Build a Craft Stick Catapult

A craft stick catapult is a miniature siege weapon made from stacked popsicle sticks and rubber bands, and it is one of the most satisfying STEM challenges in the preschool engineering repertoire. When the arm is pulled back and released, it snaps forward with surprising force, launching a small projectile (a marshmallow, a pom-pom, a small paper ball) across a measurable distance. The build takes 10 minutes; the testing and modification take as long as you want.

The catapult directly demonstrates potential and kinetic energy: energy is stored (potential) as the arm is bent backward, and released as motion (kinetic) when the arm snaps forward. This is physics made tactile—your child can feel the stored energy in the bent arm and watch it convert to launched-projectile motion.

What You'll Need

• Craft sticks (popsicle sticks) — About 10.
• Rubber bands — 4–6.
• A plastic spoon — The projectile holder.
• A marshmallow, pom-pom, or small paper ball — The projectile.
• A ruler or measuring tape — For measuring launch distance.
• A target — A cup, a paper plate circle, anything to aim at.

How to Do It

1. Build the stack base. Stack 7–8 craft sticks and wrap tightly with rubber bands at both ends. This stack provides the tension platform.

2. Add the launch arm. Separate the top stick of the stack and wedge one additional craft stick vertically between it and the rest of the stack, near one end. This creates a lever arrangement.

3. Attach the spoon. Tape or rubber-band the plastic spoon to the top of the single separated stick (the launch arm), bowl facing up. This is where the projectile will sit.

4. Fire the catapult. Place the marshmallow in the spoon bowl. Hold the base stable with one hand and push the spoon arm down with the other, then release. The arm snaps up, launching the projectile.

5. Measure and record. Mark where the projectile lands with tape. Measure the distance. Try to improve the distance by adjusting the catapult.

6. Modify for distance. Adjust the fulcrum position (the vertical stick placement), add more rubber bands for more tension, or change the spoon position. Each change is a hypothesis; each launch tests it.

🎓 Skills Your Child Will Develop

• Potential and Kinetic Energy — Storing energy in a bent stick and releasing it as projectile motion is a direct, tactile experience of one of physics' most important concepts.

• Lever Mechanics — Understanding that the position of the fulcrum (the vertical stick) affects how much force is generated builds intuition for lever mechanics—one of the six simple machines.

• Experimental Measurement — Measuring launch distance, recording results, changing one variable, and measuring again is quantitative experimental design.

• Projectile Physics — Noticing that the projectile follows a curved (parabolic) path and that launch angle affects distance introduces projectile motion concepts in a playful, observable format.

My Two Cents

The craft stick catapult belongs in the permanent home science collection because it's instantly compelling, endlessly variable, and builds real physics intuition through the specific pleasure of making things fly. Children who build catapults understand energy storage not because they've been told about it, but because they've felt the stick bend and released it.