What are Atomic Clocks?

At the dawn of the 'Space Age' the scientific community needed to measure time in tiny fractions of a second. They determined that one second is as long as 9,192,631,770 oscillations of the Cesium 133 atom. Because the characteristics of Cesium 133 are so stable it is the best substance to use for determining this standard. In several places around the world, 'Atomic' clocks using Cesium 133 are in operation giving us the exact time as a reference for everyone to use. The National Institutes of Standards and Technology operates an atomic clock in Colorado and its time is broadcast throughout North America using long-range radio technology. (You may listen to radio station WWV for time and other voice announcements using standard, shortwave radios). This information is used by scientists who are running sophisticated experiments and it is used by airlines, schools, and others who need to have the exact, correct time as a standard for everyone to use. Radio station WWVB is the source by which all these radio controlled clocks receive the time in North America.

What is a "Radio Controlled" Clock?

There are several kinds of clocks with built-in radio receivers which can access atomic time data from those radio broadcasts. These clocks then set themselves automatically to the correct time... right down to fractions of a second! In the mid-1990s, such clocks became available on the consumer level. Initially, they were highly priced but as technology improved, manufacturing improved, and market competition heated up, these clocks have come down in price and the variety of styles has also increased. You may now have an affordable clock in your home or office which will automatically set itself to the exact, correct time. The vast majority of these clocks also adjust themselves automatically for Daylight Saving Time. Most will run for at least 2 years on a normal, alkaline battery, making them very convenient. If you're accustomed to taking your clocks off the wall at least twice each year to change batteries or to adjust for Daylight Saving Time, this can now be a thing of the past. With a radio controlled clock, you put in the battery and the clock does the rest!