Time

Countdown
Calculate the exact time in days, hours, minutes and seconds from now until your birthday or any other event.
http://www.spiders.com/portfolio/demos/countdown/

Daylight Saving Time
Why do we use daylight savings time and who invented it?
http://www.mrdowling.com/601-daylight.html

Discover Magazine: Time Machine
Article explores a clock designed to keep accurate time for 10,000 years.
http://discovermagazine.com/2005/nov/cover

The Galileo Project - Pendulum Clock
Describes Galileo's work on pendulums and the pendulum clock.
http://galileo.rice.edu/sci/instruments/pendulum.html

A History of Time
A two-part article that discusses physicist's evolving view of time.
http://www-history.mcs.st-andrews.ac.uk/HistTopics/Time_1.html

The Hourglass
The University of Houston College of engineering, describes how an hourglass works and also provides interesting facts about this timekeeper.
http://www.uh.edu/engines/epi1469.htm

How Stuff Works: Time
Complete five-part explanation of time and how it is measured, including information about clocks, time zones, and calendars.
http://www.howstuffworks.com/time.htm

Industrious Clock
Clock using video of a hand drawing to display the time.
http://yugop.com/ver3/stuff/03/fla.html

International Standard Date and Time Notation
International Standard ISO 8601 specifies numeric representations of date and time. It helps to avoid confusion caused by the many different national notations.
http://www.cl.cam.ac.uk/~mgk25/iso-time.html

Latitude and Longitude
Introduction to latitude and longitude, a way of calculating exactly where you are anyplace on earth and a way to tell time.
http://www-spof.gsfc.nasa.gov/stargaze/Slatlong.htm

Local Times Around the World
Find out what time it is anywhere in the world.
http://www.timeanddate.com/worldclock/

Make Your Own Star Clock
Learn how to tell time by finding constellations in the night sky.
http://www.lhs.berkeley.edu/StarClock/starclockprintout.html

Making a Horizontal Sundial
Learn how to make a sundial. Instructions are for beginners, intermediate, or advanced, and work for either the northern or southern hemispheres.
http://www.lmsal.com/YPOP/Classroom/Lessons/Sundials/sundials.html

Making a Sun Clock
Before there were clocks, people used shadows to tell time. Learn how to make your own sun clock!
http://www.exploratorium.edu/science_explorer/sunclock.html

National Geographic Kids Magazine: Water Clock Experiment
Demonstrates how water clocks can be used to keep time.
http://www.nationalgeographic.com/ngkids/trythis/try10.html

NPR : 'Seize the Daylight'
Talks about the complicated politics and curious history of daylight standard time.
http://www.npr.org/templates/story/story.php?storyId=4572036

On Time
Learn about the history of time measuring devices in this online Smithsonian Institute exhibit. Page discusses how the accuracy of watches and clocks affected people's perception and usage of time.
http://americanhistory.si.edu/ontime/

Science Museum - Atomic Clocks
Talks about how different types of atomic clocks work, and the history of their invention.
http://www.sciencemuseum.org.uk/onlinestuff/stories/atomic_clocks.aspx

Time
Just how do we measure time and what has Greenwich England got to do with it?
http://www.mrdowling.com/601-time.html

Time Travel
Is time travel possible? See what Carl Sagan and Einstein had to say about time travel in this NOVA special.
http://www.pbs.org/wgbh/nova/time/

US Library of Congress - How does an hourglass measure time?
Answers questions about how an hourglass keeps time and what are the contributing factors determining how long an hourglass lasts.
http://www.loc.gov/rr/scitech/mysteries/hourglass.html

A Walk Through Time
An illustrated history of timekeeping from ancient times to the present.
http://physics.nist.gov/GenInt/Time/time.html

What Time Is It!
Gives the current time, synchronized by NIST. Close to 100 different time zones supported, as well as the ability to select the default time zone.
http://www.whattimeisit.com/

When Does Daylight Savings Time Occur
Explanation of when and why we have daylight savings time.
http://www.logan.ws/articles/when_does_daylight_savings_time_occur.asp

World Time Converter
Provides online times converter and brief information about GMT/UTC.
http://www.gkindia.com/bitsol_time/