• Danish: se efter, holde øje med
• Finnish: vahtia
• Greek: προσέχω
• Hungarian: figyel, vigyáz -ra/-re
• Irish: fair
• Italian: tenere d'occhio, sorvegliare, vigilare
• Japanese: 見守る (みまもる, mimamoru), 見張る (みはる, miharu)
• Malayalam: കാവല്‍ നില്‍ക്കുക (kaaval nilkkuka)
• Spanish: vigilar

• Danish: holde øje med, vogte på
• Finnish: olla varuillaan
• Greek: προσέχω
• Hungarian: vigyáz -ra/-re
• Italian: tenere d'occhio, stare attento a
• Japanese: 見張る (みはる, miharu)
• Romanian: avea grijă, veghea
• Russian: следить
• Spanish: tener cuidado
• Swedish: ta sig i akt, vara försiktig

• ttbc Afrikaans: kyk, dophou
• ttbc Arabic: (rá:qaba)
• ttbc Breton: sellet ouzh
• ttbc Bulgarian: гледам (gledam)
• ttbc Chinese: 觀看, 观看 (guānkàn)
• ttbc Latin: spectare
• ttbc Swahili: kuangalia
• ttbc Telugu: గమనించు (gamaniMcu)

See also

• wait
• wake

A watch is a timepiece that is made to be worn on a person, as opposed to a clock which is not. The term now usually refers to a wristwatch, which is worn on the wrist with a strap or bracelet. In addition to the time, modern watches often display the day, date, month and year, and electronic watches may have many other functions.

Most inexpensive and medium-priced watches used mainly for timekeeping are electronic watches with quartz movements. Expensive, collectible watches valued more for their workmanship and aesthetic appeal than for simple timekeeping, often have purely mechanical movements and are powered by springs, even though mechanical movements are less accurate than more affordable quartz movements.

Before the inexpensive miniaturization that became possible in the 20th century, most watches were pocket watches, which had covers and were carried in a pocket and attached to a watch chain or watch fob. Watches evolved in the 1600s from spring powered clocks, which appeared in the 1400s.

Parts

Movement

A Movement in watchmaking is the mechanism that measures the passage of time and displays the current time (and possibly other information including date, month and day). Movements may be entirely mechanical, entirely electronic (potentially with no moving parts), or a blend of the two. Most watches intended mainly for timekeeping today have electronic movements, with mechanical hands on the face of the watch indicating the time.

Mechanical movements

Main article Mechanical watch.

See also Self-winding watch, Mechanism (horology).

A self-winding or automatic mechanism is one that rewinds the mainspring of a mechanical movement by the natural motions of the wearer's body. The first self-winding mechanism, for pocketwatches, was invented in 1770 by Abraham-Louis Breguet; but the first "self-winding," or "automatic," wristwatch was the invention of a British watch repairer named John Harwood in 1923. This type of watch allows for a constant winding without special action from the wearer: it works by an eccentric weight, called a winding rotor, that rotates with the movement of the wearer's wrist. The back-and-forth motion of the winding rotor couples to a ratchet to automatically wind the mainspring. Self winding watches usually can also be wound manually so they can be kept running when not worn, or if the wearer's wrist motions don't keep the watch wound.

Some electronic watches are also powered by the movement of the wearer of the watch. Kinetic powered quartz watches make use of the motion of the wearer's arm turning a rotating weight, which turns a generator to supply power to charge a rechargeable battery that runs the watch. The concept is similar to that of self-winding spring movements, except that electrical power is generated instead of mechanical spring tension.

Electronic watches require electricity as a power source. Some mechanical movements and hybrid electronic-mechanical movements also require electricity. Usually the electricity is provided by a replaceable battery. The first use of electrical power in watches was as substitute for the mainspring, in order to remove the need for winding. The first electrically-powered watch, the Hamilton Electric 500, was released in 1957 by the Hamilton Watch Company of Lancaster, Pennsylvania.

Watch batteries (strictly speaking cells) are specially designed for their purpose. They are very small and provide tiny amounts of power continuously for very long periods (several years or more). In most cases, replacing the battery requires a trip to a watch-repair shop or watch dealer; this is especially true for watches that are designed to be water-resistant, as special tools and procedures are required to ensure that the watch remains water-resistant after battery replacement. Silver-oxide and lithium batteries are popular today; mercury batteries, formerly quite common, are no longer used, for environmental reasons. Cheap batteries may be alkaline, of the same size as silver-oxide but providing shorter life. Rechargeable batteries are used in some solar powered watches.

