Watch
From Phonology
- In naval parlance, watches are a timekeeping convention. The term in general use can mean any period of duty or responsibility, such as a hurricane watch.
A watch is a small portable clock that displays the time and sometimes the day, date, month and year. Today, watch is usually a contraction of wristwatch, a designation for the most popular type of watch, worn on the wrist.
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[edit] Overview
Today, the most common type of watch is the wristwatch, worn on the wrist and fastened with a watch strap, a bracelet made of real or synthetic leather, metal, nylon, or even ceramic. Before the the inexpensive miniaturization that became possible in the 20th century, most watches were pocket watches, which had covers and were carried separately, often in a pocket and attached to a watch chain.
Most inexpensive and medium-priced watches used mainly for timekeeping are electronic watches with quartz movements, powered by electricity. 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 many times less accurate than quartz movements. The most accurate watches have radio-controlled movements that are miniaturized, portable versions of radio clocks (q.v.).
[edit] Watch cases
[edit] Pocket clocks
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The earliest need for portability in time keeping was navigation and mapping in the 15th century. The latitude could be measured by looking at the stars, but 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)—a time kept on a shipboard clock. However, the process was notoriously unreliable until the introduction of John Harrison's 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 weighted pendulums, which are useless 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 through 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.<ref>Watch History</ref><ref>Concise history of watches</ref> It is rumoured that Henry VIII (the portrait of Henry VIII at this link shows the medallion thought to be the back of his watch) had a pocket clock which he kept on a chain around his neck. However, these watches only had an hour hand—a minute hand would have been useless considering the inaccuracy of the watch mechanism. Eventually, miniaturization of these spring-based designs allowed for accurate portable timepieces which worked well even at sea.
In 1850, Aaron Lufkin Dennison founded Waltham Watch Company, which was the pioneer of the industrial manufacturing of watches with interchangeable parts, the American System of Watch Manufacturing.
[edit] Wristwatches
The wristwatch was invented by Patek Philippe at the end of the 19th century. At the time, it was considered a woman's accessory. It was not until the beginning of the 20th century that the Brazilian inventor Alberto Santos-Dumont, who had difficulty checking the time while in his first aircraft (Dumont was working on the invention of the aeroplane), asked his friend Louis Cartier for a watch he could use more easily. Cartier gave him a leather-band wristwatch from which Dumont never separated. Being a popular figure in Paris, Cartier was soon able to sell these watches to other men. During the First World War, officers in all armies soon discovered that in battlefield situations, quickly glancing at a watch on their wrist was far more convenient than fumbling in their jacket pockets for an old-fashioned pocket watch. In addition, as increasing numbers of officers were killed in the early stages of the war, NCOs promoted to replace them often did not have pocket watches (traditionally a middle-class item out of the reach of ordinary working-class soldiers), and so relied on the army to provide them with timekeepers. As the scale of battles increased, artillery and infantry officers were required to synchronize watches in order to conduct attacks at precise moments, whilst artillery officers were in need of a large number of accurate timekeepers for rangefinding and gunnery. Army contractors began to issue reliable, cheap, mass-produced wristwatches which were ideal for these purposes. When the war ended, demobilized European and American officers were allowed to keep their wristwatches, helping to popularize the items amongst middle-class Western civilian culture.
Today, many Westerners wear watches on their wrists, a direct result of World War I. The trend has since spread to other parts of the world, wherever accurate and convenient time references are required.
[edit] Watch movements
A movement in watchmaking is the mechanism that measures the passage of time and displays the current time (and possibly the date) to the wearer of the watch. 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 mostly electronic movements, with mechanical hands on the face of the watch indicating the time.
[edit] Mechanical amovements
- See also Self-winding watch.
Purely mechanical watches are still popular, although they are most commonly seen among expensive, collectible watches. The best of these are among the most precisely engineered mechanisms in existence, and this accounts for much of the attraction of purely mechanical watches.
Mechanical watches keep very poor time, often with errors of seconds per day. They are frequently sensitive to position and temperature. They are costly to produce, they require regular maintenance and adjustment, and they are prone to failure (as compared with non-mechanical movements). For this reason, in inexpensive and moderately-priced timepieces that are intended only to provide their owners with the correct time, mechanical movements have been almost entirely replaced by electronic movements.
[edit] Tuning-fork movements
Tuning fork watches (first sold by Bulova) use a 360-Hertz tuning fork to drive a mechanical watch. The inventor, Max Hetzel was born in Basel, Switzerland, and joined the Bulova Watch Company of Bienne, Switzerland, in 1948. This outstanding engineer was the first one to use an electronic device—a transistor—in a wrist watch. Thus, Max Hetzel developed the first watch in the world that truly deserved the qualification “electronic” (even if it was only partially so): the world-famous Bulova Accutron.
