STEM Challenges

STEM Challenge #3

Week 3 Supplies

  • 5 popsicle sticks
  • 3+ rubber bands
  • Plastic spoon
  • Pom poms, ping pong balls, marshmallows or other “safe ammunition”

Week 3 Instructions

The catapult was used as a weapon for early civilizations for hundreds of years. It was intended to increase the power of a crossbow, but became a much more versatile technology that we still use today. You can make a simplified version of this with common household items! (The Circuit Breakers Robotics Team also has part kits available for pickup at the Medical Lake Library)  

To begin, stack some sticks (we recommend about 5) on top of each other and secure both ends with a rubber band. Then, separately stack 2 sticks and secure just one end with a rubber band. Open up the 2 and slide your stack of 5 in between them, so it looks kind of like a plane. Attach a plastic spoon on top of the sticks, using glue or tape. Cross one more rubber band round where the sticks intersect, in an X shape, to secure your contraption into place. It’s that simple! To begin using your fun contraption, load in a pom pom by placing in the spoon, then just pull back on your spoon to charge and release your weapon!  

If you need additional help or information, check out

Here are some activities to try after building your catapult:

  • The Dunk: Try shooting pom poms into a small or large cup. Try at different distances and heights for an extra challenge.
  • The Lord of the Rings: Line up small and light toys on a box or ledge, try and knock them down. For an extra challenge- try to consecutively knock down all the toys without missing once, if you miss- you have to reset them all and try again.
  • Hawkeye: Draw a paper target- go for a bullseye!

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