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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 As technology progressed, the mechanisms used to measure time have, in some cases, been replaced by use of quartz vibrations or electromagnetic pulses.^[1] The first digital electronic watch was developed in 1970.^[2]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

Judson Laipply
Laipply at Blog World Expo 2008
Born	1976 (age 35–36)
Residence	Lakewood, Ohio[1]
Nationality	American
Other names	Jud Laipply
Years active	2006–present
Known for	Motivational speaking, Comedy, Dance
Notable work(s)	Evolution of Dance (video)[2] Evolution of Dance 2 (video)[3] Might as Well Dance (book)[4]
Website
TheEvolutionOfDance.com MightAsWellDance.com

Judson Laipply (born 1976) is an American motivational speaker and dancer from Bucyrus, Ohio.^[5] He is best known for his performance in the Evolution of Dance viral video clip.^[6] He has worked as a public speaker since 2000.^[1]

The Evolution of Dance[link]

Laipply first performed "The Evolution of Dance" in March 2001, at which time it consisted of 12 popular dance songs. In 2006, he uploaded a video of the six-minute performance to YouTube. The clip received 70 million views in under 8 months.^[7] It was rated on YouTube as:^[8]

• #1 Most Viewed All Time Video on YouTube.com
• #1 Top Rated Video on YouTube.com
• #3 Most Discussed Video on YouTube.com

Songs in Evolution of Dance[link]

Evolution of Dance 2[link]

The Evolution of Dance 2 video was released in January 2009.^[3]

Evolution of Dance 3[link]

This was announced by Judson on June 16, 2010.^[11] He stated that it was in its early stages and that it was too early to give any details. In a YouTube comment he claimed he was trying to incorporate much older music and possibly include a second dancer. In a talk given at TASC (April 2nd) he displayed his new dance. It contains new tracks such as LMFAO's "I'm sexy and I know it" and "Party Rock anthem" as well as other dances such as the "Stanky leg".

Popular culture[link]

In December 2007, Judson appeared in an advert on the BBC for the 'dance season' during the Christmas Holidays.^[12] "Evolution of Dance" was #1 on the show Rude Tube hosted by Alex Zane and Laipply was interviewed on the show. Judson was also featured in the music video for Weezer's song "Pork and Beans" along with several other Internet celebrities.

In February 2010 the video was used as a question reference on the game show Jeopardy! in the 2010 college championships. In "The Delivery" episode of The Office, Andy Bernard does the dance sans music as a pregnancy distraction for Pam. In 2011 Judson also appeared on Tosh.0, hosted by Daniel Tosh.

He did another video, called "The Evolution of the Touchdown Dance", which included memorable NFL touchdown dances, like "The Ickey Shuffle", Joe Horn's cell phone celebration, and famous celebrations from Terrell Owens and Chad Ochocinco.^{[citation needed]}

References[link]

External links[link]

• Official Website
• YouTube page
• Evolution of Dance video, and Judson interviewed for StayTunedTV.tv
• Evolution of Dance on VidTaggr - The Evolution of Dance video labeled with song titles.

Randy Pausch
Randy Pausch
Born	(1960-10-23)October 23, 1960 Baltimore, Maryland, US
Died	July 25, 2008(2008-07-25) (aged 47) Chesapeake, Virginia, United States Pancreatic cancer
Nationality	American
Fields	Computer science Human Computer Interaction
Institutions	Carnegie Mellon University University of Virginia
Alma mater	Brown University Carnegie Mellon University
Doctoral advisor	Alfred Spector
Known for	Creator of Alice software project Cofounder of CMU's Entertainment Technology Center Virtual Reality Research with Disney Imagineers Inspirational speeches regarding life #1 best-selling book Battle with cancer
Notable awards	Karl V. Karlstrom Outstanding Educator Award ACM Special Interest Group on Computer Science Education Award for Outstanding Contributions to Computer Science Education Fellow of the ACM Time's Time 100[1]
Spouse	Jai Glasgow

Randolph Frederick "Randy" Pausch^[2] (October 23, 1960 – July 25, 2008) was an American professor of computer science and human-computer interaction and design at Carnegie Mellon University (CMU) in Pittsburgh, Pennsylvania.

Pausch learned that he had pancreatic cancer in September 2006, and in August 2007 he was given a terminal diagnosis: "3 to 6 months of good health left". He gave an upbeat lecture titled "The Last Lecture: Really Achieving Your Childhood Dreams" on September 18, 2007, at Carnegie Mellon, which became a popular YouTube video and led to other media appearances. He then co-authored a book called The Last Lecture on the same theme, which became a New York Times best-seller.

Pausch died of complications from pancreatic cancer on July 25, 2008.

