Test models and identify whether the wheel turns the axle or the axle turns the wheel. Discuss how a handle acts like a wheel. Discuss whether the wheel and axle system increases applied force or distance traveled. Identify appropriate places where wheels and axles are used. Identify and differentiate inclined plane, wedge and screw and test them to determine how they operate. Compare and contrast how these different machines function & determine why they are categorized together. Set Includes: 221 pieces to build 7 real world models, one at a time. 16-page full-color building instruction booklet with key facts on each model, and real world pictures. Plastic storage case with moveable dividers and transparent locking lid. Includes teacher's guide on CD. Grades 3-5. - SKU: OS15904