title: Diesel exhaust fluid

text: Several brands of SCR systems use DEF: BlueHDI is used by PSA Group vehicles including Peugeot, Citroën, and DS Automobiles brands; BlueTec by Daimler AG; and FLENDS (Final Low Emission New Diesel System) by UD Trucks.


title: Diesel exhaust fluid

text: Diesel engines are typically operated with a lean burn air-to-fuel ratio (over-stoichiometric ratio) to ensure the full combustion of soot and to prevent them from exhausting unburnt fuel. The excess air leads to the generation of , which are harmful pollutants, from nitrogen in the atmosphere. SCR is used to reduce the amount of released into the atmosphere. DEF from a separate tank is injected into the exhaust pipeline, and the exhaust heat decomposes it to ammonia. Within the SCR catalyst, the are reduced by the ammonia into water and nitrogen, which are both non-polluting. The water and nitrogen are then released into the atmosphere through the exhaust.


title: Diesel exhaust fluid

text: SCR was applied to automobiles by Nissan Diesel Corporation, and the first practical product "Nissan Diesel Quon" was introduced in 2004. With the cooperation of the oil and chemical industry, a 1,300-station infrastructure to supply DEF was prepared by September 2005 in Japan.


title: Diesel exhaust fluid

text: In 2007, the United States Environmental Protection Agency (EPA) enacted requirements to significantly reduce harmful exhaust emissions. To achieve this standard, Cummins and other diesel engine manufacturers developed an aftertreatment system that includes the use of a diesel particulate filter (DPF).


title: Diesel exhaust fluid

text: As the DPF does not function with low-sulfur diesel fuel, diesel engines that conform to 2007 EPA emissions standards require ultra-low-sulfur diesel (ULSD) fuel to prevent damage to the DPF. After a brief transition period, ULSD fuel became common at fuel pumps in the United States and Canada.


title: Diesel exhaust fluid

text: The 2007 EPA regulations were meant to be an interim solution to allow manufacturers time to prepare for the more stringent 2010 EPA regulations, which reduced levels even further. In 2008, the concerns about compliance shifted to the infrastructure for DEF distribution.


title: Diesel exhaust fluid

text: The injection rate of DEF into the exhaust depends on the specific after-treatment system, but is typically 2–6% of diesel consumption volume. This low dosing rate ensures long fluid refill intervals and minimizes the tank's size and intrusion into vehicle packaging space. An electronic control unit adjusts the addition of fluid in accordance with parameters such as NOx level in exhaust gas (before catalytic converter, after catalytic converter, and possibly between catalytic converters if there is more than one), current ammonia filling level, engine operating temperature and speed.


title: Diesel exhaust fluid

text: DEF is a 32.5% solution of urea, . When it is injected into the hot exhaust gas stream, the water evaporates and the urea thermally decomposes to form ammonia () and isocyanic acid (HNCO):


title: Diesel exhaust fluid

text: The ratio between and determines which reactions take place how fast. The highest conversion rates are achieved if equal amounts of and are present, especially at temperatures between 200°C and 350°C. If there is more than , fast SCR and standard SCR take place sequentially. If there is more than , fast SCR and NO SCR take place sequentially, however, NO SCR is slower than standard SCR, and ammonia nitrate can form and temporarily deactivate the catalytic converter.


title: Diesel exhaust fluid

text: DEF freezes at . For the SCR exhaust cleaning system to function at low temperatures, a sufficient amount of the frozen DEF must be melted in as short time as possible, preferably on the order of minutes. For example, 2010 EPA emissions requirements require full DEF coolant flow within 70 minutes.


title: Diesel exhaust fluid

text: In Europe, specified in Annex XVI point 10 that DEF from a frozen tank at a core temperature of -15°C must become available within 20 minutes when starting the engine at -15°C.


title: Diesel exhaust fluid

text: Typically, the frozen DEF is melted by heat from the engine, e.g. engine coolant passing through the DEF tank, governed by a thermostatic coolant control valve. This method may take significant time before the SCR exhaust cleaning system is fully operational, often up to an hour.


title: Diesel exhaust fluid

text: Another method to thaw DEF (and thus allow for full SCR operation) is to integrate an electrical heater into the DEF tank. This heater must be sized, positioned, and powered adequately to rapidly melt sufficient frozen DEF. It should preferably be self-regulating not to overheat if (part of) the heater is outside of the liquid. It should also preferably be self-regulating to eliminate any complicated sensor and temperature regulating systems. Furthermore, the heater should not exceed , as DEF begins to decompose at around . PTC heaters are often used to achieve this.


title: Diesel exhaust fluid

text: The urea solution is clear, non-toxic and safe to handle. Since urea has corrosive impact on metals like aluminium, DEF is stored and transported in special containers. These containers are typically made of stainless steel. Vehicles' selective catalytic reduction (SCR) systems and DEF dispensers are designed in a manner that there is no corrosive impact of urea on them. It is recommended that DEF be stored in a cool, dry, and well-ventilated area that is out of direct sunlight. Bulk volumes of DEF are compatible for storage within polyethylene containers (HDPE, XLPE), fiberglass reinforced plastic (FRP), and steel tanks. DEF is also often handled in intermediate bulk containers for storage and shipping.


title: Diesel exhaust fluid

text: DEF is offered to consumers in a variety of quantities ranging from containers for single or repeated small usage, up to bulk carriers for consumers requiring a large amount of DEF. As of 2013, many truck stops have added DEF pumps. These are usually adjacent to fuel pumps so the driver can fill both tanks without moving the truck.


title: Diesel exhaust fluid

text: In Europe, increasing numbers of fuel stations offer AdBlue pumps, not only for large commercial vehicles but also for passenger cars.


title: Diesel exhaust fluid

text: At airports, where DEF can sometimes be required for diesel ground service vehicles, its labelling and storage must be carefully managed to avoid accidentally servicing jet aircraft with DEF instead of fuel system icing inhibitor, a mistake that has been attributed to multiple in-flight engine failure and grounding incidents.


title: Diesel exhaust fluid

text: As most of the urea used is supplied by China, imports have slowed since China introduced mandatory inspections of urea exports in September.


title: Diesel exhaust fluid

text: Nearly 97% of South Korea's urea imports came from China between January and September. In 2015, South Korea had made it mandatory for diesel cars to use urea solutions to control emissions, a move that now impacts 40% of registered vehicles. Diesel vehicles made since 2015 were required to be fitted with SCR systems. The South Korean government started rationing urea solution, and banned its resale as panic buying by drivers exacerbated an acute shortage that could cause transport and industry to grind to a halt.