Some electronic watches are powered by light. A photovoltaic cell on the face (dial) of the watch converts light to electricity, which in turn is used to charge a rechargeable battery or capacitor. The movement of the watch draws its power from the rechargeable battery or capacitor. As long as the watch is regularly exposed to fairly strong light (such as sunlight), it never needs battery replacement, and some models need only a few minutes of sunlight to provide weeks of energy (as in the Citizen Eco-Drive).

Some of the early solar watches of the 1970s had innovative and unique designs to accommodate the array of solar cells needed to power them (Synchronar, Nepro, Sicura and some models by Cristalonic, Alba, Seiko and Citizen). As the decades progressed and the efficiency of the solar cells increased while the power requirements of the movement and display decreased, solar watches began to be designed to look like other conventional watches. A rarely used power source is the temperature difference between the wearer's arm and the surrounding environment (as applied in the Citizen Eco-Drive Thermo).

Display

Analog

Traditionally, watches have displayed the time in analog form, with a numbered dial upon which are mounted at least a rotating hour hand and a longer, rotating minute hand. Many watches also incorporate a third hand that shows the current second of the current minute. Watches powered by quartz have second hands that snap every second to the next marker. Watches powered by a mechanical movement have a "sweep second hand", the name deriving from its uninterrupted smooth (sweeping) movement across the markers, although this is actually a misnomer; the hand merely moves in smaller steps, typically 1/6 of a second, corresponding to the beat of the balance wheel. All of the hands are normally mechanical, physically rotating on the dial, although a few watches have been produced with “hands” that are simulated by a liquid-crystal display.

Analog display of the time is nearly universal in watches sold as jewelry or collectibles, and in these watches, the range of different styles of hands, numbers, and other aspects of the analog dial is very broad. In watches sold for timekeeping, analog display remains very popular, as many people find it easier to read than digital display; but in timekeeping watches the emphasis is on clarity and accurate reading of the time under all conditions (clearly marked digits, easily visible hands, large watch faces, etc.). They are specifically designed for the left wrist with the stem (the knob used for changing the time) on the right side of the watch, this makes it easy to change the time without removing the watch from the hand.

Analog watches, as well as clocks, are often marketed showing a display time of approximately 10:09. This creates a visually pleasing smile-like face on upper half of the watch. Digital displays often show a time of 12:38, where the increases in the numbers from left to right culminating in the fully-lit numerical display of the 8 also gives a positive feeling.

Digital

Since the advent of electronic watches that incorporate small computers, digital displays have also been available. A digital display simply shows the time as a number, e.g., 12:40 AM instead of a short hand pointing towards the number 12 and a long hand pointing towards the number 8 on a dial. Some watches, such as the Timex Datalink USB, feature dot matrix displays.

The first digital watch, a Pulsar prototype in 1970, was developed jointly by Hamilton Watch Company and Electro-Data. John Bergey, the head of Hamilton's Pulsar division, said that he was inspired to make a digital timepiece by the then-futuristic digital clock that Hamilton themselves made for the 1968 science fiction film 2001: A Space Odyssey. On April 4, 1972 the Pulsar was finally ready, made in 18-carat gold and sold for $2,100 at retail. It had a red light-emitting diode (LED) display. Another early digital watch innovator, Roger Riehl's Synchronar Mark 1, provided an LED display and used solar cells to power the internal nicad batteries.

Most watches with LED displays required that the user press a button to see the time displayed for a few seconds, because LEDs used so much power that they could not be kept operating continuously. Watches with LED displays were popular for the next few years, but soon the LED displays were superseded by liquid crystal displays (LCDs), which used less battery power and were much more convenient in use, with the display always visible and no need to push a button before seeing the time. The first LCD watch with a six-digit LCD was the 1973 Seiko 06LC, although various forms of early LCD watches with a four-digit display were marketed as early as 1972 including the 1972 Gruen Teletime LCD Watch, and the Cox Electronic Systems Quarza.

Digital watches were very expensive and out of reach to the common consumer up until 1975, when Texas Instruments started to mass produce LED watches inside a plastic case. These watches, which first retailed for only $20, and then $10 in 1976, saw Pulsar lose $6 million and the brand sold to competitors twice in only a year, eventually becoming a subsidiary of Seiko and going back to making only analogue quartz watches.

From the 1980s onward, technology in digital watches vastly improved. In 1982 Seiko produced a watch with a small TV screen built in and Casio produced a digital watch with a thermometer and another watch that could translate 1,500 Japanese words into English. In 1985, Casio produced the CFX-400 scientific calculator watch. In 1987 Casio produced a watch that could dial your telephone number and Citizen revealed one that would react to your voice. In 1995 Timex release a watch which allowed the wearer to download and store data from a computer to their wrist. Since their apex during the late 1980s to mid 1990s high technology fad, digital watches have mostly devolved into a simpler, less expensive basic time piece with little variety between models.

