Levers

   The lever was one of the earliest machines to be used. Levers help us lift weights with less effort.

Time to Catapult!

 Today, we are going to build our own catapults to show how levers make work easier.  Following the directions below, which are also on your worksheet, build your catapult and use it to test how they make work easier. Use your findings to complete your "Catapult Shooter" Worksheet.

Purpose: 

          How does a lever make work easier?

Materials:

            Popsicle stick

          meter stick

          5 marshmallows

          pencil

Procedure:

            1. Lay your group's Popsicle stick across the pencil

          2. Place one marshmallow on the end of the stick that is touching the floor.

          3. Write "1" on the Popsicle stick at the spot where it lies across the pencil (the fulcrum).

          4. Flip the marshmallow by hitting the end of the stick that is in the air.

          5. Measure the distance the marshmallow flew. Measure from the pencil.

          6. Record the distance on your chart.

          7. Change the location of the fulcrum-the spot where the Popsicle stick crosses the pencil. Write "2" on the stick where it now crosses the pencil.

          8. Repeat steps 2, 4, 5, and 6. When you hit the end of the stick each time, try to use the same amount of force each time. (repeat these steps 4 times)

Observations:

          What did you notice happening each time you changed the location of the fulcrum?

          What happened to the distance that your marshmallow flew each time you changed the location of the fulcrum?

Conclusions:

           How did the location of the fulcrum affect the distance the marshmallow flew?

           Does the positioning of the fulcrum affect the distance an object will fly, if so how?