Explain that a lever is a rigid long bar that can pivot (or tip or rotate) at one point over a fulcrum.
Students do a selection of the activities (two in an hour, three in 1.5 hrs).
For a lever to project a ball students set up a paint stick lever arm on a wooden stick fulcrum, to project a foil ball. They experiment with the location of the fulcrum and the size of the force exerted on on end of the lever arm to see how they affect the height that the projected object can go.
Students can compare the forces in a lever as the position of the fulcrum changes, using a metre-long lever arm with a brick on one end.
Levers for lifting heavy objects demonstrates how with a long lever arm and the fulcrum near the load, a very heavy object (a large rock) can be lifted.
Students experience household levers (from all three classes of levers).