 About time  Keith Devlin (Devlin's Angle)
An essay on time in mathematics and engineering (the time that we measure and use to regulate our lives). How did we come to measure time in the first place? What exactly is it that our timepieces measure? And what scientific principles do we use to construct ever more accurate clocks?
more>>
 Algebra  Fun with Calendars  Cynthia Lanius
Take any calendar. Tell a friend to choose 4 days that form a square. If your friend tells you only the sum of the four days, you can tell her what the four days are. How does the puzzle work? Includes a extension page for designing your own puzzle, teachers notes, and links to calendar pages on the Web. Mathematics topics: assigning variables, solving simple linear equations, factoring.
more>>
 The Calendar and the Days of the Week  Math Forum, Ask Dr. Math FAQ
What years are leap years? What day of the week will it be a year from today? How do I find the day of the week for any date? How do I find a calendar for any year? How common are Friday the 13ths?
more>>
 Calendars and Astronomy (Math and the Heavens)  Dave Rusin, The Mathematical Atlas
Moreorless mathematical posts related to calendars and astronomy: background information on calendar traditions and a discussion of the mathematical aspects of the calendar, with a pointer to the Calendar FAQ; the related questions, on which day of the week does a date fall? and when's Easter this year?; and sources of astronomical data.
more>>
 Clockworks: From Sundials to the Atomic Second  Britannica.com
A site about the development of instruments that have measured time over the centuries. Each instrument has a page featuring a description and an illustrated diagram, and most include a QuickTime animation demonstrating how the mechanism works. Iinstruments include: Sundial; Clepsydra; Astrolabe; Candle clock; Sandglass; Weightdriven clock; Springdriven clock; Pendulum clock; Quartz watch; Cesium atomic clock. See also the article "Measuring Time."
more>>
 Horology: The Index  Fortunat MuellerMaerki
Internet resources on clocks and time: directories, dictionaries, glossaries, etc.; organizations, information sources (horological homepages; email addresses for cyber horologists; other electronic media: newsgroups, directories, ezines, mail lists, bulletin boards; periodicals; libraries and documentation centers; books: publishers, sellers, book lists, bibliographies, reviews); timepieces; subjects, issues, and topics in horology; and ways of finding and setting the exact time, including time zones and a time zone converter.
more>>
 Time for Time  Darren Dalasta
For teaching the concept of time and how to tell time. Includes games, quizzes, and an interactive class clock for students; lesson plans and worksheets for teachers; history of telling time, U.S. time zones, world time zones.
more>>
 World Time Zone  iSBiSTER International, Inc.
The exact time in world countries from Afghanistan to Zimbabwe, including, individually, the United States and the Canadian provinces. A software Time Zone Map program that does not require an active connection to the Internet is also available from this site.
more>>
 
