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Early wrist watch by Waltham, worn by soldiers in World War I (Deutsches Uhrenmuseum, Inv. 47-3352)

A watch is a small clock, typically worn either on the wrist or attached on a chain and carried in a pocket; wristwatches, however, are the most common type of watch used today. Watches evolved in the 17th century from spring powered clocks, which appeared in the 15th century. The first watches were strictly mechanical. As technology progressed, the mechanisms used to measure time have, in some cases, been replaced by use of quartz vibrations or electromagnetic pulses.^[1] The first digital electronic watch was developed in 1970.^[2]

Before wristwatches became popular in the 1920s, most watches were pocket watches, which often had covers and were carried in a pocket and attached to a watch chain or watch fob.^[3] In the early 1900s, the wristwatch, originally called a Wristlet, was reserved for women and considered more of a passing fad than a serious timepiece. Men, who carried pocket watches, were quoted as saying they would "sooner wear a skirt as wear a wristwatch".^[4] This changed in World War I, when soldiers on the battlefield found pocket watches to be impractical and attached their watches to their wrist by a cupped leather strap. It is also believed that Girard-Perregaux equipped the German Imperial Navy with wristwatches in a similar fashion as early as the 1880s, to be used while synchronizing naval attacks and firing artillery.^[4]

Most inexpensive and medium-priced watches used mainly for timekeeping are electronic watches with quartz movements.^[1] 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. In addition to the time, modern watches often display the day, date, month and year, and electronic watches may have many other functions. Watches that provide additional time-related features such as timers, chronographs and alarm functions are not uncommon. Some modern designs even go as far as using GPS^[5] technology or heart-rate monitoring^[6] capabilities.

The study of timekeeping is known as horology.

History[link]

The earliest dated watch known, from 1530

This section requires expansion.

Watches evolved from portable spring driven clocks, which first appeared in 15th century Europe. Watches weren't widely worn in pockets until the 17th century.

Movement[link]

Different kinds of movements move the hands differently as shown in this 2 second exposure. The left watch has a mechanical 1/6 s movement, the right one has a "1 s" quartz movement

A Russian mechanical watch 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 watch face indicating the time.

Mechanical movements[link]

Compared to electronic movements, mechanical watches are less accurate, often with errors of seconds per day, and they are sensitive to position, temperature^[7] and magnetism.^[8] They are also costly to produce, require regular maintenance and adjustment, and are more prone to failure. Nevertheless, the craftsmanship of mechanical watches still attracts interest from part of the watch-buying public. Skeleton watches are designed to leave the mechanism visible for aesthetic purposes.

Mechanical movements use an escapement mechanism to control and limit the unwinding and winding parts of a spring, converting what would otherwise be a simple unwinding into a controlled and periodic energy release. Mechanical movements also use a balance wheel together with the balance spring (also known as a hairspring) to control motion of the gear system of the watch in a manner analogous to the pendulum of a pendulum clock. The tourbillon, an optional part for mechanical movements, is a rotating frame for the escapement, which is used to cancel out or reduce the effects of gravitational bias to the timekeeping. Due to the complexity of designing a tourbillon, they are very expensive, and only found in "prestige" watches.

The pin-lever escapement (called the Roskopf movement after its inventor, Georges Frederic Roskopf), which is a cheaper version of the fully levered movement, was manufactured in huge quantities by many Swiss manufacturers as well as Timex, until it was replaced by quartz movements.^[9][10][11]

Tuning-fork watches use a type of electromechanical movement. Introduced by Bulova in 1960, they use a tuning fork with a precise frequency (most often 360 hertz) to drive a mechanical watch. The task of converting electronically pulsed fork vibration into rotary movement is done via two tiny jeweled fingers, called pawls. Tuning-fork watches were rendered obsolete when electronic quartz watches were developed. Quartz watches were cheaper to produce and even more accurate.

Traditional mechanical watch movements use a spiral spring called a mainspring as a power source. In manual watches the spring must be rewound periodically by the user by turning the watch crown. Antique pocketwatches were wound by inserting a separate key into a hole in the back of the watch and turning it. Most modern watches are designed to run 40 hours on a winding and thus must be wound daily, but some run for several days and a few have 192-hour mainsprings and are wound weekly.

Automatic watches[link]

Automatic watch: An eccentric weight, called a rotor, swings with the movement of the wearer's body and winds the spring

A self-winding or automatic watch is one that rewinds the mainspring of a mechanical movement by the natural motions of the wearer's body. The first self-winding mechanism was invented for pocket watches in 1770 by Abraham-Louis Perrelet,^[12] 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 constant winding without special action from the wearer; it works by an eccentric weight, called a winding rotor, which 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 are inadequate to keep the watch wound.

