What time is it?
How to get the time using a telephone, computer or radio signals.
NIST Radio Broadcasts
Descriptions and uses of radio signals from WWV, WWVB and WWVH.
How is UTC(NIST) related to Coordinated Universal Time (UTC). International Atomic Time (TAI), Greenwich Mean Time (GMT). USNO time, GPS time and Zulu time?
Daylight saving time rules, exceptions and legislation. Time zones, borders, abbreviations and relationship to U.S. postal zip codes.
What leap seconds are, how they are implemented and their future.
Timekeeping and Clocks
How clocks work. Cesium clocks, why we need precise time and frequency. Stopwatch calibrations, calendars and history.
Times of day
How to use a.m./p.m. vs. noon/midnight. Sunrise/sunset times and definitions of dusk/dawn/twilight.
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