet plaster must dry overnight. This activity is featured on pp. 31-32 of the "Dinosphere" unit of study for K-2 learners.