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chain reaction n.
A series of events in which each induces or influences the next.
A series of chemical reactions in which one product of a reacting set is a reactant in the following set.
A multistage nuclear reaction, especially a self-sustaining series of fissions in which the release of neutrons from the splitting of one atom leads to the splitting of others.
|chain reaction |
A process in which the result of one event triggers another event, usually of the same kind, which in turn triggers yet another event, so that the overall reaction tends to be self-sustaining. Nuclear fission reactions are chain reactions, in which the splitting of an atomic nucleus releases neutrons that penetrate other nuclei, causing them to split. The spread of heat through a substance is also a chain reaction, as fast-moving molecules in a hot part of the substance collide with neighboring molecules, passing on their kinetic energy to them, thereby making more of the substance warmer. See more at fission. See Note at nuclear reactor. See also kinetic theory.
In chemistry and physics, a self-sustaining series of reactions. In a chain reaction in a uranium-based nuclear reactor, for example, a single neutron causes the nucleus of a uranium atom to undergo fission. In the process, two or three more neutrons are released. These neutrons start more fissions, which produce more neutrons, and so on.
Note: Figuratively speaking, any group of events linked so that one is the cause of the next can be called a “chain reaction.”