Our fourth graders explored simple machines such as wheel and axles, levers, the inclined plane, and pulleys. They investigated the effects of balanced and unbalanced forces on the motion of an object. Angelina, Mylo, and Suzi go on a field trip to the zoo and are faced with the design problem of how to rescue a trapped tiger. Using our VEX kits students then applied their knowledge of forces to devise a way to rescue a heavy zoo animal while keeping it safe throughout the process.