When the power goes out and is later restored, how do you know what time to set your clocks to? Have you ever wondered how time is regulated?

In the United States, the standard of time is regulated by the US Naval Observatory's Master Clock (USNO), the official source of time for the Department of Defense. The effects of these mechanisms are felt by all of us in the f­orm of alarm clocks, computers, answering machines and meeting schedules. In this edition of HowStuffWorks, we will learn all about atomic clocks and how they keep the world ticking!

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