shake Unit Converter

Definition of shake unit

A shake is an informal unit of time equal to 10 nanoseconds, or 10−8 seconds. It is used mainly in nuclear physics to describe extremely brief intervals, especially processes occurring during nuclear fission.

History of shake unit

The term shake emerged during the development of nuclear weapons in the 1940s. Engineers and physicists needed a convenient name for the tiny time intervals involved in neutron multiplication and chain reactions. In that context, “a few shakes” meant roughly 10 nanoseconds, comparable to the time available for one generation of neutrons in a fission event. The expression is commonly associated with informal technical language among scientists working on the Manhattan Project, although its exact individual origin is uncertain. It later appeared in nuclear engineering, physics writing, and popular scientific explanations.

Applications of shake unit

Today, the shake remains a convenient informal term in nuclear science, especially when discussing neutron generations, reactor kinetics, and fission-chain timing. For example, a process lasting 50 nanoseconds may be described as lasting five shakes. The unit also appears in educational materials and popular science, but it is not generally used for legal, commercial, or everyday timekeeping.

Complete list of shake unit conversion