A two-part article that discusses physicist's evolving view of time.

Evolution of timekeeping through the centuries.

Calculate the exact time in days, hours, minutes and seconds from now until your birthday or any other event.

Why do we use daylight savings time and who invented it?

Article explores a clock designed to keep accurate time for 10,000 years.

Complete five-part explanation of time and how it is measured, including information about clocks, time zones, calendars, BC and AD.

Clock using video of a hand drawing to display the time.

by Markus Kuhn - An introduction to ISO 8601, the YYYY-MM-DD date and the 24-hour time notation, with notes on week numbers and on implementation.

Introduction to latitude and longitude, a way of calculating exactly where you are anyplace on earth and a way to tell time.

Learn how to tell time by finding constellations in the night sky.

Learn how to make a sundial. Instructions are for beginners, intermediate, or advanced, and work for either the northern or southern hemispheres.

Before there were clocks, people used shadows to tell time. Learn how to make your own sun clock!

Benjamin Franklin first called for the government to tinker with clock hours in the 1780s. But it wasn't until World War I that the United States adopted daylight-saving time as a way to get more efficiency out of the day. "Seize the Daylight" Author David Prerau talks about the complicated politics and curious history of DST, and he shares an excerpt from his book. [4:54 streaming audio broadcast]

Demonstrates how water clocks can be used to keep time.

Talks about how different types of atomic clocks work, and the history of their invention.

History of the clock and how Americans have measured time and been affected by it.

Describes Galileo's work on pendulums and the pendulum clock.

The University of Houston College of engineering, describes how an hourglass works and also provides interesting facts about this timekeeper.

Just how do we measure time and what has Greenwich England got to do with it?

Is time travel possible? See what Carl Sagan and Einstein had to say about time travel in this NOVA special.

Current time in tables of places in the world. Can be sorted and otherwise customized. Includes meeting planner and other time-related tools.

Answers questions about how an hourglass keeps time and what are the contributing factors determining how long an hourglass lasts.

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.

Explanation of when and why we have daylight savings time.

Provides online times converter and brief information about GMT/UTC.