Electronic movements[link]

Electronic movements have few or no moving parts, as they use the piezoelectric effect in a tiny quartz crystal to provide a stable time base for a mostly electronic movement. The crystal forms a quartz oscillator which resonates at a specific and highly stable frequency, and which can be used to accurately pace a timekeeping mechanism. For this reason, electronic watches are often called quartz watches. Most quartz movements are primarily electronic but are geared to drive mechanical hands on the face of the watch in order to provide a traditional analog display of the time, which is still preferred by some consumers.

Prototype of a Quartz Wristwatch, CEH Switzerland, 1967

In 1959 Seiko gave an order to Epson (a daughter company of Seiko and the actual brain behind the quartz revolution) to start developing a quartz wristwatch. The project was codenamed 59A and by the 1964 Tokyo Summer Olympics, Seiko had a working prototype of a portable quartz watch which took part in time measurements throughout the event.

The first prototypes of an electronic quartz wristwatch (not just portable quartz watches as the Seiko timekeeping devices at the Tokyo Olympics in 1964) were made by the CEH research laboratory in Neuchâtel, Switzerland. From 1965 through 1967 pioneering development work was done on a miniaturized 8192 Hz quartz oscillator, a thermo-compensation module and an inhouse-made, dedicated integrated circuit (unlike the hybrid circuits used in the later Seiko Astron wristwatch). As a result, the BETA 1 prototype set new timekeeping performance records at the International Chronometric Competition held at the Observatory of Neuchâtel in 1967.^[13]

Quartz Movement of the Seiko Astron, 1969 (Deutsches Uhrenmuseum, Inv. 2010-006)

The first quartz watch to enter production was the Seiko 35 SQ Astron, which hit the shelves on December 25, 1969. One particularly interesting decision made by Seiko at that time was to not patent the whole movement of the quartz wristwatch, thus allowing other manufacturers to benefit from the Seiko technology. This played a major role in the popularity and quick development of the quartz watch, which in less than a decade was dominant in the watch market, nearly ending an almost 100 years of mechanical wristwatch heritage. The modern quartz movements are produced in very large quantities, and even the cheapest wristwatches typically have quartz movements. Whereas mechanical movements can typically be off by several seconds a day, an inexpensive quartz movement in a child's wristwatch may still be accurate to within half a second per day—ten times better than a mechanical movement.^[14]

After a consolidation of the mechanical watch industry in Switzerland during the 1970s, mass production of quartz wristwatches took off under the leadership of the Swatch Group of companies, a Swiss conglomerate with vertical control of the production of Swiss watches and related products. For quartz wristwatches, subsidiaries of Swatch manufactured watch batteries (Renata), oscillators (Oscilloquartz) and integrated circuits (Ebauches Electronic SA). The launch of the new SWATCH brand in 1983, was marked by bold new styling, design and marketing. Today, the Swatch Group is the world's largest watch company.

Seiko's efforts to combine the quartz and mechanical movements bore fruit after 20 years of research, leading to the introduction of the Seiko Spring Drive, first in a limited domestic market production in 1999 and to the world in September 2005. The Spring Drive manages to keep time within quartz standards without the use of a battery, using a traditional mechanical gear train powered by a spring, while at the same time doesn't have the need of a balance wheel either.

Radio time signal watches are a type of electronic quartz watch which synchronizes (time transfer) its time with an external time source such as in atomic clocks, time signals from GPS navigation satellites, the German DCF77 signal in Europe, WWVB in the US, and others. Movements of this type may -among others- synchronize not only the time of day but also the date, the leap-year status of the current year, and the current state of daylight saving time (on or off). However, other than the radio receiver these watches are normal quartz watches in all other aspects.

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 a 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, as a battery is composed of multiple 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 cells but providing shorter life. Rechargeable batteries are used in some solar powered watches.

Some electronic watches are also powered by the movement of the wearer of the watch. For instance, Seiko's Kinetic powered quartz watches make use of the motion of the wearer's arm turning a rotating weight which causes a tiny 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.

Solar powered 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.^[15]

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[link]

Analog[link]

Poljot chronograph

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 usually have a second hand that snaps every second to the next marker. Watches powered by a mechanical movement appears to have a gliding second hand, although it is actually not gliding; the hand merely moves in smaller steps, typically 1/5 of a second, corresponding to the beat (half period) of the balance wheel. In some escapements (for example the duplex escapement), the hand advances every two beats (full period) of the balance wheel, typically 1/2 second in those watches, or even every four beats (two periods, 1 second), in the double duplex escapement. A truly gliding second hand is achieved with the tri-synchro regulator of Spring Drive watches. 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 wrist. This is the case if one is right-handed and the watch is worn on the left wrist (as is traditionally done). If one is left-handed and wears the watch on the right wrist, one has to remove the watch from the wrist to reset the time or to wind the watch.

