National Institute of Standards and Technology (NIST)
Nist Physics Laboratory: A Walk Through Time
An illustrated history of timekeeping from ancient times to the present. Includes information on ancient calendars, early clocks, a revolution in timekeeping, world time scales and time zones, and the NIST standards.
The Franklin Institute
The Franklin Institute: Clocks Teaching Time
This site from The Franklin Institute presents a number of activities, games, exhibits, scavenger hunts, resources, links related to clocks and telling time.
NumberNut
Number Nut: Calendar Origins
History and mathematics merge in this lesson that explores the origin of the calendar. Learn how it all got started in this detailed lesson that includes a simple months of the year game and a more challenging time conversion game. Both...