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Measuring Time It is now possible to buy a watch or clock that synchronizes itself with the United States Naval Observatory. There, more than fifty clocks measure the frequency emitted by atoms of the metallic element cesium. The atomic clocks are accurate to within one second every 1,400,000 years. In fact, our ability to measure time is more accurate than the stability of the earth. A "leap second" is added to the clock most years because ocean tides are causing the earth to turn slightly slower. The first mechanical clocks in Europe had no numbers. Most people couldn't read, and the technology to create a clock face was not initially in place. Clocks would count out the hour by ringing a large bell high in a tower. The term o'clock is a contraction for "of the clock." The first mechanical clocks in Europe had no numbers. Most people couldn't read, and the technology to create a clock face was not initially in place. Clocks would count out the hour by ringing a large bell high in a tower. The term o'clock is a contraction for "of the clock." The Romans borrowed the seven-day week from the Hebrews. The week is associated with the Old Testament, where God created the world in six days and rested on the seventh. The Romans once had an eight-day week, but shortened it when they adopted Christianity. Our months correspond with the phases of the moon. A full moon occurs every 27 days, but in time we have adjusted the calendar in order make twelve months equal to the solar year. |
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