title: Diesel exhaust fluid

text: In early December 2021, the Australian National Road Transport Association also raised concerns about a shortage of DEF in the country due to the shortage of urea in China. China capped exports to protect its domestic supplies and rising DEF prices. By mid-December there was approximately 7 weeks’ supply of AdBlue left in Australia.


title: Mannequin (1987 film)

text: Mannequin is a 1987 American romantic comedy film directed by Michael Gottlieb in his directional debut, and written by Edward Rugoff and Gottlieb. It stars Andrew McCarthy, Kim Cattrall, Estelle Getty, Meshach Taylor and G. W. Bailey. The original music score was composed by Sylvester Levay. A modern retelling of the Pygmalion myth, the film revolves around a chronically underemployed passionate artist named Jonathan Switcher who lands a job as a department-store window dresser and the mannequin he created which becomes inhabited by the spirit of a woman from Ancient Egypt, but only comes alive for Jonathan.


title: Mannequin (1987 film)

text: "Mannequin" received a nomination for an Academy Award for Best Original Song for its main title song, "Nothing's Gonna Stop Us Now" by Starship, which reached number one on both the "Billboard" Hot 100 and UK Singles Chart. In 1991, a sequel to the film called "" was released. Though the sequel takes place in the same department store in Philadelphia, only actors Meshach Taylor and Andrew Hill Newman returned from the original film.


title: Mannequin (1987 film)

text: In Ancient Egypt, Ema "Emmy" Hesire takes refuge in a pyramid, pleading to the gods that she find true love rather than enter an arranged marriage. Emmy suddenly vanishes before her mother's eyes. In 1987 Philadelphia, Jonathan Switcher is a sculptor working at a mannequin warehouse and finishes a single female mannequin he considers a masterpiece. His boss fires him for spending time trying to make his mannequins works of art rather than assembling several each day.


title: Mannequin (1987 film)

text: Jonathan takes a number of odd jobs and is fired each time for working too slowly because he tries to make each project artistic. His girlfriend Roxie Shield, an employee of the Illustra department store, dumps him, criticizing him as a flake. After his motorcycle breaks down in the rain, Jonathan passes the Prince & Company department store. Seeing his mannequin in the display window, he remarks she is the first work that made him feel like a true artist. The next morning, he saves store owner Claire Timkin from being injured by her own shop sign. Grateful, Claire orders store manager Mr. Richards (who is secretly paid by Illustra to sabotage Prince & Company so it can be bought) to give Jonathan a job. Viewed with suspicion by security guard Captain Felix Maxwell, Jonathan works with and befriends window dresser Hollywood Montrose. When Jonathan is putting together a window display, the mannequin he made comes to life with Emmy's spirit. She says she has existed for centuries as a muse, sometimes inhabiting the works of an artist she admires and inspires. She has encountered amazing people but has never found true love. Emmy explains the gods allow her life when she and Jonathan are unobserved, otherwise she is a mannequin.


title: Mannequin (1987 film)

text: With Emmy's help, Jonathan's window display is a massive success. Now placed in charge of visual merchandising, Jonathan asks Emmy to continue helping with the displays. Over several weeks, they create several popular displays, attracting new business while also deepening their relationship. Montrose realizes Jonathan loves a mannequin he created but doesn't judge him. Illustra's chief executive B.J. Wert sends Roxie to poach Jonathan but he refuses, saying he now works for people who value him. Annoyed by Felix's ineptitude and Richards' attitude towards Jonathan, Claire fires them. Deeply impressed with his work, Claire makes Jonathan vice president of the department store. One night, Jonathan takes Emmy through the city on his motorcycle, despite how unusual this seems to bystanders. He is witnessed by Richards and Felix, who conclude he is deeply fixated on a female mannequin.


title: Mannequin (1987 film)

text: Richards and Felix (who now works for Illustra) steal the female mannequins from Prince & Company. The next morning, Jonathan confronts Wert about the theft, who makes another job offer. Furious over Jonathan caring so much about the mannequin he calls Emmy, Roxie storms off. Jonathan follows Roxie while being pursued by security guards including Felix. Wert and Richards demand the police be called. Roxie loads the stolen mannequins into the store's large trash compactor, then is knocked out by the debris. As Hollywood holds the pursuers at bay with a fire hose, a janitor watches Jonathan jump onto the compactor's conveyor belt to save the mannequin that is Emmy. As Jonathan risks his life for her, Emmy comes to life. Once safe, she realizes she is truly and permanently alive again. Emmy thanks the gods for uniting her with her true love and Jonathan promises to love her forever.


title: Mannequin (1987 film)

text: While the janitor wonders if other mannequins will come to life, Hollywood arrives and realizes Emmy was alive the entire time. Felix and his fellow guards rush in, followed by Wert and Richards who demand the police arrest Jonathan. Claire arrives, revealing she has security video of Richards and Felix breaking and entering, and committing theft. She accuses Wert of conspiracy, and Jonathan adds the man also kidnapped Emmy. Wert fires Roxie as he is arrested and hauled away alongside Richards and Felix. Jonathan realizes the security footage may have shown him being romantic with a mannequin, but Claire coyly suggests he shouldn't worry about that. Some time later, Jonathan and Emmy are married in the store window of Prince & Company, with Claire as maid of honor and Hollywood as best man. Numerous pedestrians outside the store window applaud the wedding.


title: Mannequin (1987 film)

text: The idea for the film came when director Michael Gottlieb was walking down Fifth Avenue and thought he saw a mannequin move in the window of Bergdorf Goodman. Others observe the similarities to the plot of the film "One Touch of Venus" (1948) and to the myth of Pygmalion, who sculpted a statue that came to life when he fell in love. There's also a song from the TV series 'Fame' that sees a dancer singing with a mannequin that comes to life.


title: Mannequin (1987 film)

text: The film was made based on the marketing principles of noted Hollywood market researcher Joseph Farrell, who served as an executive producer. The film was specifically designed to appeal to target demographics. Though not a star, McCarthy was cast after tests of his films showed that he strongly appealed to girls, the target audience.


title: Mannequin (1987 film)

text: The producers contacted various state film commissions across America looking for an elegant center city department store in which to shoot the movie. They visited stores across the country before settling on John Wanamaker's in Philadelphia (now Macy's Center City). The store was given the name Prince and Company for the film. Interior filming at Wanamaker's took about three weeks, with shooting usually beginning around 9 pm and going until 6 am the next day.


title: Mannequin (1987 film)

text: Additional scenes were filmed in the formal gardens behind The Hotel Hershey. Scenes taking place at the fictitious department store Illustra were filmed at the Boscov's department store in the former Camp Hill Mall (now Camp Hill Shopping Center) near Harrisburg, Pennsylvania.


