From dinosaurs to asteroids (and meteorites) to elements. Uranium-238, my favorite. I have a small elements collection and part of it is U-238. Uranium will convert into other elements and end its life as lead. Uranium-235 is the bomb grade type and the way this 'bad boy' breaks up into energy is awesome. Me on the weekends: An Atom Bomb: A Hydrogen Bomb: 'Ivy Mike' was the codename given to the first full-scale test of a thermonuclear device, in which part of the explosive yield comes from nuclear fusion. It uses a Nagasaki style Plutonium fission bomb to set things off. Date: November, 1952 Yield: 10.4 megatons Fusion process time: 1/1,000,000 of a second.