Catapults from Ice Cream Sticks

Some lessons need a lab. This one needed a bag of ice cream sticks and a lot of rubber bands.

A catapult is physics you can feel. Pull the arm back and the bands push against your fingers. That push is energy waiting. Let go and it becomes motion. Potential to kinetic, in about a tenth of a second.

Newton's laws usually arrive as three tidy sentences. Here, they arrive as tension in your hand, a recoil through the frame, and a projectile that goes exactly as far as the forces allow and no further.

Building it came first. Sticks bound tight, an A-frame base wide enough not to tip, a launch arm, bands stretched across. Triangles everywhere, because triangles don't fold when you lean on them.

Then things broke. Bands snapped. Joints that looked solid twisted under load. In electronics, a mistake is quiet: an LED that won't light. Here, mistakes are loud. Something pings across the table and everyone looks up.

I like that about mechanical builds. Failure isn't hidden. You see exactly where the weak point was, you strengthen it, and you try again.

Once the catapults held, it turned into a contest. Which launch angle sends it furthest? Too steep and it goes up and drops close. Too flat and it hits the floor early. Somewhere in between is the sweet spot, and students found it by trying, not by being told.

The whole session cost almost nothing. That's the point I'd make to anyone who thinks science needs expensive equipment. The forces are the same whether your materials are cheap or not. Physics is free. You just have to go and pull on it.