title: Mannequin (1987 film)

text: Prior to the start of filming, Cattrall spent six weeks posing for a Santa Monica sculptor, who captured her likeness. Six mannequins, each with a different expression, were made. Cattrall recalled (1987), "There's no way to play a mannequin except if you want to sit there as a dummy [...] I did a lot of body-building because I wanted to be as streamlined as possible. I wanted to match the mannequins as closely as I could." The actress also said that doing the film made her feel "grown up":


title: Mannequin (1987 film)

text: I've become more of a leading lady instead of, like, the girl... All the other movies that I've done I played the girl, and the plot was around the guy. I've never had anybody to do special lighting for me, or find out what clothes look good on me, or what camera angles are best for me... In this movie, I learned a lot from it. It's almost like learning old Hollywood techniques... I've always been sort of a tomboy. I feel great being a girl, wearing a dress.


title: Mannequin (1987 film)

text: Featured in the film, "Nothing's Gonna Stop Us Now" was a song co-written by Albert Hammond and Diane Warren and recorded by the American rock band Starship in 1986. It is a duet featuring Starship vocalists Grace Slick and Mickey Thomas. It reached number one on the "Billboard" Hot 100 on April 4, 1987, and topped the UK Singles Chart for four weeks the following month, becoming the UK's second-biggest-selling single of 1987.


title: Mannequin (1987 film)

text: The film debuted at number three at the US box office behind "Platoon" and "Outrageous Fortune", grossing $6 million over the four-day President's Day weekend, surpassing the other opener, "Over the Top" starring Sylvester Stallone. The film grossed a total of $42.7 million in the United States and Canada.


title: Mannequin (1987 film)

text: On Rotten Tomatoes, the film has an approval rating of 20% based on 40 reviews and an average rating of 3.9/10. The site's consensus states: ""Mannequin" is a real dummy, outfitted with a ludicrous concept and a painfully earnest script that never springs to life, despite the best efforts of an impossibly charming Kim Cattrall." On Metacritic, the film has a score of 21 out of 100 based on reviews from 13 critics, indicating "generally unfavorable reviews". Audiences surveyed by CinemaScore gave the film a grade B+ on scale of A to F.


title: Mannequin (1987 film)

text: It was savaged by Leonard Maltin, who called it "absolute rock-bottom fare, dispiriting for anyone who remembers what movie comedy should be." In his print review, Roger Ebert awarded it a half star and wrote, "A lot of bad movies are fairly throbbing with life. "Mannequin" is dead. The wake lasts 1 1/2 hours, and then we can leave the theater."


title: Mannequin (1987 film)

text: Rita Kempley of "The Washington Post" called the film "made by, for, and about dummies." Janet Maslin of "The New York Times" puts the blame on the writer-director: "as co-written and directed by Michael Gottlieb, "Mannequin" is a state-of-the-art showcase of perfunctory technique."


title: Mannequin (1987 film)

text: Dan McQuade, writing in "Philadelphia Magazine", referencing the film's use of Philadelphia as a setting, after panning the film itself wrote, "The message of "Mannequin", clumsy as it is, is that the greatest place and time in recorded history is 1980s Philadelphia... Truly, this is the most uplifting film ever made about the city."


title: Mannequin (1987 film)

text: David Cornelius of "DVD Talk" wrote: ""Mannequin" is one of the stupidest movies ever conceived, and one of the worst. Which makes it, in its own lousy way, mesmerizing. To watch it is to get sucked in by its hypnotic ways; its very off-the-wall shoddiness is astounding. Spader alone is worth the price of admission – surely aware of the movie's badness, the actor hams it up with a deliriously over-the-top performance." He called it "a Bad Movie Essential" but warned viewers with a lower pain threshold for bad films to "obviously skip it" as it is a dreadful film.


title: Mannequin (1987 film)

text: Despite being savaged by critics, the film made a strong profit (see above). In 1991, a sequel called "" was released and was directed by Stewart Raffill. The sequel was dubbed as "one of the worst follow-ups ever made." The second film featured different main characters but with the same department store setting and with Meshach Taylor reprising his role. Andrew Hill Newman, who played the Compactor Room Janitor in the first time, returns in the sequel as a security guard named Andy Ackerman. It is not explicitly said whether this is a new character entirely or is the original character (who was not named), now working in a different capacity for the same store.


title: Mannequin (1987 film)

text: In 2010, Gladden Entertainment executives were said to be in the "early development" stage of the remake, envisioning a plot of the man crushing on a "laser display hologram" as opposed to a mannequin. However, no further details were made public about its development.


title: Mannequin (1987 film)

text: "Mannequin" was released on VHS, Betamax, and digital stereo LaserDisc format in September 1987 by Cannon Films through Media Home Entertainment. The film was released on DVD by MGM Home Entertainment on October 7, 2004, in a widescreen Region 1 DVD, and was later re-released to DVD on January 16, 2008, in a new double feature edition with "Mannequin Two: On the Move" as the second disc. "Mannequin" was released on Blu-ray for the first time by Olive Films (under license from MGM) on November 3, 2015.


title: Mannequin (1987 film)

text: Kenickie/Rosita bass player Emmy Kate Montrose (born Emma Jackson, 1978) took her stage name from the characters Emmy and Montrose in the film.


title: Shot put

text: The shot put is a track and field event involving "putting" (throwing) a heavy spherical ball—the "shot"—as far as possible. The shot put competition for men has been a part of the modern Olympics since their revival in 1896, and women's competition began in 1948.


title: Shot put

text: Homer mentions competitions of rock throwing by soldiers during the Siege of Troy but there is no record of any dead weights being thrown in Greek competitions. The first evidence for stone- or weight-throwing events were in the Scottish Highlands, and date back to approximately the first century. In the 16th century King Henry VIII was noted for his prowess in court competitions of weight and hammer throwing.


title: Shot put

text: The first events resembling the modern shot put likely occurred in the Middle Ages when soldiers held competitions in which they hurled cannonballs. Shot put competitions were first recorded in early 19th century Scotland, and were a part of the British Amateur Championships beginning in 1866.


title: Shot put

text: Competitors take their throw from inside a marked circle in diameter, with a "toe board" or "stop board" high at the front of the circle. The distance thrown is measured from the inside of the circumference of the circle to the nearest mark made on the ground by the falling shot, with distances rounded down to the nearest centimetre under IAAF and WMA rules.


title: Shot put

text: The following are either obsolete or non-existent, but commonly believed rules within professional competition:


title: Shot put

text: Shot put competitions have been held at the modern Summer Olympic Games since their inception in 1896, and it is also included as an event in the World Athletics Championships.


