Summary Use everyday levers, and locate the fulcrum and forces in and out, to define what class of lever they are. Works well as a demonstration if time is short. Science content Physics: Motion and Forces, Newton’s Laws, Gravity (K, 2, 6) Physics: Simple and complex Machines (5) Lessons activity is in Simple machines Levers Materials pair of scissors or hole punch and scrap paper clothes peg nutcrackers and nuts in their shell e.g. almonds claw hammer and small nails hammered into a piece of wood Stapler and paper to staple Tweezers or tongs Chopsticks Procedure Set up stations or give students a collection of levers to try. They can use worksheets to record what class of lever, or the location of the fulcrum and the forces, in each lever. Class 1 levers: The fulcrum is in the middle of one (or two) rigid rods. The force in is at one end of the rod and the force out is at the other end. Scissors cutting paper Claw hammer removing nails from wood Hole punch Clothes peg Tongs (that open and close like scissors) Can opener (look closely to see where the rivet and cutter are placed) Class 2 levers: The fulcrum is at one end of the lever arm(s). The force in is at the other end of the lever arm(s). The force out is in the middle of the lever. Nutcracker and nuts Garlic press (Wheelbarrow - purple arrows) Pop (or beer) bottle opener (harder as fulcrum and force out are close together) Car door Class 3 levers: The fulcrum is at one end. The force in is in the middle. The force out is at the other end, and the ends move further with less force. Stapler Tweezers Tongs (with the hinge at one end) Chopsticks Stapler remover Shovel Broom Fishing rod With more space and/or outdoors, add tools from the garden/woodshop: broom (class 3), wheelbarrow (class 2), shovel (class 1), rake (class 3), crowbar (class 1), wrench (class 1), hedge clippers (class 1) A see saw is a class 1 lever. Hockey sticks, baseball bats and many other sport equipment are class 3. One end of the lever moves over a greater distance but with less force, while the other end of the lever moves less far, but with a greater force. Class 1 and 2 levers, we generally move the "force in" (or Effort) end of the lever over a larger distance, but little force is required, while at the other end of the lever ("force out" or Load end), it does not move so far but with a lot of force - enough force to punch a hole or crack a nut. Class 3 levers, we generally move the "force in"/Effort end of the lever less far but with a greater force, while the other end moves further but with little force, so allowing controlled, fine movements to pick up materials. Attached documents everyday_levers_worksheet.pdf levers_worksheet.pdf Notes Can be run as a fast demo. Grades taught Gr K Gr 1 Gr 2 Gr 3 Gr 4 Gr 5 Gr 6 Gr 7