Despite these many advances, almost all watches with digital displays are used as timekeeping watches. Expensive watches for collectors rarely have digital displays since there is little demand for them. Less craftsmanship is required to make a digital watch face and most collectors find that analog dials (especially with complications) vary in quality more than digital dials due to the details and finishing of the parts that make up the dial (thus making the differences between a cheap and expensive watch more evident).

Functions

All watches provide the time of day, giving at least the hour and minute, and usually the second. Most also provide the current date, and often the day of the week as well. However, many watches also provide a great deal of information beyond the basics of time and date. Some watches include alarms.Other elaborated and more expensive watches, both pocket and wrist models, also incorporate striking mechanisms or Repeater functions, so that the wearer could learn the time by the sound emanating from the watch. This announcement or striking feature is an essential characteristic of true clocks and distinguishes such watches from ordinary timepieces. This feature is available on most digital watches.

A complicated watch has one or more functionalities beyond the basic function of displaying the time and the date; such a functionality is called a complication. Two popular complications are the chronograph complication, which is the ability of the watch movement to function as a stopwatch, and the moonphase complication, which is a display of the lunar phase. Other more expensive complications include, Tourbillion, Perpetual calendar, Minute repeater and Equation of time. A truly complicated watch has many of these complications at once (see Calibre 89 from Patek Philippe for instance). Among watch enthusiasts, complicated watches are especially collectible. Some watches include a second 12-hour display for UTC (as Pontos Grand Guichet GMT).

The similar-sounding terms chronograph and chronometer are often confused, although they mean altogether different things. A chronograph is a type of complication, as explained above. A chronometer watch is an all-mechanical watch or clock whose movement has been tested and certified to operate within a certain standard of accuracy by the COSC (Contrôle Officiel Suisse des Chronomètres). The concepts are different but not mutually exclusive; a watch can be a chronograph, a chronometer, both, or neither.

Types

Fashion

Wristwatches are often treated as jewelry or as collectible works of art rather than as timepieces. This has created several different markets for wristwatches, ranging from very inexpensive but accurate watches intended for no other purpose than telling the correct time, to extremely expensive watches that serve mainly as personal adornment or as examples of high achievement in miniaturization and precision mechanical engineering. Still another market is that of “geek watches”—watches that not only tell the time, but incorporate computers, satellite navigation, complications of various orders, and many other features that may be quite removed from the basic concept of timekeeping. A dual time watch is designed for travelers, allowing them to see what time it is at home when they are elsewhere.

Most companies that produce watches specialize in one of these markets. Companies such as Breitling, Patek Phillipe, Jaeger-LeCoultre, Omega and Rolex specialize in watches as jewelry or fine mechanical devices, while companies such as Casio specialize in watches as timepieces or multifunctional computers. In the 1980s, the Swiss Swatch company hired graphic designers to redesign a new annual collection of non-repairable watches.

Computerized multi-function watches

Many computerized wristwatches have been developed, but none have had long-term sales success, because they have awkward user interfaces due to the tiny screens and buttons, and a short battery life. As miniaturized electronics became cheaper, watches have been developed containing calculators, tonometers, video games, digital cameras, keydrives, GPS receivers and cellular phones. In the early 1980s Seiko marketed a watch with a television in it. Such watches have also had the reputation as ugly and thus mainly geek toys. Several companies have however attempted to develop a computer contained in a wristwatch (see also wearable computer). As of 2005, these include the Timex Datalink, Seiko Ruputer, the Matsucom onHand, and the Fossil, Inc. Wrist PDA.

For space travel

Zero gravity environment and other extreme conditions encountered by astronauts in space requires the use of specially tested watches. On April 12, 1961, Yuri Gagarin wore a Shturmanskie (a transliteration of Штурманские which actually means "navigators") wristwatch during his historic first flight into space. The Shturmanskie was manufactured at the First Moscow Watch Factory.

Since 1964, the watches of the First Moscow Factory have been marked by a trademark "ПОЛЕТ" and "POLJOT", which means "flight" in Russian and is a tribute to the number of many space trips its watches have accomplished. In the late 1970s, Poljot launched a new chrono movement, the 3133. With a 23 jewel movement and manual winding (43 hours), it was a modified Russian version of the Swiss Valjoux 7734 of the early 1970s. Poljot 3133 were taken into space by astronauts from Russia, France, Germany and Ukraine. On the arm of Valeriy Polyakov, a Poljot 3133 chronograph movement-based watch set a space record for the longest space flight in history.