title: Shot put

text: Each of these competitions in the modern era have a set number of rounds of throws. Typically there are three qualification rounds to determine qualification for the final. There are then three preliminary rounds in the final with the top eight competitors receiving a further three throws. Each competitor in the final is credited with their longest throw, regardless of whether it was achieved in the preliminary or final three rounds. The competitor with the longest legal put is declared the winner.


title: Shot put

text: In open competitions the men's shot weighs , and the women's shot weighs . Junior, school, and masters competitions often use different weights of shots, typically below the weights of those used in open competitions; the individual rules for each competition should be consulted in order to determine the correct weights to be used.


title: Shot put

text: Two putting styles are in current general use by shot put competitors: the "glide" and the "spin". With all putting styles, the goal is to release the shot with maximum forward velocity at an angle of approximately forty-five degrees.


title: Shot put

text: The origin of this technique dates to 1951, when Parry O'Brien from the United States invented a technique that involved the putter facing backwards, rotating 180 degrees across the circle, and then tossing the shot. Unlike spin this technique is a linear movement.


title: Shot put

text: With this technique, a right-hand thrower would begin facing the rear of the circle. They would typically adopt a specific type of crouch, involving their bent right leg, in order to begin the throw from a more beneficial posture whilst also isometrically preloading their muscles. The positioning of their bodyweight over their bent leg, which pushes upwards with equal force, generates a preparatory isometric press. The force generated by this press will be channelled into the subsequent throw making it more powerful. To initiate the throw they kick to the front with the left leg, while pushing off forcefully with the right. As the thrower crosses the circle, the hips twist toward the front, the left arm is swung out then pulled back tight, followed by the shoulders, and they then strike in a putting motion with their right arm. The key is to move quickly across the circle with as little air under the feet as possible, hence the name 'glide'.


title: Shot put

text: This is also known as the rotational technique. It was first practiced in Europe in the 1950s but did not receive much attention until the 1970s. In 1972 Aleksandr Baryshnikov set his first USSR record using a new putting style, the spin ("круговой мах" in Russian), invented by his coach Viktor Alexeyev. The spin involves rotating like a discus thrower and using rotational momentum for power. In 1976 Baryshnikov went on to set a world record of with his spin style, and was the first shot putter to cross the 22-meter mark.


title: Shot put

text: With this technique, a right-hand thrower faces the rear, and begins to spin on the ball of the left foot. The thrower comes around and faces the front of the circle and drives the right foot into the center of the circle. Finally, the thrower reaches for the front of the circle with the left foot, twisting the hips and shoulders like in the glide, and puts the shot.


title: Shot put

text: When the athlete executes the spin, the upper body is twisted hard to the right, so the imaginary lines created by the shoulders and hips are no longer parallel. This action builds up torque, and stretches the muscles, creating an involuntary elasticity in the muscles, providing extra power and momentum. When the athlete prepares to release, the left foot is firmly planted, causing the momentum and energy generated to be conserved, pushing the shot in an upward and outward direction.


title: Shot put

text: Another purpose of the spin is to build up a high rotational speed, by swinging the right leg initially, then to bring all the limbs in tightly, similar to a figure skater bringing in their arms while spinning to increase their speed. Once this fast speed is achieved the shot is released, transferring the energy into the shot put.


title: Shot put

text: Until 2016, a woman had never made an Olympic final (top 8) using the spin technique. The first woman to enter a final and win a medal at the Olympics was Anita Márton.


title: Shot put

text: Currently, most top male shot putters use the spin. However the glide remains popular since the technique leads to greater consistency compared to the rotational technique. Almost all throwers start by using the glide. Tomasz Majewski notes that although most athletes use the spin, he and some other top shot putters achieved success using this classic method (for example he became first to defend the Olympic title in 56 years).


title: Shot put

text: The world record and the next six best male results (23.37, 23.30, 23.15, and 23.12 by Ryan Crouser, 23.23 by Joe Kovacs, and 23.12 and 23.10 by Randy Barnes) were completed with the spin technique, while the eighth-best all-time put of by Ulf Timmermann was completed with the glide technique.


title: Shot put

text: The decision to glide or spin may need to be decided on an individual basis, determined by the thrower's size and power. Short throwers may benefit from the spin and taller throwers may benefit from the glide, but many throwers do not follow this guideline.


title: Shot put

text: The shot is made of different kinds of materials depending on its intended use. Materials used include sand, iron, cast iron, solid steel, stainless steel, brass, and synthetic materials like polyvinyl. Some metals are more dense than others, making the size of the shot vary. For example, different materials are used to make indoor and outdoor shot – because damage to surroundings must be taken into account – so the latter are smaller. There are various size and weight standards for the implement that depend on the age and gender of the competitors as well as the national customs of the governing body.


title: Field hockey

text: Field hockey is a team sport structured in standard hockey format, in which each team plays with ten outfield players and a goalkeeper. Teams must drive a round hockey ball by hitting it with a hockey stick towards the rival team's shooting circle and then into the goal. The match is won by the team that scores the most goals. Matches are played on grass, watered turf, artificial turf, synthetic field, or indoor boarded surface.


title: Field hockey

text: The stick is made of wood, carbon fibre, fibreglass, or a combination of carbon fibre and fibreglass in different quantities. The stick has two sides; one rounded and one flat; only the flat face of the stick is allowed to progress the ball. During play, goalkeepers are the only players allowed to touch the ball with any part of their body. A player's hand is considered part of the stick if holding the stick. If the ball is "played" with the rounded part of the stick (i.e. deliberately stopped or hit), it will result in a penalty (accidental touches are not an offense if they do not materially affect play). Goalkeepers often have a different design of stick; they also cannot play the ball with the round side of their stick.


title: Field hockey

text: The modern game was developed at public schools in 19th century England and it is now played globally. The governing body is the International Hockey Federation (FIH), called the in French. Men and women are represented internationally in competitions including the Olympic Games, World Cup, World League, Champions Trophy and Junior World Cup. Many countries run extensive junior, senior, and masters club competitions. The FIH is also responsible for organizing the Hockey Rules Board and developing the sport's rules. The sport is known simply as "hockey" in countries where it is the more common form of hockey. The term "field hockey" is used primarily in Canada and the United States where "hockey" more often refers to ice hockey. In Sweden, the term "landhockey" is used. A popular variant is indoor field hockey, which differs in a number of respects while embodying the primary principles of hockey.


