This kit allows students to build a machine which has fascinated people for hundreds of years – the catapult. After young engineers complete the model, they become physicists as they transform stored energy into kinetic energy of a projectile. Adjustable pads on the crossbar alter the catapult’s trajectory, allowing students to change variables and study the effects of their experiments. Twisting the rope helps visualize torsion, and releasing the projectile demonstrates mechanical advantage. Lessons apply to real life as students use these physics concepts in everything from twisting off bottle caps to opening a car door. Completed model measures 10"L x 6"W x 5"H. Kit includes precision-drilled wood parts, plasticine projectile, and step-by-step building instructions. Recommended for Elementary and up.