Nuclear fission is one of the most powerful processes in nature. It occurs when a heavy atomic nucleus, such as Uranium-235, splits into two or more lighter nuclei. This process releases neutrons and an enormous amount of energy, making it the foundation of nuclear power and nuclear weapons.
The fission process occurs in three main steps. First, a neutron is absorbed by the heavy nucleus, making it unstable. Second, the unstable nucleus splits into two smaller fragments, typically barium and krypton in the case of Uranium-235. Finally, the process releases several neutrons and enormous amounts of energy in the form of kinetic energy and radiation.
A chain reaction occurs when the neutrons released from one fission event trigger additional fission events in nearby nuclei. Each fission releases multiple neutrons, which can then cause more nuclei to split. This creates an exponential multiplication effect. For a sustained chain reaction to occur, a critical mass of fissile material is required to ensure enough neutrons hit other nuclei rather than escaping.
Nuclear fission releases enormous amounts of energy according to Einstein's famous equation E equals m c squared. A tiny amount of mass is converted into energy. Just one gram of Uranium-235 releases energy equivalent to burning three tons of coal. This makes nuclear fission extremely useful for power generation, where controlled fission heats water to produce steam that drives turbines and generators to create electricity.
To summarize what we have learned about nuclear fission: It is a process where heavy atomic nuclei split into lighter fragments, releasing neutrons and enormous amounts of energy. Chain reactions occur when these neutrons trigger additional fission events, but require critical mass to be sustained. This powerful process has important applications in electricity generation and medical isotope production.