This lab has two activities. In the first, students investigate the arrangement of masses on a center-pivot lever required to produce balance. They will develop the idea that both force and lever arm produce torque, and that both quantities must be considered when trying to produce equilibrium. Force Vectors are used in diagrams. In the second (advanced) activity, students first use pencil and paper to predict an unknown mass from the arrangement used in the first activity. Then they arrange the lever to its off-center position and experimentally estimate the mass of the lever itself.