title: Field hockey

text: According to the International Hockey Federation (FIH), "the roots of hockey are buried deep in antiquity". There are historical records which suggest early forms of hockey were played in Egypt and Persia c. 2000 BC, and in Ethiopia c. 1000 BC. Later evidence suggest that the ancient Greeks, Romans and Aztecs all played hockey-like games. In Ancient Egypt, there is a depiction of two figures playing with sticks and ball in the Beni Hasan tomb of Khety, an administrator of Dynasty XI.


title: Field hockey

text: In Ancient Greece, there is a similar image dated c. 510 BC, which may have been called () because it was played with a horn (, in Ancient Greek) and a ball. Researchers disagree over how to interpret this image. It could have been a team or one-on-one activity (the depiction shows two active players, and other figures who may be team-mates awaiting a face-off, or non-players waiting for their turn at play). Billiards historians Stein and Rubino believe it was among the games ancestral to lawn-and-field games like hockey and ground billiards, and near-identical depictions appear in later European illuminated manuscripts and other works of the 14th through 17th centuries, showing contemporary courtly and clerical life.


title: Field hockey

text: In East Asia, a similar game was entertained, using a carved wooden stick and ball, prior to 300 BC. In Inner Mongolia, China, the Daur people have for about 1,000 years been playing "beikou", a game with some similarities to field hockey. A similar field hockey or ground billiards variant, called "suigan", was played in China during the Ming dynasty (1368–1644, post-dating the Mongol-led Yuan dynasty). A game similar to field hockey was played in the 17th century in Punjab state in India under name "khido khundi" ("khido" refers to the woolen ball, and "khundi" to the stick).


title: Field hockey

text: In South America, most specifically in Chile, the local natives of the 16th century used to play a game called Chueca, which also shares common elements with hockey.


title: Field hockey

text: In Northern Europe, the games of hurling (Ireland) and ' (Iceland), both team ball games involving sticks to drive a ball to the opponents' goal, date at least as far back as the Early Middle Ages. By the 12th century, a team ball game called ' or "", akin to a chaotic and sometimes long-distance version of hockey or rugby football (depending on whether sticks were used in a particular local variant), was regularly played in France and southern Britain between villages or parishes. Throughout the Middle Ages to the Early Modern era, such games often involved the local clergy or secular aristocracy, and in some periods were limited to them by various anti-gaming edicts, or even banned altogether. Stein and Rubino, among others, ultimately trace aspects of these games both to rituals in antiquity involving orbs and sceptres (on the aristocratic and clerical side), and to ancient military training exercises (on the popular side); polo (essentially hockey on horseback) was devised by the Ancient Persians for cavalry training, based on the local proto-hockey foot game of the region.


title: Field hockey

text: The word "hockey" itself has no clear origin. One belief is that it was recorded in 1363 when Edward III of England issued the proclamation: "Moreover we ordain that you prohibit under penalty of imprisonment all and sundry from such stone, wood and iron throwing; handball, football, or hockey; coursing and cock-fighting, or other such idle games". The belief is based on modern translations of the proclamation, which was originally in Latin and explicitly forbade the games "Pilam Manualem, Pedivam, & Bacularem: & ad Canibucam & Gallorum Pugnam". It may be recalled at this point that "baculum" is the Latin for 'stick', so the reference would appear to be to a game played with sticks. The English historian and biographer John Strype did not use the word "hockey" when he translated the proclamation in 1720, and the word 'hockey' remains of unknown origin.


title: Field hockey

text: The modern game developed at public schools in 19th century England. It is now played globally, particularly in parts of Western Europe, South Asia, Southern Africa, Australia, New Zealand, Argentina, and parts of the United States, primarily New England and the mid-Atlantic states. The term "field hockey" is used primarily in Canada and the United States where "hockey" more often refers to ice hockey. In Sweden, the term "landhockey" is used, and to some degree in Norway, where the game is governed by Norges Bandyforbund.


title: Field hockey

text: The first known club was formed in 1849 at Blackheath in south-east London, but the modern rules grew out of a version played by Middlesex cricket clubs as a winter activity. Teddington Hockey Club formed the modern game by introducing the striking circle and changing the ball to a sphere from a rubber cube. The Hockey Association was founded in 1876. It lasted just six years, before being revived by nine founding members. The first international competition took place in 1895 (Ireland 3, Wales 0), and the International Rules Board was founded in 1900.


title: Field hockey

text: Field hockey was played at the Summer Olympics in 1908 and 1920. It was dropped in 1924, leading to the foundation of the Fédération Internationale de Hockey sur Gazon (FIH) as an international governing body by seven continental European nations; and hockey was reinstated as an Olympic game in 1928. Men's hockey united under the FIH in 1970.


title: Field hockey

text: The two oldest trophies are the Irish Senior Cup, which dates back to 1894, and the Irish Junior Cup, a second XI-only competition instituted in 1895.


title: Field hockey

text: In India, the Beighton Cup and the Aga Khan tournament commenced within ten years. Entering the Olympics in 1928, India won all five games without conceding a goal, and won from 1932 until 1956 and then in 1964 and 1980. Pakistan won in 1960, 1968 and 1984.


title: Field hockey

text: In the early 1970s, artificial turf began to be used. Synthetic pitches changed most aspects of field hockey, gaining speed. New tactics and techniques such as the Indian dribble developed, followed by new rules to take account. The switch to synthetic surfaces ended Indian and Pakistani domination because artificial turf was too expensive in developing countries. Since the 1970s, Australia, the Netherlands, and Germany have dominated at the Olympics and World Cup stages.


title: Field hockey

text: Women's field hockey was first played at British universities and schools. The first club, the Molesey Ladies, was founded in 1887. The first national association was the Irish Ladies Hockey Union in 1894, and though rebuffed by the Hockey Association, women's field hockey grew rapidly around the world. This led to the International Federation of Women's Hockey Association (IFWHA) in 1927, though this did not include many continental European countries where women played as sections of men's associations and were affiliated to the FIH. The IFWHA held conferences every three years, and tournaments associated with these were the primary IFWHA competitions. These tournaments were non-competitive until 1975.


title: Field hockey

text: By the early 1970s, there were 22 associations with women's sections in the FIH and 36 associations in the IFWHA. Discussions started about a common rule book. The FIH introduced competitive tournaments in 1974, forcing the acceptance of the principle of competitive field hockey by the IFWHA in 1973. It took until 1982 for the two bodies to merge, but this allowed the introduction of women's field hockey to the Olympic games from 1980 where, as in the men's game, the Netherlands, Germany, and Australia have been consistently strong. Argentina has emerged as a team to be reckoned with since 2000, winning the world championship in 2002 and 2010 and medals at the last three Olympics.


