Bill pauses to check the time on his new atomic wristwatch.

[theweaselking]

Do not be misled. The many "atomic time" wristwatches you see on the market today are merely cheap quartz wristwatches with a built-in radio receiver. The watch sets itself from 60 kHz VLF radio time signals transmitted by NIST from station WWVB near the US atomic clock in Boulder, Colorado. At least once a day, reception permitting, usually at night, the watch resets itself to compensate for the normal drift of a quartz crystal. The result is a self-setting, radio-controlled, atomic-time, wrist watch that is never off by more than a second or two a day. Impressive and convenient. But these are not atomic clocks.

Today we have the first true atomic wristwatch.