Analog watches as well as clocks are often marketed showing a display time of approximately 10:09 or 10:10. This creates a visually pleasing smile-like face on upper half of the watch, in addition to enclosing the manufacturer's name. Digital displays often show a time of 12:08, 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.^[16][17]

Analog watch displays can be used to indicate cardinal direction due to the relation between the position of the hour hand and the position of the Sun in the sky. By rotating the watch so that the hour hand points toward the Sun, the point halfway between the hour hand and 12 o'clock will indicate south when observing from a position in the Northern hemisphere. In the Southern hemisphere, the point halfway between the hour hand pointed at the sun and 12 o'clock on the dial indicates North.

Digital[link]

Cortébert digital mechanical pocket watch. 1890s

Cortébert digital mechanical wristwatch. 1920s

A silver Pulsar LED watch from 1976.

A digital display simply shows the time as a number, e.g., 12:08 instead of a short hand pointing towards the number 12 and a long hand 8/60 of the way round the dial. The digits are usually shown as a seven-segment display.

The first digital mechanical pocket watches appeared in late 19th century. In the 1920s the first digital mechanical wristwatches appeared.

The first digital electronic watch, a Pulsar LED 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. It had a red light-emitting diode (LED) display.

Digital LED watches were very expensive and out of reach to the common consumer until 1975, when Texas Instruments started to mass produce LED watches inside a plastic case. These watches, which first retailed for only $20,^[18] reduced to $10 in 1976, saw Pulsar lose $6 million and the Pulsar brand sold to Seiko.^[19]

An early LED watch that was rather problematic was The Black Watch made and sold by British company Sinclair Research in 1975. This was only sold for a few years, as production problems and returned (faulty) product forced the company to cease production.

A digital watch displaying the time, seconds, and date

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. Usually the LED display color would be red. Watches with LED displays were popular for a 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. Only in darkness you had to press a button to lit the display with a tiny light bulb, later illuminating LEDs. 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.^[20] In Switzerland, Ebauches Electronic SA presented a prototype eight-digit LCD wristwatch showing time and date at the MUBA Fair, Basle, in March 1973, using a Twisted Nematic LCD manufactured by Brown, Boveri & Cie, Switzerland, which became the supplier of LCDs to Casio for the CASIOTRON watch in 1974.^[21]

From the 1980s onward, digital watch technology vastly improved. In 1982 Seiko produced a watch with a small television screen built in,^[22] and Casio produced a digital watch with a thermometer as well as another 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 released a watch which allowed the wearer to download and store data from a computer to their wrist. Some watches, such as the Timex Datalink USB, feature dot matrix displays. Since their apex during the late 1980s to mid 1990s high technology fad, digital watches have mostly become simpler, less expensive time pieces 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[link]

The Rolex Submariner, an officially certified chronometer

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 elaborate 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 functions 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 Tourbillon, 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). Some watches can both indicate the direction of Mecca^[23] and have alarms that can be set for all daily prayer requirements.^[24] 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 has a stopwatch complication, as explained above, while a chronometer watch has a high quality mechanical or a thermo-compensated movement that 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; so a watch can be a chronograph, a chronometer, both, or neither.

Timex Datalink USB Dress edition from 2003 with a dot matrix display; the Invasion video game is on the screen

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, barometers, altimeters, a compass using both hands to show the N/S direction, 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 unsightly and thus mainly geek toys. Several companies have however attempted to develop a computer contained in a wristwatch (see also wearable computer).

Braille watches have analog displays with raised bumps around the face to allow blind users to tell the time. Their digital equivalents use synthesised speech to speak the time on command.

Uses[link]

Fashion[link]

Wristwatches are often appreciated as jewelry or as collectible works of art rather than just 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 (featuring jewel bearings to hold gemstones) or as examples of high achievement in miniaturization and precision mechanical engineering.

Traditionally, men's dress watches appropriate for informal (business), semi-formal, and formal attire are gold, thin, simple, and plain, but increasingly rugged, complicated, or sports watches are considered acceptable for such attire. Some dress watches have a cabochon on the crown and many women's dress watches have faceted gemstones on the face, bezel, or bracelet. Some are made entirely of facetted sapphire (corundum).^[25]

Many fashion and department stores offer a variety of less-expensive, trendy, "costume" watches (usually for women), many of which are similar in quality to basic quartz timepieces but which feature bolder designs. In the 1980s, the Swiss Swatch company hired graphic designers to redesign a new annual collection of non-repairable watches.