title: Field hockey

text: In the United States, field hockey is played predominantly by girls and women. There are few field hockey clubs, most play taking place between high school or college sides. The sport was largely introduced in the U.S. by Constance Applebee, starting with a tour of Seven Sisters colleges in 1901 and continuing through Applebee's 24-year tenure as athletic director of Bryn Mawr College. The strength of college field hockey reflects the impact of Title IX, which mandated that colleges should fund men's and women's games programmes comparably. Hockey has been predominantly played on the East Coast, specifically the Mid-Atlantic in states such as New Jersey, New York, Pennsylvania, Maryland, and Virginia. In recent years, it has become increasingly played on the West Coast and in the Midwest.


title: Field hockey

text: In other countries, participation is fairly evenly balanced between men and women. For example, in the 2008–09 season, England Hockey reported 2,488 registered men's teams, 1,969 women's teams, 1,042 boys' teams, 966 girls' teams and 274 mixed teams. In 2006, the Irish Hockey Association reported that the gender split among its players was approximately 65% female and 35% male. In its 2008 census, Hockey Australia reported 40,534 male club players and 41,542 female.


title: Field hockey

text: Most hockey field dimensions were originally fixed using whole numbers of imperial measures. Metric measurements are now the official dimensions as laid down by the International Hockey Federation (FIH) in the "Rules of Hockey".


title: Field hockey

text: The pitch is a rectangular field. At each end is a goal high and wide, as well as lines across the field from each end-line (generally referred to as the 23-metre lines or the 25-yard lines) and in the center of the field. A spot in diameter, called the penalty spot or stroke mark, is placed with its centre from the centre of each goal. The shooting circle is from the base line.


title: Field hockey

text: Field hockey goals are made of two upright posts, joined at the top by a horizontal crossbar, with a net positioned to catch the ball when it passes through the goalposts. The goalposts and crossbar must be white and rectangular in shape, and should be wide and deep.


title: Field hockey

text: Field hockey goals also include sideboards and a backboard, which stand from the ground. The backboard runs the full width of the goal, while the sideboards are deep.


title: Field hockey

text: Historically the game developed on natural grass turf. In the early 1970s, synthetic grass fields began to be used for hockey, with the first Olympic Games on this surface being held at Montreal in 1976. Synthetic pitches are now mandatory for all international tournaments and for most national competitions. While hockey is still played on traditional grass fields at some local levels and lesser national divisions, it has been replaced by synthetic surfaces almost everywhere in the western world. There are three main types of artificial hockey surface:


title: Field hockey

text: Since the 1970s, sand-based pitches have been favoured as they dramatically speed up the game. However, in recent years there has been a massive increase in the number of "water-based" artificial turfs. Water-based synthetic turfs enable the ball to be transferred more quickly than on sand-based surfaces. It is this characteristic that has made them the surface of choice for international and national league competitions. Water-based surfaces are also less abrasive than sand-based surfaces and reduce the level of injury to players when they come into contact with the surface. The FIH are now proposing that new surfaces being laid should be of a hybrid variety which require less watering. This is due to the negative ecological effects of the high water requirements of water-based synthetic fields. It has also been stated that the decision to make artificial surfaces mandatory greatly favoured more affluent countries who could afford these new pitches.


title: Field hockey

text: The game is played between two teams of eleven, 10 field players and one goal keeper, are permitted to be on the pitch at any one time. The remaining players may be substituted in any combination. There is an unlimited number of times a team can sub in and out. Substitutions are permitted at any point in the game, apart from between the award and end of a penalty corner; two exceptions to this rule is for injury or suspension of the defending goalkeeper, which is not allowed when playing with a field keep, or a player can exit the field, but you must wait until after the penalty corner is complete. Play is not stopped for a substitution (except of a goalkeeper), the players leave and rejoin the match simultaneously at the half-way line.


title: Field hockey

text: Players are permitted to play the ball with the flat of the 'face side' and with the edges of the head and handle of the field hockey stick with the exception that, for reasons of safety, the ball may not be struck 'hard' with a forehand edge stroke, because of the difficulty of controlling the height and direction of the ball from that stroke.


title: Field hockey

text: The flat side is always on the "natural" side for a right-handed person swinging the stick at the ball from right to left. Left-handed sticks are rare, as International Hockey Federation rules forbid their use in a game. To make a strike at the ball with a left-to-right swing the player must present the flat of the 'face' of the stick to the ball by 'reversing' the stick head, i.e. by turning the handle through approximately 180° (while a reverse edge hit would turn the stick head through approximately 90° from the position of an upright forehand stroke with the 'face' of the stick head).


title: Field hockey

text: Edge hitting of the ball underwent a two-year "experimental period", twice the usual length of an "experimental trial" and is still a matter of some controversy within the game. Ric Charlesworth, the former Australian coach, has been a strong critic of the unrestricted use of the reverse edge hit. The 'hard' forehand edge hit was banned after similar concerns were expressed about the ability of players to direct the ball accurately, but the reverse edge hit does appear to be more predictable and controllable than its counterpart. This type of hit is now more commonly referred to as the "forehand sweep" where the ball is hit with the flat side or "natural" side of the stick and not the rounded edge.


title: Field hockey

text: Other rules include; no foot-to-ball contact, no use of hands, no obstructing other players, no high back swing, no hacking, and no third party. If a player is dribbling the ball and either loses control and kicks the ball or another player interferes that player is not permitted to gain control and continue dribbling. The rules do not allow the person who kicked the ball to gain advantage from the kick, so the ball will automatically be passed on to the opposing team. Conversely, if no advantage is gained from kicking the ball, play should continue. Players may not obstruct another's chance of hitting the ball in any way. No shoving/using your body/stick to prevent advancement in the other team. Penalty for this is the opposing team receives the ball and if the problem continues, the player can be carded. While a player is taking a free hit or starting a corner the back swing of their hit cannot be too high for this is considered dangerous. Finally there may not be three players touching the ball at one time. Two players from opposing teams can battle for the ball, however if another player interferes it is considered third party and the ball automatically goes to the team who only had one player involved in the third party.


title: Field hockey

text: A match ordinarily consists of two periods of 35 minutes and a halftime interval of 5 minutes. Other periods and interval may be agreed by


title: Field hockey

text: both teams except as specified in Regulations for particular competitions. Since 2014, some international games have four 15-minute quarters with 2 minutes break between each quarter and 15 minutes break between quarter two and three. At the 2018 Commonwealth Games, held on the Gold Coast in Brisbane, the hockey games for both men and women had four 15-minute quarters.


title: Field hockey

text: In December 2018, the FIH announced rule changes that would make 15-minute quarters universal from January 2019. England Hockey confirmed that while no changes would be made to the domestic game mid-season, the new rules would be implemented at the start of the 2019–20 season. However, in July 2019 England Hockey announced that 17.5-minute quarters would only be implemented in elite domestic club games.


