I’ve always loved building things and learning about physics and engineering. Recently, I became fascinated with catapults and how they work to launch projectiles. As an amateur engineer and tinkerer, I decided to take on the challenge of building my own working miniature catapult using simple household materials – popsicle sticks and rubber bands. Through trial and error, I came up with a design that actually launches small projectiles across the room!
If you want to undertake this fun STEM project, here is my step-by-step guide on how to build a catapult out of popsicle sticks and rubber bands.
- Popsicle sticks – The base and arm of the catapult will be constructed from these. Get a bag of at least 100.
- Rubber bands – Different sizes will be needed. Have a variety pack on hand.
- Glue – White Elmer’s glue works well. This will hold the popsicle sticks together.
- Scissors – To trim popsicle sticks.
- Ruler – For measuring proportions.
- Pencil – For marking cuts and holes.
- Hammer and nail – To create holes for the pivot point.
- Sandpaper – For smoothing rough edges (optional).
- Decorations (optional) – Stickers, paint, markers to decorate the catapult.
- Projectiles – Pom poms, marbles, wadded paper to launch.
Step 1: Create the Base
The base provides stability and a platform to mount the catapult arm onto.
- Take 10 popsicle sticks and glue them together side by side to create a 5″ x 3⁄4″ plank.
- Allow time to dry completely – this may take a few hours.
- Once dry, use sandpaper to smooth any rough edges (optional).
- This plank will be the base of the catapult.
Step 2: Make the Catapult Arm
The arm is essentially a long lever that will hold the projectile pouch on one end.
- Take 1 popsicle stick and measure 3″ from one end. Mark this spot.
- Use scissors to cut the stick at the 3″ mark. Discard the short end.
- Take this 3″ stick and glue 7 full popsicle sticks end to end to create the arm.
- Allow time to dry before moving to next step.
Step 3: Attach Rubber Bands
The rubber bands act as the spring mechanism that provides the power to swing the arm and launch projectiles.
- Take 3 small rubber bands and loop together end to end.
- Tie the ends together to create a triple rubber band chain.
- Stretch the rubber band chain across the popsicle stick arm and hold in place temporarily with a clamp at each end.
Step 4: Create the Pivot Point
The pivot point allows the arm to swing freely back and forth.
- On the base plank, mark a dot 3⁄4″ from each end.
- Use a hammer and nail to poke holes at each dot.
- Insert a pencil through the holes – this will act as the pivot point.
Step 5: Mount Arm Onto Base
Now it’s time to bring the components together!
- With the rubber bands stretched across the arm, carefully lift the arm and place the pencil pivot point into the holes on the base.
- Allow the arm to swing freely but keep the pencil in place.
Step 6: Create Projectile Pouch
The pouch holds the projectiles and releases them when the arm swings forward.
- Take 4 popsicle sticks and glue them together into a square shape. Allow to fully dry.
- On one side of the square, use the pencil tip to poke a small hole in the center.
- Cut a piece of popsicle stick 1″ long and poke a hole in the center.
- Insert a rubber band through the holes and knot it on the inside. This creates a sling pouch.
- Glue the sling pouch to the end of the catapult arm. Allow to dry.
Step 7: Finish and Decorate (Optional)
- Glue on any decorations if desired.
- Give your catapult a fun paint job.
- Use markers or stickers to personalize it.
Now your working mini catapult is ready for launching! Place a projectile in the pouch, pull back and release to fling across the room. Adjust the rubber bands as needed to improve performance. Have fun engineering tweaks and modifications. With some simple materials and the power of potential and kinetic energy, you can feel like an inventor!
I hope you enjoyed this DIY project and learned about the mechanics of catapult technology. Let me know if you try this popsicle stick catapult design and how far it can fling a marble! Science and play can go hand-in-hand.