Most companies that produce watches specialize in one or some of these markets. Companies such as Patek Philippe, Blancpain and Jaeger-LeCoultre specialize in simple and complicated mechanical dress watches; companies such as Omega SA, Ball Watch Company, TAG Heuer, Sinn, Breitling, Panerai and Rolex specialize in rugged, reliable mechanical watches for sport and aviation use. Companies such as Casio, Timex, and Seiko specialize in watches as affordable timepieces or multifunctional computers.

Trade in counterfeit watches, which mimic expensive brand-name watches, constitutes an estimated US$1 billion market per year.^[26]

Space[link]

The Omega Speedmaster, selected by U.S. space agencies

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 "navigator's") wristwatch during his historic first flight into space. The Shturmanskie was manufactured at the First Moscow Factory. Since 1964, the watches of the First Moscow Factory have been marked by the trademark "ПОЛЕТ", transliterated as "POLJOT", which means "flight" in Russian and is a tribute to the 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.^[27]

Astronaut Nancy J. Currie wears the Timex Ironman Triathlon Datalink model 78401 during STS 88.

Through the 1960s, a large range of watches were tested for durability and precision under extreme temperature changes and vibrations. The Omega Speedmaster Professional was selected by NASA, the U.S. space agency. Heuer became the first Swiss watch in space thanks to a 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.^[28] 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^[29] spacewatches. At BaselWorld, 2008, Seiko announced the creation of the first watch ever designed specifically for a space walk, Spring Drive Spacewalk. Timex Datalink is flight certified by NASA for space missions and is one of the watches qualified by NASA for space travel. Both the Casio G-Shock DW-5600C and 5600E are Flight-Qualified for NASA space travel.^{[30][31][32][33]} The various Datalink models were used both by cosmonauts and astronauts.

Scuba diving[link]

Seiko 7002-7020 Diver's 200 m on a 4-ring NATO style strap

Watches may be crafted to become water resistant. These watches are sometimes called diving watches when they are suitable for scuba diving or saturation diving. The International Organization for Standardization issued a standard for water resistant watches which also prohibits the term "waterproof" to be used with watches, which many countries have adopted.

Water resistance is achieved by the gaskets which forms a watertight seal, used in conjunction with a sealant applied on the case to help keep water out. The material of the case must also be tested in order to pass as water resistant.^[34]

None of the tests defined by ISO 2281 for the Water Resistant mark are suitable to qualify a watch for scuba diving. Such watches are designed for everyday life and must be water resistant during exercises such as swimming. They can be worn in different temperature and pressure conditions but are under no circumstances designed for scuba diving.

The standards for diving watches are regulated by the ISO 6425 international standard. The watches are tested in static or still water under 125% of the rated (water)pressure, thus a watch with a 200 metre rating will be water resistant if it is stationary and under 250 metres of static water. The testing of the water resistance is fundamentally different from non-dive watches, because every watch has to be fully tested. Besides water resistance standards to a minimum of 100 metre depth rating ISO 6425 also provides eight minimum requirements for mechanical diver's watches for scuba diving (quartz and digital watches have slightly differing readability requirements). For diver's watches for mixed-gas saturation diving two additional requirements have to be met.

Watches are classified by their degree of water resistance, which roughly translates to the following (1 metre = 3.281 feet):^[35]

Some watches use bar instead of meters, which may then be multiplied by 10, and then subtracted by 10. This is because 1 bar is equal to one atmosphere or 10 metres of water (therefore 1 bar at the surface and one more each 10 metres). to be approximately equal to the rating based on metres. Therefore, a 5 bar watch is equivalent to a 40 metre watch. Some watches are rated in atmospheres (atm), which are roughly equivalent to bar.

See also[link]

• American Watchmakers-Clockmakers Institute
• List of watch manufacturers
• Marine chronometer
• National Association of Watch and Clock Collectors
• Tachymeter
• WatchTime Magazine
• Wristwatch computer

References[link]

Further reading[link]

• De Carle, Donald, (Illustrations by E. A. Ayres), Practical Watch Repairing, 3rd edition, New York : Skyhorse Pub., 2008. ISBN 978-1-60239-357-8. Significant information on watches, their history, and inner workings.
• Denn, Mark, "The Tourbillon and How It Works", IEEE Control Systems Magazine, June 2010, IEEE Control Systems Society, DOI 10.1109/MCS.2010.936291.

External links[link]

Look up watch in Wiktionary, the free dictionary.

