Catapults

Concept: Levers
Levers are a type of simple machine that can help lift heavy loads with much less effort. A lever consists of three basic parts: the beam, the fulcrum, and the load. The beam is a plank which balances on a fixed point. The point on which the beam pivots is called the fulcrum. The load is the object that requires moving. Effort is the force that moves the lever.

Read Aloud: Gizmos and Gadgets by Jill Frankel Hauser

Ingredients:

      ·         9 Craft Sticks
      ·         4-6 Rubber Bands
      ·         1 Plastic Spoon

      ·         Mini Marshmallows

 Demonstration:

      ·         Count out 7 craft sticks and stack them. Tie a rubber band tightly around one end of the stack.

      ·         Tie another rubber band tightly around the opposite end so all 7 sticks are bound together.

      ·         Take 2 more sticks and stack them. Tie a rubber band tightly around one end of this stack as well.

      ·         Slide the stack of 7 sticks between the stack of 2 sticks.

      ·         Tie a rubber band in a cross fashion to secure all of the sticks together.

      ·         Use a few rubber bands to attach a plastic spoon on the end of the catapult.

Experiment:

·         Which catapult was able to launch a marshmallow the farthest?

·         What element of that catapult's design made it work the best?

Observations:
Catapults use levers to work. For this catapult, craft sticks form the beam and the fulcrum. The lever moves the load, which is the marshmallow, when your hand pulls back the spoon and applies force on the rubber bands.