[ Kids/Teens ] - The University of Houston College of engineering, describes how an hourglass works and also provides interesting facts about this timekeeper.
[ 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.
[ 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.
[ 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.
[ Kids/Teens/Mature Teens ] - Answers questions about how an hourglass keeps time and what are the contributing factors determining how long an hourglass lasts.
[ 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.