Wikimedia Commons has media related to: Watch

• Philadelphia Exhibition 1876 Report to the Federal High Council by Ed. Favre-Perret (1877)
• American and Swiss Watchmaking in 1876 by Jacques David
• The Watch Factories of America Past and Present by Henry G. Abbott (1888)
• Watchmaking and the American System of Manufacturing (2009)
• Federation of the Swiss Watch Industry FH
• UK patent GB218487, Improvements relating to wrist watches, 1923 patent resulting from John Harwood's invention of a practical self-winding watch mechanism.
• The Most Expensive Watches

David Tennant
David Tennant at Comic-Con 2009
Born	David John McDonald (1971-04-18) 18 April 1971 (age 41) Bathgate, West Lothian, Scotland
Occupation	Actor
Years active	1987–present
Spouse	Georgia Moffett (2011–present)
Children	1 daughter, 1 son (adopted)
Parents	Alexander McDonald Helen McDonald (deceased)[1]

David Tennant (born David John McDonald; 18 April 1971) is a Scottish actor. In addition to his work in theatre, including a widely praised Hamlet,^[2][3] Tennant is best known for his role as the tenth incarnation of the Doctor in Doctor Who, along with the title role in the TV serial Casanova (2005) and as Barty Crouch, Jr., in the film Harry Potter and the Goblet of Fire (2005).

Early life[link]

Tennant was born in Bathgate, West Lothian, Scotland, the son of Essdale Helen (née McLeod) and The Rev. Alexander McDonald (known to family and friends as Sandy McDonald).^[4] He grew up with his brother Blair and sister Karen^[5] in Ralston, Renfrewshire, where his father was the local Church of Scotland minister.^[6][7][8] Tennant's maternal great-grandparents, William and Agnes Blair, were staunch Protestants from Derry in Ulster, the northern province of Ireland, and were among the signatories of the Ulster Covenant in 1912; William was a member of the Grand Orange Lodge of Ireland. Tennant's maternal grandfather, footballer Archie McLeod, met William and Agnes's daughter Nellie while playing for Derry City.^[9]

At the age of three, Tennant told his parents that he wanted to become an actor because he was a fan of Doctor Who,^[10] but they tried to encourage him to aim for more conventional work.^[5] He watched almost every Doctor Who episode for years, and he spoke to Tom Baker at a book-signing event in Glasgow.^[5] Tennant says he was "absurdly single-minded" in pursuing an acting career. Tennant was educated at Ralston Primary and Paisley Grammar School, where he enjoyed a fruitful relationship with English language teacher Moira Robertson, who was among the first to recognise his potential.^[11] He acted in school productions throughout primary and secondary school.

Tennant's talent at this young age was spotted by actress Edith MacArthur; after seeing his first role at age 11, she told his parents he would become a successful stage actor.^[12] Tennant also attended Saturday classes at the Royal Scottish Academy of Music and Drama; at 16, he passed an audition for the Academy, one of their youngest students, and studied there between the ages of 17–20, taking his stage name from the Pet Shop Boys frontman Neil Tennant^[13] after reading a copy of Smash Hits magazine^[14] because there was another David McDonald already on the books of the Equity union. Tennant was flatmates with friend Louise Delamere while at the Academy and gained a bachelor's degree.

Career[link]

Early work[link]

Tennant made his professional acting debut while still in secondary school. When he was 16 he acted in an anti-smoking film made by the Glasgow Health Board which aired on television and was also screened in schools.^[12] The following year, he played a role in an episode of Dramarama. Tennant's first professional role upon graduating from drama school was in a staging of The Resistible Rise of Arturo Ui costarring Ashley Jensen, one of a few plays in which he performed as part of the agitprop 7:84 Theatre Company. Tennant also made an early television appearance in the Scottish TV sitcom Rab C Nesbitt as a transsexual barmaid called Davina. In the 1990s, Tennant appeared in several plays at the Dundee Repertory Theatre.^[15]

Tennant's first major TV role was as the manic depressive Campbell in the Scottish drama series Takin' Over the Asylum (1994). During filming, Tennant met comic actress and writer Arabella Weir. When he moved to London shortly afterwards he lodged with Weir for five years and became godfather to her youngest child. He has subsequently appeared alongside Weir in many productions; as a guest in her spoof television series, Posh Nosh; in the Doctor Who audio drama Exile—during which Weir played an alternate version of the Doctor—and as panellists on the West Wing Ultimate Quiz on More4 (Weir later guest-starred on Doctor Who itself after Tennant left the series). One of his earliest big screen roles was in Jude (1996), in which he shared a scene with Christopher Eccleston, playing a drunken undergraduate who challenges Eccleston's Jude to prove his intellect. Coincidentally, Eccleston later portrayed the incarnation of The Doctor immediately preceding Tennant's.

Tennant developed his career in the British theatre, frequently performing with the Royal Shakespeare Company. His first Shakespearean role for the RSC was in As You Like It (1996); having auditioned for the role of Orlando, the romantic lead, he was instead cast as the jester Touchstone, which he played in his natural Scottish accent.^[16] He subsequently specialised in comic roles, playing Antipholus of Syracuse in The Comedy of Errors and Captain Jack Absolute in The Rivals, although he also played the tragic role of Romeo in Romeo and Juliet.

