TOPS #22 Machines

Your students will construct levers from a meter stick and a rubber stopper; pulleys from paper clips and thread; inclined planes from pieces of cardboard. They will use spring scales to weigh loads, measure effort, and thereby calculate efficiency. In each case they will find that machines save effort but never reduce work. They'll build a wheel and axle machine, examine gear ratios, even calculate the horsepower generated in climbing a flight of stairs. Imagine the smallest kid in your class winning a pulley tug-of-war against the strongest. Machines is great fun that your students will not easily forget.