Nuclear fission facts for kids
Nuclear fission is a powerful process. It happens when a tiny atom splits into smaller pieces. This splitting releases a huge amount of energy. We use this energy in nuclear weapons and nuclear reactors.
Scientists discovered nuclear fission in December 1938. It was found by the German nuclear chemist Otto Hahn and his assistant Fritz Strassmann in Berlin.
Contents
What is an Atom?
An atom is the smallest building block of a chemical element. Think of elements like hydrogen, oxygen, or magnesium. All atoms are incredibly small.
At the very center of every atom is a tiny ball called a nucleus. Elements with very large nuclei, like uranium and plutonium, can be made to split.
How Fission Happens
When a slow-moving neutron hits a very large nucleus, that nucleus can become unstable. This means it is no longer balanced. It then breaks into two smaller nuclei.
When the nucleus breaks apart, or fissions, it releases a lot of energy. It also sends out some more neutrons.
The Chain Reaction
For some special types of atoms, one fission can release many neutrons. If these new neutrons then hit other atoms, they can make those atoms split too. This process can happen again and again.
This repeating process is called a nuclear chain-reaction. It can release huge amounts of energy very quickly. The energy released by a nuclear chain reaction is measured in units called kilotons. One kiloton is the same as the energy from one thousand tons of TNT (a powerful explosive).
Fission in Action
In a nuclear bomb, this chain reaction happens very quickly. This creates a massive explosion.
In a nuclear reactor, the chain reaction is controlled. It happens slowly to produce heat. This heat is used to boil water, making steam. The steam then spins a turbine to create electricity.
Images for kids
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A visual representation of an induced nuclear fission event where a slow-moving neutron is absorbed by the nucleus of a uranium-235 atom, which fissions into two fast-moving lighter elements (fission products) and additional neutrons. Most of the energy released is in the form of the kinetic velocities of the fission products and the neutrons.
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The stages of binary fission in a liquid drop model. Energy input deforms the nucleus into a fat "cigar" shape, then a "peanut" shape, followed by binary fission as the two lobes exceed the short-range nuclear force attraction distance, then are pushed apart and away by their electrical charge. In the liquid drop model, the two fission fragments are predicted to be the same size. The nuclear shell model allows for them to differ in size, as usually experimentally observed.
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The cooling towers of the Philippsburg Nuclear Power Plant, in Germany.
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Hahn and Meitner in 1912
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Experimental apparatus similar to that with which Otto Hahn and Fritz Strassmann discovered nuclear fission in 1938. The apparatus would not have been on the same table or in the same room.
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Drawing of the first artificial reactor, Chicago Pile-1.
See also
In Spanish: Fisión nuclear para niños