Tennant also contributed to several audio dramatisations of Shakespeare for the Arkangel Shakespeare series (1998). His roles include a reprisal of his Antipholus of Syracuse in The Comedy of Errors, as well as Launcelot Gobbo in The Merchant of Venice, Edgar/Poor Tom in King Lear, and Mercutio in Romeo and Juliet, all of which he performs in his natural accent. In 1995, Tennant appeared at the Royal National Theatre, London, playing the role of Nicholas Beckett in Joe Orton's What the Butler Saw. The plot required Tennant to appear naked on stage. In television, Tennant appeared in the first episode of Reeves and Mortimer's revamped Randall & Hopkirk (Deceased) in 2000, playing an eccentric artist. This is one of his few TV roles in his native Scottish accent.

During the Christmas season of 2002, he starred in a series of television advertisements for Boots the Chemists.^[17] Tennant began to appear on television more prominently in 2004 and 2005, when he appeared in a dramatisation of He Knew He Was Right (2004), Blackpool (2004), Casanova (2005) and The Quatermass Experiment (2005). In film, he appeared in Stephen Fry's Bright Young Things (2003) and played Barty Crouch Jr. in Harry Potter and the Goblet of Fire (2005).

[edit] Doctor Who (2005–2010)

Tennant with Doctor Who showrunner Russell T Davies (left), regular director Euros Lyn (centre right), and executive producer Julie Gardner (right) at Comic-Con in July 2009

Doctor Who returned to British screens in 2005, with Christopher Eccleston playing the role of the Ninth Doctor. After Eccleston's announcement on 31 March 2005 that he would not be returning for a second series, the BBC confirmed Tennant as his replacement in a press release on 16 April 2005. He made his first, brief appearance as the Tenth Doctor in the episode "The Parting of the Ways" (2005) at the end of the regeneration scene, and also appeared in a special 7-minute mini-episode shown as part of the 2005 Children in Need appeal, broadcast on 18 November 2005. He began filming the new series of Doctor Who in late July 2005. His first full-length outing as the Doctor was a 60-minute special, "The Christmas Invasion", first broadcast on Christmas Day 2005.

Tennant has expressed enthusiasm about fulfilling his childhood dream. He remarked to an interviewer for GWR FM, "Who wouldn't want to be the Doctor? I've even got my own TARDIS!" In 2006, readers of Doctor Who Magazine voted Tennant 'Best Doctor!', over perennial favourite Tom Baker.^[18] In 2007, Tennant's Doctor was voted the "coolest character" on UK television in a Radio Times survey.^[19] When Tennant was cast as Eccleston's successor, he had wanted to use his native Scottish accent and become 'the first kilted Doctor' according to an interview in the Daily Star, but writer Russell T Davies did not want the Doctor's accent 'touring the regions', so he used "estuary" English instead.

Tennant had previously had a small role in the BBC's animated Doctor Who webcast Scream of the Shalka. Not originally cast in the production, Tennant happened to be recording a radio play in a neighbouring studio, and when he discovered what was being recorded next door managed to convince the director to give him a small role. This personal enthusiasm for the series had also been expressed by his participation in several audio plays based on the Doctor Who television series which had been produced by Big Finish Productions, although he did not play the Doctor in any of these productions. His first such role was in the Seventh Doctor audio Colditz, where he played a Nazi lieutenant guard at Colditz Castle. In 2004 Tennant played a lead role in the Big Finish audio play series Dalek Empire III. He played the part of Galanar, a young man who is given an assignment to discover the secrets of the Daleks. In 2005, he starred in UNIT: The Wasting for Big Finish, recreating his role of Brimmicombe-Wood from a Doctor Who Unbound play, Sympathy for the Devil. In both of these audio productions Tennant worked alongside Doctor Who alumnus Nicholas Courtney, who reprised the character of Sir Alastair Gordon Lethbridge-Stewart. He also played an unnamed Time Lord in another Doctor Who Unbound play Exile. UNIT: The Wasting, was recorded between Tennant getting the role of the Doctor and it being announced. He also played the title role in Big Finish's adaptation of Bryan Talbot's The Adventures of Luther Arkwright (2005). In 2006, he recorded abridged audio books of The Stone Rose by Jacqueline Rayner, The Feast of the Drowned by Stephen Cole and The Resurrection Casket by Justin Richards, for BBC Worldwide.

