The┬аhistory of timekeeping devices┬аdates back to when ancient civilizations first observed┬аastronomical bodies┬аas they moved across the sky. Devices and methods for keeping time have since then improved through a long series of new inventions and ideas.┬аSundials┬аand┬аwater clocks┬аoriginated from┬аancient Egypt, and were later used by the┬аBabylonians, the┬аGreeks┬аand the┬аChinese; medieval Islamic water clocks were unrivalled in their sophistication until the mid-14th┬аcentury.┬аIncense┬аclocks, which may have been invented in India, were being used in China by the 6th┬аcentury. The┬аhourglass, one of the few reliable methods of measuring time at sea, was a European invention and does not seem to have been used in China before the mid-16th┬аcentury.
In medieval Europe, purely mechanical clocks were developed after the invention of the bell-striking alarm, used to warn a man to toll the┬аmonastic┬аbell. The weight-driven mechanical clock, controlled by the action of a┬аverge and foliot, was a synthesis of earlier ideas derived from European and Islamic science, and one of the most important inventions in the history of the timekeeping. The most famous mechanical clock was designed and built by┬аHenry de Vick┬аin┬аc.1360тАФfor the next 300 years, all the improvements in timekeeping were essentially developments based on it. The invention of the┬аmainspring┬аin the early 15th┬аcentury allowed small clocks to be built for the first time.
From the 17th┬аcentury, the discovery that clocks could be controlled by┬аharmonic oscillators┬аled to the most productive era in the history of timekeeping.┬аLeonardo da Vinci┬аhad produced the earliest known drawings of a┬аpendulum┬аin 1493тАУ1494, and in 1582┬аGalileo Galilei┬аhad investigated the regular swing of the pendulum, discovering that┬аfrequency┬аwas only dependent on length. The┬аpendulum clock, designed and built by Dutch polymath┬аChristiaan Huygens┬аin 1656, was so much more accurate than other kinds of mechanical timekeepers that few clocks have survived with their verge and foliot mechanisms intact. Other innovations in timekeeping during this period include inventions for striking clocks, the┬аrepeating clock┬аand the┬аdeadbeat escapement. Errors in early pendulum clocks were eclipsed by those caused by temperature variation, a problem tackled during the 18th┬аcentury by the English clockmakers┬аJohn Harrison┬аand┬аGeorge Graham; only the invention of┬аinvar┬аin 1895 eliminated the need for such innovations.
From the 18th┬аcentury, a succession of innovations and inventions led to timekeeping devices becoming increasingly accurate. Following the┬аScilly naval disaster of 1707, after which governments offered a┬аprize┬аto anyone who could discover a way to determine longitude, Harrison built a succession of accurate timepieces. The electric clock, invented in 1840, was used to control the most accurate pendulum clocks until the 1940s, when quartz timers became the basis for the precise measurement of time and frequency. The wristwatch, which had been recognised as a valuable military tool during the┬аBoer War, became a symbol of masculinity and bravado after World War I. During the 20th┬аcentury the non-magnetic┬аwristwatch, battery-driven watches, the quartz wristwatch, and┬аtransistors┬аand plastic parts were all invented. The most accurate timekeeping devices in practical use today are┬аatomic clocks, which can be accurate to within a few billionths of a second per year. They are used to calibrate other clocks and timekeeping instruments.
A┬аclock┬аor a┬аtimepieceis a device used to┬аmeasure┬аand indicate┬аtime. The clock is one of the oldest┬аhuman inventions, meeting the need to measure intervals of time shorter than the natural units: the┬аday, the┬аlunar month,┬аyear┬аand┬аgalactic year. Devices operating on several physical processes have been used over the┬аmillennia.
Some predecessors to the modern clock may be considered as “clocks” that are based on movement in nature: A┬аsundial┬аshows the time by displaying the position of a shadow on a flat surface. There is a range of duration timers, a well-known example being the┬аhourglass.┬аWater clocks, along with the sundials, are possibly the oldest time-measuring instruments. A major advance occurred with the invention of the┬аverge escapement, which made possible the first mechanical clocks around 1300 in Europe, which kept time with oscillating timekeepers like┬аbalance wheels.
Traditionally, in┬аhorology, the term┬аclock┬аwas used for a┬аstriking clock, while a clock that did not strike the hours audibly was called a timepiece. This distinction is no longer made.┬аWatches┬аand other timepieces that can be carried on one’s person are usually not referred to as clocks.┬аSpring-driven clocks appeared during the 15th century. During the 15th and 16th centuries,┬аclockmaking┬аflourished. The next development in accuracy occurred after 1656 with the invention of the┬аpendulum clock┬аby┬аChristiaan Huygens. A major stimulus to improving the accuracy and reliability of clocks was the importance of precise time-keeping for navigation. The mechanism of a timepiece with a series of gears driven by a spring or weights is referred to as┬аclockwork; the term is used by extension for a similar mechanism not used in a timepiece. The┬аelectric clock┬аwas patented in 1840, and electronic clocks were introduced in the 20th century, becoming widespread with the development of small battery-powered┬аsemiconductor devices.
The timekeeping element in every modern clock is a┬аharmonic oscillator, a physical object (resonator) that vibrates or oscillates at a particular frequency.┬аThis object can be a┬аpendulum, a┬аtuning fork, a┬аquartz crystal, or the vibration of┬аelectrons┬аin┬аatoms┬аas they emit┬аmicrowaves.
Clocks have different ways of displaying the time. The History of The First Clock Analog clocks indicate time with a traditional clock face, with moving hands. Digital clocks display a numeric representation of time. Two numbering systems are in use:┬а24-hour time┬аnotation and┬а12-hour┬аnotation. Most digital clocks use electronic mechanisms and┬аLCD,┬аLED, or┬аVFD┬аdisplays. For the blind and for use over telephones,┬аspeaking clocks┬аstate the time audibly in words. The History of The First Clock There are also clocks for the blind that have displays that can be read by touch. The study of timekeeping is known as horology.