A hands-on lever experiment using a popsicle-stick catapult to launch soft projectiles, exploring how a lever turns a press into a flight.
- Build the catapult together (adults handle any glue). Stack 5 craft sticks and wrap a rubber band around each end. Take 2 more sticks, place them in a “V” with a rubber band binding one end. Slide the stack of 5 between the open arms of the V near the bound end. Lock everything in place with a rubber band where the stack and arms cross. Tape or glue a plastic spoon or bottle cap onto the top arm — that’s the launching cup.
- Place the catapult on a table or floor. Load the cup with a soft projectile — pom-pom, mini marshmallow, balled-up paper.
- The child presses the top arm down with one finger and lets go. Whoosh — the projectile flies.
- Investigate together: “What happens if you press harder? What if the cup is closer to the bottom of the arm? What flies farthest — pom-pom, paper ball, or marshmallow?”
- Set up a target — a bowl on a chair, a paper plate on the floor — and try to land the projectile inside.
Variation: aim at stacked-cup pyramids (“knock down the most cups in 5 launches”). Build two catapults for a family contest. Mark each child’s longest launch on the floor with a strip of tape that stays for the week.
Requirements
- Space: A clear "front yard" of about 2–3 meters in front of the catapult, away from breakables and faces
- Surface: Any flat surface (table, floor, picnic blanket outdoors)
- Materials: 7 craft/popsicle sticks per catapult, 4–5 rubber bands, a plastic spoon or milk-bottle cap, soft projectiles (pom-poms, mini marshmallows, paper balls); optional paper cups or plates as targets, hot glue (adult use only)
- Participants: 1 adult + 1 child for build (adult does any cutting/gluing); child operates after build; great with siblings or playdate friends
- Supervision: Moderate — adult builds and supervises launches; never aim at faces
Rationale & Objective
A popsicle-stick catapult is a clean working example of a lever, one of the six classic simple machines (Generation Genius; Science Buddies; Little Bins for Little Hands). At age 5 children are not yet ready for formal physics, but the conceptual seeds of force, energy, and trade-offs are forming through play (HighScope KDIs 51–53; Head Start ELOF Scientific Reasoning). The activity builds fine motor control (loading and pressing the lever), spatial reasoning (aiming at a target), and predictive reasoning (“if I press harder, will it go farther?”), and connects to broader engineering thinking when the child starts modifying the design.
Progress Indicators
- Early: presses the arm randomly; doesn’t aim; loses interest after a few launches; needs adult to load and reset
- Developing: presses with intent and watches where the projectile lands; loads the cup independently; begins to aim toward a general target
- Proficient: aims at specific targets and adjusts after misses; predicts what will happen if they press harder or change projectiles; sustains 10–15 minutes; explains in simple words how it works (“the stick goes down, the marshmallow goes up”)
- Advanced: rebuilds or modifies the catapult to launch farther; sets up own target challenges; understands the trade-off between distance and accuracy; can call the catapult a “lever” or “simple machine”
Safety Notes
- Only use soft projectiles — pom-poms, mini marshmallows, balled tissue. No hard objects, pebbles, coins, or pencils
- Aim away from faces, eyes, pets, and electronics. Establish a “no people” target zone before launching
- Rubber bands can snap during the build — adults handle the rubber-band assembly
- Mini marshmallows are a choking hazard for siblings under 3 and shouldn’t be eaten after launching
- Hot glue is for adult assembly only
Hints
- Playfulness: name the catapult (“Mr. Boing!”); decorate with stickers; give projectiles voices as they fly. “Pom-pom mail to the castle!”
- Sustain interest: rotate targets weekly — knock-over cup pyramids, hoops on the floor, distance lines. Keep a “flight log” of longest launches
- Common mistake: building once and never modifying. The richest learning is in changing the design (stack height, cup placement) and seeing what changes
- Limited space: a 1-meter table is enough. Soft projectiles in a small living room are safe with a clear “front yard” zone of cushions
- Cross-domain: measure launch distance with shoe-lengths or a ruler (numeracy); describe trajectories with words like “high, far, curve” (vocabulary); draw the path of flight (visual arts); take turns with a sibling (social-emotional)
- Progression: launch and watch → aim at a wide target → aim at a small target → adjust force for distance → modify the design → compare two catapults → invent a new launching machine
Sources
- Generation Genius — Popsicle Stick Catapult, Simple Machines Activity for Kids
- Science Buddies — Build a Popsicle Stick Catapult STEM Activity
- Little Bins for Little Hands — Popsicle Stick Catapult for STEM
- HighScope KDIs 51 (Experimenting), 52 (Predicting), 53 (Tools and Technology)
- Head Start ELOF — Scientific Reasoning sub-domain
- Engineering is Elementary (Museum of Science, Boston)
- TeachEngineering — Simple Machines Lesson
- Singapore NEL — Discovery of the World