He made his directorial debut on the Doctor Who Confidential episode that accompanies Steven Moffat's episode "Blink", entitled "Do You Remember The First Time?", which aired on 9 June 2007. In 2007, Tennant's Tenth Doctor appeared with Peter Davison's Fifth Doctor in a Doctor Who special for Children in Need, written by Steven Moffat and entitled "Time Crash". This was the first "multi-Doctor" story in the series since The Two Doctors in 1985 (not counting the 1993 special Dimensions in Time).^[20] Tennant also later performed alongside Davison's daughter, Georgia Moffett, in the 2008 episode "The Doctor's Daughter" with her taking the titular role as Jenny.

Tennant also featured as the Doctor in an animated version of Doctor Who for Totally Doctor Who, The Infinite Quest, which aired on CBBC. He also starred as the Doctor in another animated six-part Doctor Who series, Dreamland.^[21] Tennant guest starred as the Doctor in a two-part story in Doctor Who spin-off The Sarah Jane Adventures, broadcast in October 2009.^[22] Tennant continued to play the Tenth Doctor into the revived programme's fourth series in 2008. However, on 29 October 2008, Tennant announced that he would be stepping down from the role after three full series.^[23] He played the Doctor in four special episodes in 2009, before his final episode aired on 1 January 2010. The Daily Mirror reported that Tennant was forbidden from attending Doctor Who fan conventions while playing the role. This was done to avoid the chance that Tennant could accidentally let slip any plot points during filming of the series.^[24] He said at the Children in Need concert that his favourite Doctor Who story is Genesis of the Daleks from the Tom Baker era, while another interview included him mentioning that his favourite classic monsters were the Zygons; although he never appeared in a television story with the Zygons, his Doctor confronted them in the novel Sting of the Zygons.

Other television roles (2005–present)[link]

While playing the Doctor, Tennant was also in the early December 2005 ITV drama Secret Smile. His performance as Jimmy Porter in Look Back in Anger at the Theatre Royal, Bath and Lyceum Theatre, Edinburgh was recorded by the National Video Archive of Performance for the Victoria and Albert Museum Theatre Collection. He revived this performance for the anniversary of the Royal Court Theatre in a rehearsed reading. In January 2006, he took a one-day break from shooting Doctor Who to play Richard Hoggart in a dramatisation of the 1960 Lady Chatterley's Lover obscenity trial, The Chatterley Affair. The play was written by Andrew Davies and directed by Doctor Who's James Hawes for the digital television channel BBC Four. Hoggart's son Simon Hoggart praised Tennant's performance in The Guardian newspaper.^[25]

On 25 February 2007, Tennant starred in Recovery, a 90-minute BBC1 drama written by Tony Marchant. Tennant played Alan, a self-made building site manager who attempted to rebuild his life after suffering a debilitating brain injury. His costar in the drama was friend Sarah Parish, with whom he had previously appeared in Blackpool and an episode of Doctor Who. She joked that "we're like George and Mildred – in 20 years' time we'll probably be doing a ropey old sitcom in a terraced house in Preston."^[26] Later in 2007 he starred in Learners, a BBC comedy drama written by and starring Jessica Hynes (another Doctor Who costar, in the episodes "Human Nature", "The Family of Blood" and "The End of Time"), in which he played a Christian driving instructor who became the object of a student's affection. Learners was broadcast on BBC One on 11 November 2007. Tennant had a cameo appearance as the Doctor in the 2007 finale episode of the BBC/HBO comedy series Extras alongside Ricky Gervais. In November 2008 Tennant played Sir Arthur Eddington in the BBC and HBO biopic Einstein and Eddington, which was filmed in Cambridge and Hungary.^[27]

In 2009 he worked on a film version of the RSC's 2008 Hamlet for BBC2. From October 2009, he hosted the Masterpiece Contemporary programming strand on the American Public Broadcasting Service.^[28] In December 2009, he filmed the lead in an NBC pilot, Rex Is Not Your Lawyer, playing Rex, a Chicago lawyer who starts to coach clients to represent themselves when he starts suffering panic attacks.^[29] The pilot was not picked up and the project was shelved.^[30][31] In October 2010 he starred as Dave, a man struggling to raise five children after the death of his partner, in the British drama Single Father. For this role he was nominated as Best Actor at the Royal Television Society Programme Awards 2010.

In 2011 he starred in the BBC Two British TV film United, which tells the story of the Manchester United "Busby Babes" team and the 1958 Munich air disaster, playing coach and assistant manager Jimmy Murphy.^[32] In September 2011, he appeared in a guest role in one episode of the comedy series This is Jinsy, and also started filming True Love, a semi-improvised BBC1 drama series, on location in Margate, Kent. The series is due to air in June 2012. In April 2012, Tennant will play the lead in a one-off drama The Minor Character for Sky Arts.^[33] In April 2012 it was announced that he will star as Jean-François Mercier in BBC4 drama series Spies of Warsaw, which films in Poland between April and June.^[34]

Other work (2007–present)[link]

Tennant was the "Star in a Reasonably Priced Car" on Top Gear in December 2007, where he claimed to have unsuccessfully auditioned for a role on Taggart 26 times.^[35] Tennant is the voice behind the 2007 advertising campaign for catalogue retailer Argos, and appeared in adverts for The Proclaimers' 2008 album and learndirect in June 2008 (using his natural Scottish accent in both). Tennant also lent his voice to adverts for Tesco Mobile, Nintendo Wii, and American Express.