In 1994, after endurance tests on the margins of physics, the Star City Training Center chose the Fortis Official Cosmonauts Chronographas part of their official cosmonauts equipment. The space mission ”EUROMIR 1” crew was the first to be presented with the FORTIS COSMONAUTS SET and became the world's first automatic chrongraph in open space outside the space station.

In 2005, exactly 10 years after the first official flight Fortis remains as the exclusive supplier of manned space missions authorized by the Russian Federal Space Agency. The FORTIS B-42 OFFICIAL COSMONAUT CHRONOGRAPH floating in space on board the ISS, International Space Station.

During the 1960s, a large range of watches were tested for durability and precision under extreme temperature changes and vibrations. The Omega Speedmaster was selected by U.S. space agencies. TAG Heuer became the first Swiss watch in space thanks to an Heuer Stopwatch, worn by John Glenn in 1962 when he piloted the Friendship 7 on the first manned U.S. orbital mission.

The Breitling Navitimer Cosmonaute was designed with a 24-hour analog dial to avoid confusion between AM and PM, which are meaningless in space. It was first worn in space by U.S. astronaut Scott Carpenter on May 24, 1962 in the Aurora 7 mercury capsule. Since 1994 Fortis is the exclusive supplier for manned space missions authorized by the Russian Federal Space Agency. China National Space Administration (CNSA) astronauts wear the Fiyta spacewatches. (For a list of NASA-certified watches, see this footnote).

The watches are tested in still water, thus a watch with a 50 meter rating will be water resistant if it is stationary and under 50 meters of still water. For normal use, the ratings must then be translated from the pressure the watch can withstand to take into account the extra pressure generated by motion. Watches are classified by their degree of water resistance, which roughly translates to the following:

• Water resistant - Will tolerate splashes of water or rain
• 50 meter - Usable while showering, bathing, dishwashing, and swimming in shallow water
• 100 meter - Usable while swimming, and snorkeling
• 150 meter - Usable during general water sports
• 200 meter - Usable during general water sports, including free diving
• Diver's 150 meter - ISO standard for scuba diving

Some watches use bar instead of meters, which may then be multiplied by 10 to be approximately equal to the rating based on meters. Therefore, a 10 bar watch is equivalent to a 100 meter watch. Some watches are rated in atmospheres (atm), which are roughly equivalent to bar.

History

see History of watches In the 15th century, the increase in European sea-going navigation and mapping increased the demand for a portable timepiece, because the only way a ship could measure its longitude was by comparing the midday (high noon) time of the local longitude to that of a European meridian (usually Paris or Greenwich) using the time kept on a shipboard clock. However, the process was notoriously unreliable until the introduction of John Harrison's marine chronometer. For that reason, most maps from the 15th century through the 19th century have precise latitudes but distorted longitudes.

The first reasonably accurate mechanical clocks measured time with simple weighted pendulums, which are unworkable when irregular movement of the fulcrum occur whether at sea or in watches. The invention of a spring mechanism was crucial for portable clocks. In Tudor England, the development of "pocket-clockes" was enabled by the development of reliable springs and escapement mechanisms, which allowed clockmakers to compress a timekeeping device into a small, portable compartment.

In 1524, Peter Henlein created the first pocket watch. Early watches only had an hour hand—a minute hand would have been useless because of the inaccuracy of the watch mechanism. Eventually, miniaturization of these spring-based designs allowed for accurate portable timepieces (marine chronometers) which worked well even at sea. In 1850, Aaron Lufkin Dennison founded Waltham Watch Company, which was the pioneer of the industrial manufacturing of pocket watches with interchangeable parts, the American System of Watch Manufacturing. Breguet developed the first self-winding watch known as the perpetual in 1780.

See also

• American Watchmakers-Clockmakers Institute
• Clock
• Mechanical watch
• Chronometer watch
• Marine chronometer
• Calculator watch
• Horology
• List of watch manufacturers
• National Association of Watch and Clock Collectors
• Timepiece
• Wearable computer
• Replica watch
• Compass direction using a watch
• BaselWorld
• Wrist watch (history)
• Georges Frederic Roskopf
• Jewel bearing
• Automatic Watch Winder

References

External links

• Portal of horology
• Federation of the Swiss Watch Industry FH
• FHH Fine watchmaking foundation
• AWCI American Watchmakers-Clockmakers Institute (United States)
• NAWCC The National Association of Watch and Clock Collectors (United States)
• Wrist Fashion - International Wristwatch News and Views
• Chronocentric.com
• UK patent GB218487, Improvements relating to wrist watches, 1923 patent resulting from John Harwood's invention of a practical self-winding watch mechanism.

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