A descriptive look at the history of timekeeping from ancient to modern methods, with a brief introduction to NIST Time and Frequency Services.
Originally published in 1977, this full-length book provides a comprehensive, easy-to-understand introduction to the field of time and frequency. Readers of nearly all ages and educational backgrounds should find it enjoyable. 306 pages.
Compare your computer's clock with NIST's atomic clock set to Coordinated Universal Time (UTC).
FAQ (frequently asked questions) and Glossary of Frequency and Timing.
General Interest Time and Frequency Publications
Exhibits from the Physical Measurement Laboratory
in the NIST Virtual Museum
A history of the NBS radium standards and Marie Curie's involvement.
Experiments in late 1956 demonstrating that our world is distinguishable from its mirror image.
Invention of a precursor instrument, the topografiner, between 1965 and 1971.
The modern length standard has evolved over a period of 200 years which has brought it to a point where it can be continually improved without the necessity of changing its definition.
Meter definition timeline, from 1791 to 1983.
Celebrating the 100th Anniversary of the Discovery of Superconductivity
* Links include numerous articles, official statements, congratulations, and photographs.