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 »

Berto’s Amphi-Cycle

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  • 12/18/2012 @ 11:00 pm

This is a low-tech project, so no welding or big machinery is needed. Everyone can use his or her own bicycle and make it amphibious. The conversion time from land to water is not more than 7 minutes; the same for the opposite direction. The design is usable for any... Read more »

Simple Van de Graaff Generator

When I was younger, I spent hours perusing Bill Beaty’s electrostatics web pages. At the time, I didn’t achieve any real successes trying to build his high-voltage contraptions, and so my interest waned. Years later, I saw someone online use a soda can as a collector for their Van de... Read more »