Grades 4 & up. Build all 5 simple machines at once in science centers. Students can construct, examine and explain simple machines to develop a deeper understanding of how they make work easier. Contains enough pieces to build a lever, pulley, inclined plane, wheel and axle, and wedge all at the same time! Modify machines with 4 included weights (two 5g and two 10g), plus 8 included rubber bands to explore effort, force, load, motion and distance. Includes 63 pieces and activity guide.