Objectives:  Students will be able to:
 

• Identify the wheel and axle as a simple machine.
• Explain the gears are wheels and axles that use friction to function
• Recognize wheels and axles in compound machines

• 30-60 minutes
• 2 small plastic cars, one with wheels, one without
• 1 eggbeater
• 2, 8x6 pieces of cardboard for each student
• blackline drawing of gears to fit on one of the pieces of cardboard
• 2 paper fasteners for each student

• wheel and axle
• gears

         Review simple machines so far studied.  Show the plastic cars.  If I push these cars, which one will go faster and farther?  Why?  This car travels faster and farther because it uses a simple machine.  Write wheel and axle on the board.  Today we'll look at how the wheel and axle helps people do jobs faster and easier.
         A wheel alone is not a simple machine.  It must have an axle with it to make it work.  A doorknob is a wheel and axle.  We turn the knob,(the wheel) and the axle turns, unlatching the door.  What other toys or machine have wheels and axles?  Write a list on the board.
          Some machines have wheels and axles that turn other wheels and axles.  These are called gears.  Write gears on the chalkboard.  Ususally gears have little teeth that mesh with each other and friction helps them grip and turn.  Shoe the egg beater.  There are gears on this machine.  Point to the handle and gear and each gear that turns the beaters.  This machine helps us do more work without using more effort.