How to Build a Strong Catapult (with Pictures) - wikiHow
Amazon.com: Catapult Kit - Build Yourself - STEM Learning - Comes Explore Force, Acceleration, Center of Mass, Hooke's Law & More - Garage Physics by Eisco : Industrial & Scientific
Squirrel vs Catapult Bird Feeder | Squirrels kept breaking into my "squirrel-proof" bird feeders so I had to outsmart them on my own :) | By Mark Rober | Facebook