critical mass

Definitions

1. 1

   The minimum amount of fissile material needed to support a self-sustaining nuclear chain…

   The minimum amount of fissile material needed to support a self-sustaining nuclear chain reaction.

   • […] Rhodes calculated the uranium bomb would eventually need “about 42 kilograms – 92.6 pounds,” which Rhodes then stated was approximately 2.8 critical masses. In other words, critical mass can be calculated to be about 15 kilograms.
2. 2

   The minimum amount of something or the minimum number of people needed to trigger a…

   The minimum amount of something or the minimum number of people needed to trigger a phenomenon.

   • […] depending on the rare circumstance of there being a critical mass of persons whose combination of interests and resources is high enough to overcome the feasibility problem.
   • The critical mass comprises the pioneers of an SNS who pay the start-up costs and set up a circle of acquaintances for newcomers; thereafter new subscribers to a mature SNS can join one after another rather than as a group (Heijden, 2004).
3. 3

   A direct action event in which bicycle riders travel through city streets as a group.

The neighborhood

• neighborsubcritical mass
• neighborsupercritical mass
• neighbortipping point