Simple Machines

Explaining the principle of the lever. They use the example, such as playing seesaw, pulling the nail. Demonstrating how the lever works and the key about it, fulcrum, emphasis. They move the location of fulcrum and make various experiment. They tell the situation that we use the principle, Playing baseball, sweeping with a broom, cracking the husk, working the bulldozer. digging the ground with scoop.