Recently, I ran across a video from NHK World about a competition between two Japanese teams to see who could build a small top that could spin the longest. In the competition, the top must spin on a pedestal just 2 cm in diameter. The physics, mathematics, engineering, machining and material research are phenomenal to watch. Each top must have a diameter of 5 cm or less and weigh 500 grams or less. Each team was allowed one month to design and fabricate. While the translation from Japanese into English is stilted, the engineering itself is not. Amazing stuff.
Check It Out: Can You Build a "Toy" Top That Spins Forever?