Box D Simple Machines, ForcesPhysical World Physics 2 Experiments, learning and experimenting with simple machines and forces. Hands on building a "skateboard" and a catapult. Generous materials for 2 experiments for 30 students, or 2 experiments for 60 students working with a buddy. Workbook and teacher materials included. 2 separate experiments designed to make students think differently as they draw similarities and differences between the interesting outcomes.