Shake ( unit ) - Wikipedia Shake ( unit ) A shake is an informal unit of time equal to 10 nanoseconds, or 10 seconds. It has applications in nuclear physics, helping to conveniently express the timing of various events in a nuclear explosion. The typical time required for one step in the chain reaction ( i.e. the typical time for each neutron to cause a fission event, which releases more neutrons ) is of the order of 1 shake, and the chain reaction is typically complete by 50 to 100 shakes. This is also applicable to circuits. Since signal progression in IC chips is very rapid, on the order of nanoseconds, a shake is good measure of how quickly a signal can progress through an IC ( integrated circuit ). Like many nuclear units, it is derived from top secret operations of the Manhattan Project during World War II. The word comes from the expression `` two shakes of a lamb 's tail '' or, in the Southern United States, `` three shakes of a billy - goat 's tail, '' which indicates a very short time interval. For nuclear - bomb designers, 10 nanoseconds was a convenient specific interval to connect to this term. It has been discussed at length that the oldest documented usage of the phrase `` two shakes of a lamb 's tail '' can be found within the compiled works of Richard Harris Barham called The Ingoldsby Legends. References Jump up ^ `` Definition '' University of North Carolina at Chapel Hill website Jump up ^ http://web.archive.org/web/20081206163819id_/http://docs.nrdc.org/nuclear/files/nuc_04109401a_122.pdf Jump up ^ `` Two Shakes of a Lamb 's Tail ''. Retrieved 28 June 2012. Time measurement and standards Chronometry Orders of magnitude Metrology International standards Coordinated Universal Time offset UT ΔT DUT1 International Earth Rotation and Reference Systems Service ISO 31 - 1 ISO 8601 International Atomic Time 6 - hour clock 12 - hour clock 24 - hour clock Barycentric Coordinate Time Barycentric Dynamical Time Civil time Daylight saving time Geocentric Coordinate Time International Date Line Leap second Solar time Terrestrial Time Time zone 180th meridian Obsolete standards Ephemeris time Greenwich Mean Time Prime meridian Time in physics Absolute time and space Spacetime Chronon Continuous signal Coordinate time Cosmological decade Discrete time and continuous time Planck time Proper time Theory of relativity Time dilation Gravitational time dilation Time domain Time translation symmetry T - symmetry Horology Clock Astrarium Atomic clock Complication History of timekeeping devices Hourglass Marine chronometer Marine sandglass Radio clock Watch Water clock Sundial Dialing scales Equation of time History of sundials Sundial markup schema Calendar Astronomical Dominical letter Epact Equinox Gregorian Hebrew Hindu Intercalation Islamic Julian Leap year Lunar Lunisolar Solar Solstice Tropical year Weekday determination Weekday names Archaeology and geology Chronological dating Geologic time scale International Commission on Stratigraphy Astronomical chronology Galactic year Nuclear timescale Precession Sidereal time Other units of time Shake Jiffy Second Minute Moment Hour Day Week Fortnight Month Year Lustrum Decade Century Saeculum Millennium Related topics Chronology Duration music Mental chronometry Metric time System time Time value of money Timekeeper This physics - related article is a stub. You can help Wikipedia by expanding it. Retrieved from `` https://en.wikipedia.org/w/index.php?title=Shake_(unit)&oldid=799430963 '' Categories : Units of time Physics stubs Talk About Wikipedia Deutsch 日本 語 Русский Edit links This page was last edited on 7 September 2017, at 17 : 59. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: where did two shakes of a lamb's tail come from
Answer: the compiled works of Richard Harris Barham called The Ingoldsby Legends