Identify all 3 classes of lever & different types of pulley systems; test them to determine how they operate. Identify key parts of levers & pulleys. Compare & contrast how different levers & pulleys function. Discuss how levers & pulleys change the direction &/or the amount of force applied to do work. Teacher/s guide included. Set Includes: 178 pieces to build 8 real world models, 1 at a time. 16-page full-color building instruction booklet with key facts on each model, & real world pictures. Plastic storage case with moveable dividers & transparent locking lid. Includes teacher's guide on CD. Grades 3-5. - SKU: OS15901