title: Field hockey

text: The game begins with a pass back from the centre-forward usually to the centre-half back from the halfway line. The opposing team cannot try to tackle this play until the ball has been pushed back. The team consists of eleven players, usually aligned as follows: goalkeeper, right fullback, left fullback, three half-backs and five forwards who are right wing, right inner, centre forward, left inner and left wing. These positions can change and adapt throughout the course of the game depending on the attacking and defensive style of the opposition.


title: Field hockey

text: When hockey positions are discussed, notions of fluidity are very common. Each team can be fielded with a maximum of 11 players and will typically arrange themselves into forwards, midfielders, and defensive players (fullbacks) with players frequently moving between these lines with the flow of play. Each team may also play with:


title: Field hockey

text: As hockey has a very dynamic style of play, it is difficult to simplify positions to the static formations which are common in association football. Although positions will typically be categorised as either fullback, halfback, midfield/inner or striker, it is important for players to have an understanding of every position on the field. For example, it is not uncommon to see a halfback overlap and end up in either attacking position, with the midfield and strikers being responsible for re-adjusting to fill the space they left. Movement between lines like this is particularly common across all positions.


title: Field hockey

text: This fluid Australian culture of hockey has been responsible for developing an international trend towards players occupying spaces on the field, not having assigned positions. Although they may have particular spaces on the field which they are more comfortable and effective as players, they are responsible for occupying the space nearest them. This fluid approach to hockey and player movement has made it easy for teams to transition between formations such as: ""3 at the back"", ""5 midfields"", ""2 at the front"", and more.


title: Field hockey

text: When the ball is inside the circle, they are defending and they have their stick in their hand, goalkeepers wearing full protective equipment are permitted to use their stick, feet, kickers or leg guards to propel the ball and to use their stick, feet, kickers, leg guards or any other part of their body to stop the ball or deflect it in any direction including over the back line. Similarly, field players are permitted to use their stick. They are not allowed to use their feet and legs to propel the ball, stop the ball or deflect it in any direction including over the back line. However, neither goalkeepers, or players with goalkeeping privileges are permitted to conduct themselves in a manner which is dangerous to other players by taking advantage of the protective equipment they wear.


title: Field hockey

text: Neither goalkeepers or players with goalkeeping privileges may lie on the ball, however, they are permitted to use arms, hands and any other part of their body to push the ball away. Lying on the ball deliberately will result in a penalty stroke, whereas if an umpire deems a goalkeeper has lain on the ball accidentally (e.g. it gets stuck in their protective equipment), a penalty corner is awarded.


title: Field hockey

text: "* The action above is permitted only as part of a goal saving action or to move the ball away from the possibility of a goal scoring action by opponents. It does not permit a goalkeeper or player with goalkeeping privileges to propel the ball forcefully with arms, hands or body so that it travels a long distance"


title: Field hockey

text: When the ball is outside the circle they are defending, goalkeepers or players with goalkeeping privileges are only permitted to play the ball with their stick. Further, a goalkeeper, or player with goalkeeping privileges who is wearing a helmet, must not take part in the match outside the 23m area they are defending, except when taking a penalty stroke. A goalkeeper must wear protective headgear at all times, except when taking a penalty stroke.


title: Field hockey

text: For the purposes of the rules, all players on the team in possession of the ball are attackers, and those on the team without the ball are defenders, yet throughout the game being played you are always "defending" your goal and "attacking" the opposite goal.


title: Field hockey

text: The match is officiated by two field umpires. Traditionally each umpire generally controls half of the field, divided roughly diagonally. These umpires are often assisted by a technical bench including a timekeeper and record keeper.


title: Field hockey

text: Prior to the start of the game, a coin is tossed and the winning captain can choose a starting end or whether to start with the ball. Since 2017 the game consists of four periods of 15 minutes with a 2-minute break after every period, and a 15-minute intermission at half time before changing ends. At the start of each period, as well as after goals are scored, play is started with a pass from the centre of the field. All players must start in their defensive half (apart from the player making the pass), but the ball may be played in any direction along the floor. Each team starts with the ball in one half, and the team that conceded the goal has possession for the restart. Teams trade sides at halftime.


title: Field hockey

text: Field players may only play the ball with the face of the stick. If the back side of the stick is used, it is a penalty and the other team will get the ball back. Tackling is permitted as long as the tackler does not make contact with the attacker or the other person's stick before playing the ball (contact after the tackle may also be penalised if the tackle was made from a position where contact was inevitable). Further, the player with the ball may not deliberately use his body to push a defender out of the way.


title: Field hockey

text: Field players may not play the ball with their feet, but if the ball accidentally hits the feet, and the player gains no benefit from the contact, then the contact is not penalised. Although there has been a change in the wording of this rule from 1 January 2007, the current FIH umpires' briefing instructs umpires not to change the way they interpret this rule.


title: Field hockey

text: Obstruction typically occurs in three circumstances – when a defender comes between the player with possession and the ball in order to prevent them tackling; when a defender's stick comes between the attacker's stick and the ball or makes contact with the attacker's stick or body; and also when blocking the opposition's attempt to tackle a teammate with the ball (called "third party obstruction").


title: Field hockey

text: When the ball passes completely over the sidelines (on the sideline is still in), it is returned to play with a sideline hit, taken by a member of the team whose players were not the last to touch the ball before crossing the sideline. The ball must be placed on the sideline, with the hit taken from as near the place the ball went out of play as possible. If it crosses the back line after last touched by an attacker, a hit is awarded. A 15 m hit is also awarded for offences committed by the attacking side within 15 m of the end of the pitch they are attacking.


title: Field hockey

text: Set plays are often utilised for specific situations such as a penalty corner or free hit. For instance, many teams have penalty corner variations that they can use to beat the defensive team. The coach may have plays that sends the ball between two defenders and lets the player attack the opposing team's goal. There are no set plays unless your team has them.


title: Field hockey

text: Free hits are awarded when offences are committed outside the scoring circles (the term 'free hit' is standard usage but the ball need not be hit). The ball may be hit, pushed or lifted in any direction by the team offended against. The ball can be lifted from a free hit but not by hitting, you must flick or scoop to lift from a free hit. (In previous versions of the rules, hits in the area outside the circle in open play have been permitted but lifting one direction from a free hit was prohibited). Opponents must move from the ball when a free hit is awarded. A free hit must be taken from within playing distance of the place of the offence for which it was awarded and the ball must be stationary when the free hit is taken.


