Class 2 Catapult

A class 2 lever puts the the fulcrum on on end, the load on the other, and the effort somewhere in between.

In this example, the catapult becomes a class 2 lever when firing because the effort (rubber bands) is in the middle of the lever, however when you pull the catapult back in preparation to fire, it's a class 3 lever because the effort (your hand) is at the end!

Class 3 lever catapult materials laid out before building

Class 3 lever catapult, step 1: Build the base. Use half craft stick pieces along the width and cubes with holes on one side

Class 3 lever catapult, step 2: Reinforce the base

Class 3 lever catapult, step 3: Create triangular uprights and glue cubes at the top

Class 3 lever catapult, step 4: Glue half craft stick pieces to the top

Class 3 lever catapult, step 5: The arm is 2 craft sticks long and has a cube with holes on one end

Class 3 lever catapult, step 6: Cut a small piece of dowel and thread it through the cubes with holes

Class 3 lever catapult, step 8: Pull the rubber band around the top of the supports, and over the catapult arm again

Class 3 lever catapult, step 7: Loop 1 or 2 rubber bands around the catapult arm

Class 3 lever catapult, step 9: Glue and tape a plastic cup onto the end of the arm

Click to expand

Tools and Materials

Testing:

5lbs+ of weight
A large, flat object to create gusts of wind

Tips and Troubleshooting

If the hinge is breaking or falling out of the cubes, then...

Just use 1 rubber band. 2 or more may put too much strain on the dowel
Make the dowel slightly longer so it can't fall out from between the cubes with holes

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