See also:

• Kids and Teens: School Time: Reference Tools: Calendars  (28)

• Countdown [ Kids/Teens/Mature Teens ] - Calculate the exact time in days, hours, minutes and seconds from now until your birthday or any other event.
• Daylight Saving Time [ Teens/Mature Teens ] - Why do we use daylight savings time and who invented it?
• Discover Magazine: Time Machine [ Teens/Mature Teens ] - Article explores a clock designed to keep accurate time for 10,000 years.
• The Galileo Project - Pendulum Clock [ Teens/Mature Teens ] - Describes Galileo's work on pendulums and the pendulum clock.
• A History of Time [ Teens/Mature Teens ] - A two-part article that discusses physicist's evolving view of time.
• The Hourglass [ Kids/Teens ] - The University of Houston College of engineering, describes how an hourglass works and also provides interesting facts about this timekeeper.
• How Stuff Works: Time [ Teens/Mature Teens ] - Complete five-part explanation of time and how it is measured, including information about clocks, time zones, and calendars.
• Industrious Clock [ Kids/Teens/Mature Teens ] - Clock using video of a hand drawing to display the time.
• International Standard Date and Time Notation [ Mature Teens ] - International Standard ISO 8601 specifies numeric representations of date and time. It helps to avoid confusion caused by the many different national notations.
• Latitude and Longitude [ Mature Teens ] - Introduction to latitude and longitude, a way of calculating exactly where you are anyplace on earth and a way to tell time.
• Local Times Around the World [ Teens/Mature Teens ] - Find out what time it is anywhere in the world.
• Make Your Own Star Clock [ Kids/Teens/Mature Teens ] - Learn how to tell time by finding constellations in the night sky.
• Making a Horizontal Sundial [ Teens/Mature Teens ] - Learn how to make a sundial. Instructions are for beginners, intermediate, or advanced, and work for either the northern or southern hemispheres.
• Making a Sun Clock [ Kids/Teens ] - Before there were clocks, people used shadows to tell time. Learn how to make your own sun clock!
• National Geographic Kids Magazine: Water Clock Experiment [ Kids/Teens ] - Demonstrates how water clocks can be used to keep time.
• NPR : 'Seize the Daylight' [ Teens/Mature Teens ] - Talks about the complicated politics and curious history of daylight standard time.
• On Time [ Kids/Teens/Mature Teens ] - 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.
• Science Museum - Atomic Clocks [ Teens/Mature Teens ] - Talks about how different types of atomic clocks work, and the history of their invention.
• Time [ Kids/Teens ] - Just how do we measure time and what has Greenwich England got to do with it?
• Time Travel [ Teens/Mature Teens ] - Is time travel possible? See what Carl Sagan and Einstein had to say about time travel in this NOVA special.
• US Library of Congress - How does an hourglass measure time? [ Kids/Teens/Mature Teens ] - Answers questions about how an hourglass keeps time and what are the contributing factors determining how long an hourglass lasts.
• A Walk Through Time [ Teens/Mature Teens ] - An illustrated history of timekeeping from ancient times to the present.
• What Time Is It! [ Kids/Teens/Mature Teens ] - 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.
• When Does Daylight Savings Time Occur [ Teens/Mature Teens ] - Explanation of when and why we have daylight savings time.
• World Time Converter [ Teens/Mature Teens ] - Provides online times converter and brief information about GMT/UTC.