Physics Discovery. With Physics Discovery, you will build 12 models and then conduct experiments with the models to learn about forces and simple machines. Each model demonstrates a fundamental idea in mechanical physics. For example, you can build a balance scale to learn about lever arms, a freight elevator to learn about pulleys, a bicycle to learn about wheels, a motion picture machine to learn about centripetal and centrifugal forces, and a transmission to learn about gears. Physics Discovery is a smaller, introductory companion to the best-selling Physics Workshop kit. It contains different building projects and experiments, and uses parts that are compatible with all of the kits in this Physics line. The 32-page book offers illustrated instructions for building projects and experiments. Ages 8 and up.