Nuclear fission

Nuclear fission is a powerful reaction where the center of an atom splits into smaller pieces. This splitting releases a lot of energy, more than we get from fuels like coal or gas. It also gives off light energy and can create new forms of matter.

This process was first discovered in 1938 by scientists Otto Hahn and Fritz Strassmann, with help from Lise Meitner and Otto Robert Frisch. They found that when big atoms split, they can release tiny particles called neutrons. These neutrons can hit other atoms and cause a chain reaction.

We can use nuclear fission to make energy in power plants, where the reaction is controlled to produce heat and electricity. The same process, when uncontrolled, powers nuclear weapons. However, using fission also creates materials that stay dangerous for a long time, called nuclear waste, which we must handle carefully.

Physical overview

Nuclear fission is a process where the nucleus of an atom splits into two or more smaller nuclei. This splitting can happen on its own or be caused by a particle hitting the nucleus. When fission occurs, it releases a lot of energy. Most of this energy comes from the movement of the smaller nuclei created, with smaller amounts coming from other particles like neutrons and gamma rays.

Fission can sometimes happen without any outside help, as a type of natural process called spontaneous fission. When fission is caused by an outside particle, like a neutron, it can break apart in different ways. One common way fission happens is when a neutron hits a uranium-235 nucleus, causing it to split into smaller nuclei and release more neutrons. These new neutrons can then cause more fission events, leading to a chain reaction.

The energy released in fission comes from the difference in mass between the original nucleus and the smaller pieces created. The binding energy of nuclei helps decide how much energy is released. Heavier nuclei, like those of uranium, release a lot of energy when they split.

History

Discovery of nuclear fission

In 1938, scientists discovered nuclear fission. They were studying the tiny parts inside atoms, called nuclei, and noticed that they could break apart. This built on years of research about radioactivity and atoms.

Four important scientists helped make this discovery: Otto Hahn, Fritz Strassmann, Lise Meitner, and Otto Robert Frisch. They found that when uranium atoms were hit with neutrons, the nuclei could split into two smaller pieces. This process released a lot of energy and was called "nuclear fission" because it was like how living cells divide.

This discovery opened new doors in science and led to important new ways to make energy and tools for research.