Can Simple Machines Help Us Do Work?
Materials Needed: construction paper (13 cm x 13 cm), straight pin, ruler, unsharpened pencil (with an eraser), 45 cm length of string, one-quart size milk carton, scissors, paper clip, a heavy object Strategy: 1. Students build a model windmill using the 13 cm x 13 cm piece of construction paper, the straight pin, and the unsharpened pencil. 2. Students should cut the top off the milk carton. Then cut 2 deep U-shaped groves in opposite sides of the milk carton. Put a heavy object into the carton to weigh it down. 3. Tie a paper clip to one end of a piece of string. Tape the other end of the string to the writing end of the pencil. 4. Set the windmill into the groves of the milk carton at the edge of a table so that the paper clip on the string hangs freely. 5. Students predict what will happen when air is blown across the top of the windmill so that the blades catch the moving air. 6. Students should (by mouth), lightly blow across the top of the windmill so that the blades catch the