Such watches were also sold by Swiss watch companies under license of Bulova (Universal, Eterna, Zenith, Allegro, IWC, ...) In 1974, after leaving Bulova, Hetzel developed a different tuning fork drive for Omega. This completely innovative watch design allowed Omega to bypass paying license fees for Bulova's tuning fork patents. The watch featured a cal. 1220 micromotor, and a tuning fork frequency of 720 Hertz.<ref>Omega Cal. 1220 (Megasonic)</ref> This development came too late, however, as the electronic quartz watch had become cheaper to produce and even more accurate.
[edit] Electronic movements
Electronic movements have few or no moving parts. Essentially all modern electronic movements use the piezoelectric effect in a tiny quartz crystal to provide a stable time base for a mostly electronic movement: the crystal resonates at a specific, highly stable frequency that can be used to accurate pace a timekeeping mechanism. For this reason, electronic watches are often called quartz watches. Most quartz movements are electronic for the most part, but ultimately 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 most consumers.
The first prototypes of electronic quartz watches were made by the CEH research laboratory in Switzerland in 1962. The first quartz watch to enter production was the Seiko 35 SQ Astron, which appeared in 1969. Modern quartz movements are produced in very large quantities, and even the cheapest wristwatches typically have quartz movements.
The best quartz movements are significantly more accurate than the worst, but the difference is much smaller than that found between mechanical movements and quartz movements. Quartz movements, even in their most inexpensive forms, are an order of magnitude more accurate than purely mechanical movements. Whereas mechanical movements are typically off by several seconds a day, an inexpensive quartz movement in a child's wristwatch may still be accurate to within 500 milliseconds per day—ten times better than a mechanical movement.
[edit] Radio-controlled movements
Some electronic quartz watches are able to synchronize themselves with an external time source. These sources include radio time signals directly driven by atomic clocks, time signals from GPS navigation satellites, and others. These watches are free-running most of the time, but periodically align themselves with the chosen external time source automatically, typically once a day.
Because these watches are regulated by an external time source of extraordinarily high accuracy, they are never off by more than a small fraction of a second a day (depending on the quality of their quartz movements), as long as they can receive the external time signals that they expect. Additionally, their long-term accuracy is comparable to that of the external time signals they receive, which in most cases (such as GPS signals and special radio transmissions of time based on atomic clocks) is better than one second in three million years. For all practical purposes, then, radio-controlled wristwatches keep perfect time.
Movements of this type 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). They obtain all of this information from the external signals that they receive. Because of this, they never require manual setting or resetting.
A disadvantage of radio-controlled movements is that they cannot synchronize if radio reception conditions are poor. Even in this case, however, they will simply run autonomously with the same accuracy as a normal quartz watch until they are next able to synchronize.
[edit] Power sources
[edit] Springs
Traditional, purely mechanical watch movements generally use a wound spring as a power source. The spring must be rewound by the user periodically (usually once a day, or once every few days).
[edit] Self-winding watches
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A self-winding mechanism is one that rewinds the mainspring (power spring) of a mechanical movement through some means other than explicit winding by the user.
The first self-winding mechanism, for fob-watches, was invented in 1770 by Abraham-Louis Perrelet<ref>Timekeeping in Europe and China : Watches & Wonders timeline at Worldtempus.com</ref>; 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 to the movement of the wearer's body. The back-and-forth motion of the winding rotor couples to a ratchet to automatically wind the watch. The spring drives an escapement, which consists of a lever that moves back and forth against a gear, keeping the gear moving at a specific number of times per second, usually four or five. That gear, in turn, drives all of the other gears of the watch that turn the hands on the dial.
[edit] Batteries
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. It used a battery as its source of electrical power.
Batteries for watches are specially designed for their purpose. They are very small and provide tiny amounts of power continuously for very long periods (a year 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 waterproof, as special tools and procedures are required to ensure that the watch remains waterproof after battery replacement. Silver-oxide and lithium batteries are popular today; mercury batteries, formerly quite common, are no longer used, for environmental reasons.
[edit] Light-powered watches
Some electronic watches are powered by light. A photovoltaic cell on the face 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 battery or capacitor. As long as the watch is regularly exposed to fairly strong light (such as sunlight), it never needs battery replacement.
[edit] Kinetic power
Some movements are 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 in turn, turns a generator to supply power. The concept is similar to that of self-winding spring movements, except that electrical power is generated instead of mechanical motion alone.
[edit] Thermal power
A seldom used power source is the temperature difference between the wearer's arm and the surrounding environment (as applied in the Citizen Eco Drive Thermo).
[edit] Displaying the time
There are two main ways in which watches display the time to their owners: analog and digital.
[edit] Analog display
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. This hand may move smoothly around the face of the watch or it may snap from one second mark to the next; the latter is much more common than the former. All of the hands are normally mechanical, 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.).
[edit] Digital display
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., 10:30 AM instead of a short hand pointing towards the number 10 and a long hand pointing towards the number 6 on a dial.
Cheaper electronics permitted the popularization of the digital watch (an electronic watch with a numerical, rather than analog, display) in the second half of the 20th century. They were seen as the great new thing. Douglas Adams, in the introduction of his novel The Hitchhiker's Guide to the Galaxy, would say that humans were 'so amazingly primitive that they still think digital watches are a pretty neat idea'.
