Critical mass is a sociodynamic term to describe the existence of sufficient momentum in a social system such that the momentum becomes self-sustaining and fuels further growth.
As a simple example, consider a big city. When one person stops and looks at the sky, nothing will happen. The other people will go after their own business. When three persons stop and look up the sky, perhaps some people will turn around, then go along. But there's only a small number (which depends on the culture, the daytime, the width of the street and other factors) of people needed -- say, 5 or 7 --, that make other ones stop and look at the sky, too. This number is called "Critical mass" or Tipping Point.
As the former is a social process, there's another one in physics. When running a nuclear reactor, you need a critical mass of nuclear material, that is, to initiate the nuclear reaction. When there's not enough material, the reaction will eventually die. While the other effects are social ones, it is possible, that these theories have been named after this physical one.
Critical mass is a concept used in a variety of contexts, including physics, group dynamics, politics, public opinion, and technology.
See also
References
- Philip Ball: Critical Mass: How One Thing Leads to Another, Farrar, Straus and Giroux, ISBN 0374530416
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