Critical mass (sociodynamics)

In social dynamics, critical mass is a sufficient number of adopters of an innovation in a social system so that the rate of adoption becomes self-sustaining and creates further growth. It is an aspect of the theory of diffusion of innovations, written extensively on by Everett Rogers in his book Diffusion of Innovations. The term is borrowed from nuclear physics and in that field it refers to the amount of a substance needed to start a chain reaction.