The first digital watch, a Pulsar prototype in 1970, was developed jointly by Hamilton Watch Company and Electro-Data. A retail version of the Pulsar was put on sale in 1972. 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.<ref>[1]</ref> 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. 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.<ref>Gruen Teletime LCD Watch</ref><ref>Casio TA-1000 Electronic Clock & Calculator</ref>
Digital watches did not replace analog watches. In fact, after a number of years of great popularity, digital watches fell somewhat out of fashion, and today most watches display the time in analog form, with mechanical hands, even if all the internal parts of the watch are electronic.
Almost all watches with digital displays today are in the category of simple timekeeping watches, and they are particularly popular with “geek watches” that incorporate a very large number of features besides simply showing the date and time. Watches sold as jewelry or collectibles almost never have digital displays (perhaps in part because they are usually entirely mechanical).
[edit] Watch 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.
[edit] Complicated watches
A complicated watch has one or more functionalities beyond basic time-keeping capabilities; 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. Among watch enthusiasts, complicated watches are especially collectible.
[edit] Chronographs and chronometers
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 is a 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.
[edit] Fashionable watches
At the end of the 20th century, Swiss watch makers were seeing their sales go down as analog clocks were considered obsolete. They joined forces with designers from many countries to reinvent the Swiss watch.
The result was that they could considerably reduce the pieces and production time of an analog watch. In fact it was so cheap that if a watch broke it would be cheaper to throw it away and buy a new one than to repair it. They founded the Swiss Watch company (Swatch) and called graphic designers to redesign a new annual collection.
This is often used as a case study in design schools to demonstrate the commercial potential of industrial and graphic design.
[edit] Collectible and jewelry watches
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, without any pretense at being accurate for telling the time. 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.
Most companies that produce watches specialize in one of these markets. Companies such as Rolex or Chopard specialize in watches as jewelry or fine mechanical devices. Companies such as Casio specialize in watches as timepieces or multifunctional computers. Since watches are considered by many to be both functional and attractive, there are many types and manufacturers to choose from.
[edit] Advanced watches
Many technological enhancements to wristwatches have been explored but most of them remained unnoticed. In 2005 for example, one company marketed an alarm wristwatch with an accelerometer inside that monitors the user's sleep and rings during one of his almost-awake phases.
A number of functionalities not directly related to time have also been inserted into watches. As miniaturized electronics became cheaper, watches have been developed containing calculators, video games, digital cameras, keydrives, GPS receivers and cellular phones. In the early 1980s Seiko marketed a watch with a television receiver in it, although at the time television receivers were too bulky to fit in a wristwatch, and the actual receiver and its power source were in a book-sized box with a cable that ran to the wristwatch. In the early 2000s, a self-contained wristwatch television receiver came on the market, with a strong enough power source to provide one hour of viewing.
These watches have not had sustained long-term sales success. As well as awkward user interfaces due to the tiny screens and buttons possible in a wearable package, and in some cases short battery life, the functionality available has not generally proven sufficiently compelling to attract buyers. Such watches have also had the reputation as ugly and thus mainly geek toys. Now with the ubiquity of the mobile phone in many countries, which have bigger screens, buttons, and batteries, interest in incorporating extra functionality in watches seems to have declined.
Several companies have however attempted to develop a computer contained in a WristWatch (see also wearable computer). As of 2005, the only programmable computer watches to have made it to market are the Seiko Ruputer, the Matsucom onHand, and the Fossil, Inc. Wrist PDA, although many digital watches come with extremely sophisticated data management software built in.
[edit] Spacewatches
Zero gravity environment and other extreme conditions encountered by astronauts in deep space requires the use of specialy designed waches. Chinese taikonauts for example wear the Fiyta [2] spacewatches (飞亚达太空腕表).
[edit] Mobile phones as pocket watches
In the early 2000s, the carrying of mobile telephones has become ubiquitous in many affluent and even some developing countries. As these phones typically display the time on their screens when not in use, it has become common to rely on them for time-keeping, effectively making the mobile phone serve the function of a pocket watch.
[edit] See also
- Clock
- List of watch manufacturers
- Horology
- Chronometer
- Wearable computer
- Calculator watch
- National Association of Watch and Clock Collectors
- 10:08 - The time to which most watches are set in advertisements
- Parts of a mechanical watch mechanism: escapement, balance wheel, tourbillon
[edit] External links
- Chronocentric, non-commercial site containing a very large collection of articles about watches
- LED Watches online - includes Pulsar, HP, National Semiconductor, and other LED and early LCD watch photos
- Project Horologer watch database
- UK patent GB218487, Improvements relating to wrist watches, 1923 patent resulting from John Hardwood's invention of a practical self-winding watch mechanism
- Watch Straps
[edit] References
<references/>cs:Hodinky da:Ur (kronometer) de:Armbanduhr fr:montre (horlogerie) io:Horlojo id:Jam tangan it:Orologio ja:腕時計 pt:Relógio de pulso zh:手表
