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watch |
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watch, small, portable timepiece usually designed to be worn on the person. Other kinds of timepieces are generally referred to as clocks clock, instrument for measuring and indicating time. Predecessors of the clock were the sundial , the hourglass , and the clepsydra . See also watch .
The Evolution of Mechanical Clocks..... Click the link for more information. . At one time it was generally believed that the first watches were made in Nuremburg, Germany, c.1500. However, there is now evidence that watches may have appeared at an earlier date in Italy. Early watches were ornate, very heavy, and made in a variety of shapes, e.g., pears, skulls, and crosses; the faces were protected by metal latticework. Watch parts were made by hand until c.1850, when machine methods were introduced by watch manufacturers in the United States. The introduction of machine-made parts not only cut manufacturing costs but increased precision and facilitated repairs. To insure the accuracy of a watch over a long period, bearings made of jewels (usually synthetic sapphires or rubies) are utilized at points subject to heavy wear. The mechanical watch contains a mainspring to drive the watch's mechanism. Part of the mechanism includes a hairspring and an oscillating balance wheel to control the rate at which the mechanism moves. The mainspring is wound by the wearer when he turns a knob outside the watch's casing. The automatic, or self-winding, watch has a mainspring that is wound by an oscillating weight, contained in the watch, that is set into motion by the movements of the wearer. The stopwatch can be stopped or started at will by pressing a tiny button on its edge and is used for timing such events as races. The electric watch, which was introduced by the Hamilton Watch Company in 1957, also uses a hairspring and a balance wheel to regulate the rate at which its mechanism moves, but it has no mainspring. In recent years sophisticated electronic watches have been developed. One type uses the vibrations of an electrically driven tuning fork to determine the rate at which a small motor drives the hands. In another type a crystal oscillator provides a signal that regulates this motion. In the most common type a quartz crystal oscillator is joined to digital counting and digital display circuits, thus eliminating all moving parts. See liquid crystal liquid crystal, liquid whose component particles, atoms or molecules, tend to arrange themselves with a degree of order far exceeding that found in ordinary liquids and approaching that of solid crystals. ..... Click the link for more information. . Quartz watches with digital displays now account for nearly half of all watch production, since they are inexpensive to produce but are accurate to within several seconds per month. Electric and electronic watches are powered by tiny long-lasting batteries. See chronometer chronometer (krənŏm`ətər), instrument for keeping highly accurate time, used especially in navigation. ..... Click the link for more information. . BibliographySee C. Clutton and G. Daniels, Watches: A Complete History (3d ed. 1979); J. Zagoory and H. Chan, A Time to Watch: The Wrist Watch as Art (1985); E. Bruton, History of Clocks and Watches (1989). watchPortable timepiece designed to be worn on the wrist or carried in the pocket. The first watches appeared shortly after 1500, when the mainspring (see spring) was invented as a replacement for weights in driving clocks. The progressive miniaturization of electronic components in recent decades has made possible the development of all-electronic watches, in which the necessary transistors, resistors, capacitors, and other elements are all on one or several miniature integrated circuits, or chips. Such circuitry enables them to perform several timekeeping functions and also makes possible digital readouts of the time. watch Nautical a. any of the usually four-hour periods beginning at midnight and again at noon during which part of a ship's crew are on duty b. those officers and crew on duty during a specified watch watch [wäch] (communications) The service performed by a qualified operator when on duty in the radio room of a vessel. Also known as radio watch. (horology) A small timepiece of a size convenient to be carried on the person. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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When he takes the field for the first time, Hart fans watching back in Santa Clarita will see a much different player than they might remember. The dreams of an entire hockey-mad nation were realized Sunday afternoon when Canada overcame harsh criticism and its own crushing expectations to defeat the United States 5-2 in front of a crowd of 8,599 at the E Center and tens of millions watching back home. |
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