Early life[link]

Pausch was born in Baltimore, Maryland, and grew up in Columbia, Maryland.^[2] After graduating from Oakland Mills High School in Columbia, Pausch received his bachelor's degree in computer science from Brown University in May 1982 and his Ph.D. in computer science from Carnegie Mellon University in August 1988.^{[3][not in citation given]} While completing his doctoral studies, Pausch was briefly employed at Xerox Palo Alto Research Center and Adobe Systems.^[4]

Computer science career[link]

Pausch was an assistant and associate professor in the Department of Computer Science at the University of Virginia's School of Engineering and Applied Science from 1988 until 1997. While there, he completed sabbaticals at Walt Disney Imagineering and Electronic Arts (EA). In 1997, Pausch became Associate Professor of Computer Science, Human-Computer Interaction and Design, at Carnegie Mellon University. He was a co-founder in 1998, along with Don Marinelli, of CMU's Entertainment Technology Center (ETC), and he started the Building Virtual Worlds^[5] course at CMU and taught it for 10 years. He consulted with Google on user interface design and also consulted with PARC, Imagineering, and Media Metrix.^[4] Pausch is also the founder of the Alice software project.^[6] He received the National Science Foundation Presidential Young Investigator Award and was a Lilly Foundation Teaching Fellow.^[7] Pausch was the author or co-author of five books and over 70 articles.

Pausch received two awards from ACM in 2007 for his achievements in computing education: the Karl V. Karlstrom Outstanding Educator Award and the ACM Special Interest Group on Computer Science Education Award for Outstanding Contributions to Computer Science Education.^[8] He was also inducted as a Fellow of the ACM in 2007.

Cancer and death[link]

Pausch was diagnosed with pancreatic cancer^[9][10] and underwent a Whipple procedure (pancreaticoduodenectomy) on September 19, 2006, in an unsuccessful attempt to halt his pancreatic cancer.^[11] He was told in August 2007 to expect a remaining three to six months of good health. He soon moved his family to Chesapeake, Virginia, a suburb near Norfolk, to be close to his wife's family. On March 13, 2008, Pausch advocated for greater federal funding for pancreatic cancer before the United States Senate Appropriations Subcommittee on Labor, Health and Human Services, Education, and Related Agencies.^[12] In the week prior to this, he had been hospitalized in order to have needle aspiration of pleural effusion in his right lung.^[13]

On May 2, 2008, a positron emission tomography (PET) scan showed that he had very tiny (5 millimetres (0.20 in) or less) metastases in his lungs and some lymph nodes in his chest. He also had some metastases in his peritoneal and retroperitoneal cavities. On June 26, 2008, Pausch indicated that he was considering stopping further chemotherapy because of the potential adverse side effects. He was, however, considering some immuno-therapy-based approaches.^[14] On July 24, on behalf of Pausch, a friend anonymously posted a message on Pausch's webpage stating that a biopsy had indicated that the cancer had progressed further than what was expected from recent PET scans and that Pausch had "taken a step down" and was "much sicker than he had been". The friend also stated that Pausch had then enrolled in a hospice program designed to provide palliative care to those at the end of life.^[14]

Wikinews has related news: "Last Lecture" Professor Randy Pausch dies at age 47

Pausch died from pancreatic cancer at his family's home in Chesapeake, Virginia on July 25, 2008, at the age of 47. He is survived by his wife, Jai, and their three children, Dylan, Logan, and Chloe.^[15]

[edit] Really Achieving Your Childhood Dreams

Pausch delivered his "Last Lecture", titled Really Achieving Your Childhood Dreams, at CMU on September 18, 2007.^[16] He gave an abridged version of his speech on the Oprah show in October 2007.^[17][18] The talk was modeled after an ongoing series of lectures where top academics are asked to think deeply about what matters to them, and then give a hypothetical "final talk", with a topic such as "what wisdom would you try to impart to the world if you knew it was your last chance?" Before speaking, Pausch received a long standing ovation from a large crowd of over 400 colleagues and students. When he motioned them to sit down, saying, "Make me earn it," someone in the audience shouted back, "You did!"^[9][19]

During the lecture, Pausch was upbeat and humorous, alternating between wisecracks, insights on computer science and engineering education, advice on building multi-disciplinary collaborations, working in groups and interacting with other people, offering inspirational life lessons, and performing push-ups on stage. He also commented on the irony that the "Last Lecture" series had recently been renamed as "Journeys", saying, "I thought, damn, I finally nailed the venue and they renamed it."^[15] After Pausch finished his lecture, Steve Seabolt, on behalf of Electronic Arts—which is now collaborating with CMU in the development of Alice 3.0^[20]—pledged to honor Pausch by creating a memorial scholarship for women in computer science, in recognition of Pausch's support and mentoring of women in CS and engineering.^[9]

CMU president Jared Cohon spoke emotionally of Pausch's humanity and called his contributions to the university and to education "remarkable and stunning".^[21] He then announced that CMU will celebrate Pausch's impact on the world by building and naming after Pausch a raised pedestrian bridge^[22] to connect CMU's new Computer Science building and the Center for the Arts, symbolizing the way Pausch linked those two disciplines. Brown University professor Andries van Dam followed Pausch's last lecture with a tearful and impassioned speech praising him for his courage and leadership, calling him a role model.^[21][23][24]

The Randy Pausch Memorial Footbridge was dedicated on October 30, 2009, with Jai, Dylan, Logan and Chloe Pausch cutting the ribbon.

