Simple Machines — Lever, Pulley, Inclined Plane

Simple machines multiply force. A lever lifts a heavy stone with a small push; a pulley changes direction; a ramp lets a child push a cart up rather than lift it. Discovering mechanical advantage numerically — 'less force, more distance' — is the control.

• Framework: Montessori
• Unit: Cultural Studies
• Learning area: Physical Science
• Level: Ages 6-8

Objectives

• Identify the six simple machines: lever, pulley, wheel and axle, inclined plane, wedge, screw
• Build and test each one
• Understand mechanical advantage
• Find simple machines in daily life

Materials

• Small kit of simple machines (wooden lever, pulley system, inclined plane, wedge, screw)
• Weights for testing
• Spring scale for measuring force
• Recording sheet

Instructions

1. Introduce each machine one at a time. 2. Test a lever: push down with the spring scale to lift a weight; measure force. 3. Change fulcrum position; measure again. 4. Test a pulley: lift a weight directly; now lift through the pulley; compare force. 5. Roll a weight up an inclined plane; measure the force needed. 6. Compare to lifting it straight up. 7. Record results in a table. 8. Find each simple machine in the classroom (scissors = lever; doorstop = wedge; screw = screw). 9. Design a Rube Goldberg contraption using three simple machines.

Educator tip

Let children design their own machines. A Rube Goldberg day is the joyful culmination.

Assessment

Note accurate identification, measurement, and understanding of mechanical advantage.

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