A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. It is a self-amplifying chain of events.

• The neutron-fission chain reaction: a neutron plus a fissionable atom causes a fission resulting in a larger number of neutrons than was consumed in the initial reaction.
• Chemical example, every step of H₂ + Cl₂ chain reaction consumes one molecule of H₂ or Cl₂, one free radical H· or Cl· producing one HCl molecule and another free radical.
• Electron avalanche process: Collisions of free electrons in a strong electric field forming "new" electrons to undergo the same process in successive cycles.

See also

• Nuclear chain reaction
• Polymerase chain reaction
• Markov chain
• Rube Goldberg machine
• Causality
• Butterfly effect
• Thermal runaway
• Cascading failure

References

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