In sociology, a tipping point or angle of repose is the event of a previously rare phenomenon becoming rapidly and dramatically more common. The phrase was coined in its sociological use by Morton Grodzins, by analogy with the fact in physics that adding a small amount of weight to a balanced object can cause it to suddenly and completely topple.
Grodzins studied integrating American neighborhoods in the early 1960s. He discovered that most of the white families remained in the neighborhood as long as the comparative number of black families remained very small. But, at a certain point, when "one too many" black families arrived, the remaining white families would move out en masse in a process known as white flight. He called that moment the "tipping point". The idea was expanded and built upon by Nobel Prize-winner Thomas Schelling in 1972. A similar idea underlies Mark Granovetter's threshold model of collective behavior.
Mathematically, the angle of repose may be seen as an inflection point. In control theory, the concept of positive feedback describes the same phenomenon, with the problem of balancing an inverted pendulum being the classic embodiment. The concept has also been applied to the popular acceptance of new technologies, for example being used to explain the success of VHS over Betamax.