A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place.
AMAZING Chain Reactions! by Hevesh5
In a chain reaction, positive feedback leads to a self-amplifying chain of events.
Positive feedback is a process that occurs in a feedback loop in which the effects of a small disturbance on a system include an increase in the magnitude of the perturbation.
A chain of events is a number of actions and their effects that are contiguous and linked together that results in a particular outcome.
Journey - Chain Reaction by journeyVEVO
Chain reactions are one way in which systems which are in thermodynamic non-equilibrium can release energy or increase entropy in order to reach a state of higher entropy.
Non-equilibrium thermodynamics is a branch of thermodynamics that deals with physical systems that are not in thermodynamic equilibrium but can be described in terms of variables that represent an extrapolation of the variables used to specify the system in thermodynamic equilibrium.
Thermodynamics is a branch of physics concerned with heat and temperature and their relation to energy and work.
For example, a system may not be able to reach a lower energy state by releasing energy into the environment, because it is hindered or prevented in some way from taking the path that will result in the energy release.
If a reaction results in a small energy release making way for more energy releases in an expanding chain, then the system will typically collapse explosively until much or all of the stored energy has been released.
A macroscopic metaphor for chain reactions is thus a snowball causing a larger snowball until finally an avalanche results.
This is a result of stored gravitational potential energy seeking a path of release over friction.
Chemically, the equivalent to a snow avalanche is a spark causing a forest fire.
In nuclear physics, a single stray neutron can result in a prompt critical event, which may finally be energetic enough for a nuclear reactor meltdown or a nuclear explosion.
In nuclear engineering, prompt criticality is said to be reached during a nuclear fission event if one or more of the immediate or prompt neutrons released by an atom in the event causes an additional fission event resulting in a rapid, exponential increase in the number of fission events.
The neutron is a subatomic particle, symbol n or n0, with no net electric charge and a mass slightly larger than that of a proton.