Gauss Rifle

Did you know that maglev trains in Japan can reach up to 375 mph using magnets? Since magnets can carry a 350-metric-ton train, maybe I can pull it off with a 5-gram metallic marble to destroy a very annoying Minecraft creature named the creeper?

Meet the Creeper Begone 3,000 — a toy tank with a Gauss rifle. The tank itself is based off a VEX IQ drivetrain, but the shooting part is fully custom-made with 3D-printed parts of my own design. It uses metallic balls and rare-earth magnets (which apparently aren’t that rare on Amazon).

The Gauss rifle works in the following way: have you ever seen Newton’s cradle with 5 hanging metallic balls? When the first ball hits the others, the last one swings away with the same velocity. This is exactly what is happening here, but the magnets help speed up the ball, and since the construction is multi-staged, the ball accelerates slightly every time.

This project required much more trial-and-error experimentation, and most of the time, things didn’t work as I expected. I had to change and redo everything multiple times. For example, I had to change the ball size and amount per stage, magnet size, or even reprint the cannon to adjust the distance between the stages. All of that had a not-obvious effect on the outcome. Something I learned from this experience is that to achieve a great goal, you first have to achieve lots of great failures.