Gravity Catapult


I have long been enamored of catapults. Invented around 400 B.C., they were used until nearly A.D. 1300. So for 1,700 years, catapults were arguably the largest, most expensive, and most powerful machines on the planet. Today, people build catapults for fun: Scout troops, historical reenactors, fathers and daughters, beer-stoked... Read more »

Soda Bottle Rocket


I’ve been a big fan of model rocketry since I built my first Estes Alpha back in third grade. Nothing is more exciting to a 9 year-old proto-geek than launching a homemade rocket. But flying those one-shot solid-fuel rockets can burn a hole through a young hobbyist’s wallet faster than... Read more »