In the first lab, students will investigate the arrangements of weights that result in equilibrium (balance) in the lever system. They will find that both the force and the distance from the fulcrum are important in evaluating the system. This investigation leads naturally into a study of torque. In the next three labs, students will investigate the three classes of levers, organized according to the arrangement of the input and output forces and the fulcrum. They will compare the levers and determine which class is useful in different situations.