This collection of physics animations lets students see and understand the principles behind the motion of objects under different circumstances, including single and double springs, pendulums, roller coasters, and various combinations of these. Users can vary the parameters of the animations (mass, spring elasticity and length, track shape, gravitational acceleration, and others) and see how the motion changes. Many of the animations are accompanied by graphs that trace position, acceleration, velocity, angle of motion, and other parameters. There are also two simulations of collisions of objects. Each simulation is also accompanied by the mathematics that governs the motions being illustrated, and some feature puzzle questions.