[edit] The Last Lecture

The Disney-owned publisher Hyperion paid $6.7 million for the rights to publish a book about Pausch called The Last Lecture, co-authored by Pausch and Wall Street Journal reporter Jeffrey Zaslow.^[25] The book became a New York Times best-seller on April 28, 2008.^[26] The Last Lecture expands on Pausch's speech. The book's first printing had 400,000 copies, and it has been translated into 46 languages. It has spent more than 85 weeks on The New York Times bestseller list, and there are now more than 4.5 million copies in print in the U.S. alone. Despite speculation that the book would be made into a movie, Pausch had denied these rumors, stating that "there's a reason to do the book, but if it's telling the story of the lecture in the medium of film, we already have that."^[27]

Media coverage[link]

Pausch was named "Person of the Week" on ABC's World News with Charles Gibson on September 21, 2007.^[28] His "Last Lecture" attracted wide attention from the international media,^[29] became an Internet hit, and was viewed over a million times in the first month after its delivery.^[30] On October 22, 2007, Pausch appeared on The Oprah Winfrey Show where he discussed his situation and summarized his "Last Lecture".^[18] On October 6, 2007, Pausch joined the Pittsburgh Steelers for the day during their regular practice, after the organization learned that one of his childhood dreams mentioned in his "Last Lecture" was to play in the NFL.^[31] On April 9, 2008, the ABC network aired an hour long Diane Sawyer feature on Pausch titled "The Last Lecture: A Love Story For Your Life".^[32][33] On July 29, 2008, ABC aired a follow up to the Last Lecture special, remembering Pausch and his famous lecture.^[34]

Other lectures and appearances[link]

Pausch gave a lecture about time management^[35] on November 27, 2007 at the University of Virginia, to an audience of over 850 people.^[36] In March 2008, Pausch appeared in a public service announcement video^[37] and testified before Congress in support of cancer research.^[38] On May 18, 2008, Pausch made a surprise return appearance at Carnegie Mellon, giving a speech at the commencement ceremony,^[39] as well as attending the School of Computer Science's diploma ceremony,^[40] and on May 19 Pausch appeared on the Good Morning America show.^[41] His lecture, "Really Achieving Your Childhood Dreams", was nominated at the 2007 YouTube Video Awards.^[42][43]

A devoted Star Trek fan, Pausch was invited by film director J. J. Abrams to film a role in Star Trek. Abrams heard of Pausch's condition and sent a personal e-mail inviting Pausch to the set. Pausch accepted and traveled to Los Angeles, California to shoot his scene. In addition to appearing in the film, he also has a line of dialogue at the beginning of the film ("Captain, we have visual.") and donated the $217.06 paycheck to charity.^[44][45]

Honors[link]

• The Pittsburgh City Council declared November 19, 2007 to be "Dr. Randy Pausch Day".^[46]
• In May 2008, Pausch was listed by Time as one of the World's Top-100 Most Influential People.^[1]
• Randy was named Pittsburgher of the Year 2008.^[47]
• On May 30, 2008, Randy received a letter from then President George W. Bush thanking him for his commitment to the Nation's youth.^[48]
• On February 4, 2009, The Walt Disney Company dedicated a tribute plaque at Walt Disney World near the "Mad Tea Party" attraction with a quote by Randy that reads "Be good at something; It makes you valuable ... Have something to bring to the table, because that will make you more welcome."^[49]
• The Walt Disney Company also created the Disney Memorial Pausch Fellowship at Carnegie Mellon University, which will support two graduate students.^[50]
• Per Jared Cohon's announcement on the day of the Last Lecture, a raised pedestrian bridge at CMU that connects the Gates Computer Science building and the Purnell Center for the Arts is named after Pausch, symbolizing the way he linked the two disciplines.^[22]

Other publications[link]

• Adding input and output to the transactional model (Research paper, CMU), 1988
• Dann, Wanda P.; Cooper, Stephen; Pausch, Randy (2005-07-25). Learning to Program with Alice. Prentice Hall. ISBN 0-13-187289-3. http://www.aliceprogramming.net/. 
• Pausch, Randy (2008-08-07). Time Management. ISBN 0-9820556-3-3.