Watch

During most of their history, beginning in the 16th century, watches were mechanical devices, driven by clockwork, powered by winding a mainspring, and keeping time with an oscillating balance wheel.

[citation needed] The first timepieces to be worn, made in the 16th century beginning in the German cities of Nuremberg and Augsburg, were transitional in size between clocks and watches.

[16] The increased accuracy of the balance wheel focused attention on errors caused by other parts of the movement, igniting a two-century wave of watchmaking innovation.

Improvements in manufacturing – such as the tooth-cutting machine devised by Robert Hooke – allowed some increase in the volume of watch production, although finishing and assembling was still done by hand until well into the 19th century.

The lever escapement, the single most important technological breakthrough, though invented by Thomas Mudge in 1754[17] and improved by Josiah Emery in 1785,[18] only gradually came into use from about 1800 onwards, chiefly in Britain.

In the United States, Aaron Lufkin Dennison started a factory in 1851 in Massachusetts that used interchangeable parts, and by 1861 a successful enterprise operated, incorporated as the Waltham Watch Company.

[25][26] Wristwatches were first worn by military men towards the end of the 19th century, having increasingly recognized the importance of synchronizing maneuvers during war without potentially revealing plans to the enemy through signaling.

In 1904, Louis Cartier produced a wristwatch to allow his friend Alberto Santos-Dumont to check flight performance in his airship while keeping both hands on the controls as this proved difficult with a pocket watch.

[32] The impact of the First World War of 1914–1918 dramatically shifted public perceptions on the propriety of the man's wristwatch and opened up a mass market in the postwar era.

Service watches produced during the war were specially designed for the rigors of trench warfare, with luminous dials and unbreakable glass.

Compared to electronic movements, mechanical watches are less accurate, often with errors of seconds per day; are sensitive to position, temperature,[52] and magnetism;[53] are costly to produce; require regular maintenance and adjustments; and are more prone to failures.

The task of converting electronically pulsed fork vibration into rotary movements is done via two tiny jeweled fingers, called pawls.

[59] Ten years after its introduction, it is still the only mechanical movement manufactured entirely on a fully automated assembly line, including adjustment of the balance wheel and the escapement for accuracy by laser.

A varying electric voltage is applied to the crystal, which responds by changing its shape so, in combination with some electronic components, it functions as an oscillator.

Most quartz movements are primarily electronic but are geared to drive mechanical hands on the face of the watch to provide a traditional analog display of the time, a feature most consumers still prefer.

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.

[62] In 1970, 18 manufacturers exhibited production versions of the beta 21 wristwatch, including the Omega Electroquartz as well as Patek Philippe, Rolex Oysterquartz and Piaget.

The first quartz watch to enter production was the Seiko 35 SQ Astron, which hit the shelves on 25 December 1969, swiftly followed by the Swiss Beta 21, and then a year later the prototype of one of the world's most accurate wristwatches to date: the Omega Marine Chronometer.

For quartz wristwatches, subsidiaries of Swatch manufacture watch batteries (Renata), oscillators (Oscilloquartz, now Micro Crystal AG) and integrated circuits (Ebauches Electronic SA, renamed EM Microelectronic-Marin).

[66] 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).

Digital displays often show a time of 12:08, where the increase in the number of active segments or pixels gives a positive feeling.

[67][68] Tissot, a Swiss luxury watchmaker, makes the Silen-T wristwatch with a touch-sensitive face that vibrates to help the user to tell time eyes-free.

The Quarza, introduced in 1972 had the first Field Effect LCD readable in direct sunlight and produced by the International Liquid Crystal Corporation of Cleveland, Ohio.

Since their apex during the late 1980s to mid-1990s high technology fad, digital watches have mostly become simpler, less expensive timepieces with little variety between models.

Wristwatches with analog displays generally have a small knob, called the crown, that can be used to adjust the time and, in mechanical watches, wind the spring.

A chronograph is a watch with an added duration timer, often a stopwatch complication (as explained above), while a chronometer watch is a timepiece that has met an industry-standard test for performance under pre-defined conditions: a chronometer is 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).

Many fashions 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.

The Omega Speedmaster Professional was selected by NASA, the U.S. space agency, and it is mostly known thanks to astronaut Buzz Aldrin who wore it during the 1969 Apollo 11 Moon landing.

At BaselWorld, 2008, Seiko announced the creation of the first watch ever designed specifically for a space walk, Spring Drive Spacewalk.

In the United States, advertising a watch as waterproof has been illegal since 1968, per Federal Trade Commission regulations regarding the "misrepresentation of protective features".