| |
Splitting Up
Fission is the splitting of a uranium atom (or any atom). Uranium has an atomic mass of 235 amu (atomic mass units) normally. In a nuclear reaction, scientists shoot a whole bunch of neutrons at the uranium atom. When one neutron hits the nucleus, the uranium becomes U-236. When it becomes 236, the uranium atom wants to split apart. After it splits, it gives off three neutrons. Those neutrons hit other U atoms in the area and cause them to become U-236. Once all of these neutrons start to bounce around the container, a chain reaction begins. Then the space is flooded with neutrons and huge amounts of energy.
Fizz vs. Fuse
When we were kids we always got fusion and fission confused. The confusion wasn't because the processes were similar; the words were just similar. You need to remember that one process is a breaking down process and the other is a process of building up. When things fuse (fusion), you start with smaller objects (tritium, deuterium) and build larger objects (helium). When things "fiss" or break down, you start with a larger object (uranium) and finish with a smaller object (plutonium).
Isotope Action
Why are the atoms radioactive? There is another isotope of uranium with the number 238. When one of those free neutrons hits a 238, it will bump it up to 239 (that just makes sense). But that 239 is radioactive and releases a beta particle when it decays. It's not over. That U-239 breaks down into neptunium-239. The neptunium is also radioactive. It will release another beta particle when it breaks down into plutonium-239. The plutonium will eventually give off an alpha particle (not as strong as beta, but it will kill your cells). That's a lot of particles being given off.
Einstein's Legacy
The fission process, however radioactive it is, is the main reaction that happens in many nuclear devices. It all started with Einstein's equation E=mc2. Once scientists thought there were huge amounts of energy available in each atom of the universe. That idea was used by the military to develop weapons that had enormous destructive abilities. Usually uranium or plutonium is in the bomb and a smaller explosion of material that surrounds the uranium and plutonium sets off the fission reaction. They have even developed fusion bombs that are set off by a fission reaction.
|
|
|
Go for site help or list of physics topics at the site map!