Tennant appeared in Derren Brown's Trick or Treat.^[36] In the 26 April–2 May issue of TV & Satellite Week, Brown is quoted as saying: "One of the appeals of Doctor Who for David is time travel, so I wanted to give him that experience. He was open and up for it, and I got a good reaction. He's a real screamer!" The episode aired on Channel 4 on 16 May 2008, and showed Tennant apparently predicting future events correctly by using automatic writing. Tennant also returned for the final episode of the series with the rest of the participants from the other episodes in the series to take part in one final experiment.

Tennant at Stratford-upon-Avon

Tennant appeared in the 2008 episode "Holofile 703: Us and Phlegm" of the radio series Nebulous (a parody of Doctor Who) in the role of Doctor Beep, using his Lothian accent. Also in 2008, Tennant voiced the character of Hamish the Hunter in the 2008 English language DVD rerelease of the 2006 animated Norwegian film, Free Jimmy, alongside Woody Harrelson. The English language version of the film has dialogue written by Simon Pegg, who also starred in it as a main voice actor. In early 2009, Tennant narrated the digital planetarium space dome film "We are Astronomers"^[37] commissioned by the UK's National Space Centre. On 13 March 2009, he presented Red Nose Day 2009 with Davina McCall. He joined Franz Ferdinand onstage to play the guitar on their song "No You Girls" on a special Comic Relief edition of Top of the Pops. In summer 2009, Tennant filmed St. Trinian's II: The Legend of Fritton's Gold. The film was released in December 2009.

At the October 2009 Spooky Empire convention, John Landis announced Tennant's casting in his movie Burke and Hare, starring alongside Simon Pegg.^[38] In January 2010 it was announced Tennant had dropped out of the film (replaced by Andy Serkis) due to scheduling problems. In November 2009, Tennant cohosted the Absolute Radio Breakfast Show with Christian O'Connell for three consecutive days.^[39] He returned to cohost the show for one day in October 2010^[40] and again in September 2011. Tennant also provides the narration and all the character voices for the audio book versions of the Hiccup Horrendous Haddock III stories by Cressida Cowell such as How to Train Your Dragon. In these audio books, Tennant employs his vocal skills to create a vast cast of recognisably distinct voices. Some of his most memorable characterisations include the Norfolk yokel of Norbert the Nutjob, the broad Glaswegian of Gobber the Belch, the hissing and whining of Toothless the Dragon and the sly insinuations of Alvin the Treacherous. He also played the role of Spitelout in the recent animated film adaption of said books.

On 7 March 2010, he also appeared as George in a one-part BBC Radio 4 adaptation of Of Mice and Men in the Classic Serial strand.^[41] Tennant appeared alongside former costar Catherine Tate in the Shakespeare comedy Much Ado About Nothing at London's Wyndham's Theatre from 16 May 2011 to 3 September 2011.^[42] For his performance as Benedick he won the BroadwayWorld UK Award for Best Leading Actor in a Play.^[43] In September 2011, it was announced that Tennant will voice a character in the movie adaptation of Postman Pat named You Know You're the One with a planned 3D theatrical release for spring 2013.^[44]

In October 2011, Tennant started shooting the semi-improvised comedy film Nativity 2: The Second Coming in Coventry.^[45][46] Tennant plays two roles: the main character, put-upon teacher Mr Peterson, and his "golden boy" twin brother and rival.^[47] In April 2012, Tennant was the subject of a Virgin Media advert that was voluntarily withdrawn after a complaint lodged by BBC Worldwide. The advert, part of a multi-million pound campaign featuring Tennant, broke the corporation's guidelines by featuring references to Doctor Who that appeared to be a commercial endorsement of the service.^[48]

Royal Shakespeare Company (2008–2009)[link]

Despite his recent focus on television work, Tennant has described theatre work as his "default way of being".^[49] It was announced on 30 August 2007 that he would join the Royal Shakespeare Company (RSC), to play Hamlet (alongside Patrick Stewart) and Berowne (in Love's Labours Lost) during 2008.^[50] From August to November 2008 he appeared at the Courtyard Theatre in Stratford-upon-Avon as Hamlet, playing that role in repertory with Berowne that October and November.