Get smarter in sixty seconds with brain Stuff from how stuffworks dot com Hi Marshall Brain. Atomic clocks are important to a variety of scientific endeavors. You can even buy wall clocks and wrist watches that will synchronize with an atomic clock in Colorado. So what exactly is an atomic clock. Let's start with the general notion of a clock. A clock's job is to keep track of the passage of time. All clocks do this by counting the ticks of some
kind of resonator. In a pendulum clock, the resonator is the pendulum. The gears in the clock keep track of the time by counting the resonations, those swingings back and forth of the pendulum. The pendulum usually resonates at a frequency of one swing per second. A digital clock uses either the oscillations of the power line, which is sixty cycles per second in the United States, or the oscillations of a quartz crystal as the resonator. It counts the
oscillations using digital counters. The accuracy the clock is determined by the accuracy of the resonator. In an atomic clock, the clock uses the resonant frequency of atoms as its resonator. There are many different ways to get atoms to oscillate, and you can then detect and count those oscillations. The advantage of this approach is that the atoms resonate at
extremely consistent frequencies. If you take any atom of caesium and ask it to resonate, for example, it will resonate at exactly the same frequency as any other atom of caesium. Caesium one thirty three oscillates at nine billion, one nine two million, six hundred thirty one thousand, seven hundred seventy cycles per second period. This sort of accuracy is completely different from the accuracy of a Courts clock. In a quartz clock, the Courts crystal is manufact extured so that
it's oscillating frequency is close to some standard frequency. But manufacturing tolerances cause every crystal to be slightly different, and things like temperature will change the frequency. A caesium atom will always resonate at the same known frequency. That is what makes atomic clock so precise. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com.
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