title: Field hockey

text: As mentioned above, a 15 m hit is awarded if an attacking player commits a foul forward of that line, or if the ball passes over the back line off an attacker. These free hits are taken in-line with where the foul was committed (taking a line parallel with the sideline between where the offence was committed, or the ball went out of play). When an attacking free hit is awarded within 5 m of the circle everyone including the person taking the penalty must be five meters from the circle and everyone apart from the person taking the free hit must be five meters away from the ball. When taking an attacking free hit, the ball may not be hit straight into the circle if you are within your attacking 23 meter area (25-yard area). It has to travel 5 meters before going in.


title: Field hockey

text: In February 2009 the FIH introduced, as a "Mandatory Experiment" for international competition, an updated version of the free-hit rule. The changes allows a player taking a free hit to pass the ball to themselves. Importantly, this is not a "play on" situation, but to the untrained eye it may appear to be. The player must play the ball any distance in two separate motions, before continuing as if it were a play-on situation. They may raise an aerial or overhead immediately as the second action, or any other stroke permitted by the rules of field hockey. At high-school level, this is called a self pass and was adopted in Pennsylvania in 2010 as a legal technique for putting the ball in play.


title: Field hockey

text: Also, all players (from both teams) must be at least 5 m from any free hit awarded to the attack within the 23 m area. The ball may not travel directly into the circle from a free hit to the attack within the 23 m area without first being touched by another player or being dribbled at least 5 m by a player making a "self-pass". These experimental rules apply to all free-hit situations, including sideline and corner hits. National associations may also choose to introduce these rules for their domestic competitions.


title: Field hockey

text: A free hit from the 23-metre line – called a long corner – is awarded to the attacking team if the ball goes over the back-line after last being touched by a defender, provided they do not play it over the back-line deliberately, in which case a penalty corner is awarded. This free hit is played by the attacking team from a spot on the 23-metre line, in line with where the ball went out of play. All the parameters of an attacking free hit within the attacking quarter of the playing surface apply.


title: Field hockey

text: Short corners begin with five defenders (usually including the keeper) positioned behind the back line and the ball placed at least 10 yards from the nearest goal post. All other players in the defending team must be beyond the centre line, that is not in their 'own' half of the pitch, until the ball is in play. Attacking players begin the play standing outside the scoring circle, except for one attacker who starts the corner by playing the ball from a mark 10 m either side of the goal (the circle has a 14.63 m radius). This player puts the ball into play by pushing or hitting the ball to the other attackers outside the circle; the ball must pass outside the circle and then put back into the circle before the attackers may make a shot at the goal from which a goal can be scored. FIH rules do not forbid a shot at goal before the ball leaves the circle after being 'inserted', nor is a shot at the goal from outside the circle prohibited, but a goal cannot be scored at all if the ball has not gone out of the circle and cannot be scored from a shot from outside the circle if it is not again played by an attacking player before it enters the goal.


title: Field hockey

text: For safety reasons, the first shot of a penalty corner must not exceed 460 mm high (the height of the "backboard" of the goal) at the point it crosses the goal line if it is hit. However, if the ball is deemed to be below backboard height, the ball can be subsequently deflected above this height by another player (defender or attacker), providing that this deflection does not lead to danger. Note that the "Slap" stroke (a sweeping motion towards the ball, where the stick is kept on or close to the ground when striking the ball) is classed as a hit, and so the first shot at goal must be below backboard height for this type of shot also.


title: Field hockey

text: If the first shot at goal in a short corner situation is a push, flick or scoop, in particular the "drag flick" (which has become popular at international and national league standards), the shot is permitted to rise above the height of the backboard, as long as the shot is not deemed dangerous to any opponent. This form of shooting was developed because it is not height restricted in the same way as the first hit shot at the goal and players with good technique are able to drag-flick with as much power as many others can hit a ball.


title: Field hockey

text: A penalty stroke is awarded when a defender commits a foul in the circle (accidental or otherwise) that prevents a probable goal or commits a deliberate foul in the circle or if defenders repeatedly run from the back line too early at a penalty corner. The penalty stroke is taken by a single attacker in the circle, against the goalkeeper, from a spot 6.4 m from goal. The ball is played only once at goal by the attacker using a push, flick or scoop stroke. If the shot is saved, play is restarted with a 15 m hit to the defenders. When a goal is scored, play is restarted in the normal way.


title: Field hockey

text: According to the Rules of Hockey 2015 issued by the FIH there are only two criteria for a dangerously played ball. The first is legitimate evasive action by an opponent (what constitutes legitimate evasive action is an umpiring judgment). The second is specific to the rule concerning a shot at goal at a penalty corner but is generally, if somewhat inconsistently, applied throughout the game and in all parts of the pitch: it is that a ball lifted above knee height and at an opponent who is within 5m of the ball is certainly dangerous.


title: Field hockey

text: The velocity of the ball is not mentioned in the rules concerning a dangerously played ball. A ball that hits a player above the knee may on some occasions not be penalised, this is at the umpire's discretion. A jab tackle, for example, might accidentally lift the ball above knee height into an opponent from close range but at such low velocity as not to be, in the opinion of the umpire, dangerous play. In the same way a high-velocity hit at very close range into an opponent, but below knee height, could be considered to be dangerous or reckless play in the view of the umpire, especially when safer alternatives are open to the striker of the ball.


title: Field hockey

text: A ball that has been lifted high so that it will fall among close opponents may be deemed to be potentially dangerous and play may be stopped for that reason. A lifted ball that is falling to a player in clear space may be made potentially dangerous by the actions of an opponent closing to within 5m of the receiver before the ball has been controlled to ground – a rule which is often only loosely applied; the distance allowed is often only what might be described as playing distance, 2–3 m, and opponents tend to be permitted to close on the ball as soon as the receiver plays it: these unofficial variations are often based on the umpire's perception of the skill of the players i.e. on the level of the game, in order to maintain game flow, which umpires are in general in both Rules and Briefing instructed to do, by not penalising when it is unnecessary to do so; this is also a matter at the umpire's discretion.


title: Field hockey

text: The term "falling ball" is important in what may be termed encroaching offences. It is generally only considered an offence to encroach on an opponent receiving a lifted ball that has been lifted to above head height (although the height is not specified in rule) and is falling. So, for example, a lifted shot at the goal which is still rising as it crosses the goal line (or would have been rising as it crossed the goal line) can be legitimately followed up by any of the attacking team looking for a rebound.


title: Field hockey

text: In general even potentially dangerous play is not penalised if an opponent is not disadvantaged by it or, obviously, not injured by it so that he cannot continue. A personal penalty, that is a caution or a suspension, rather than a team penalty, such as a free ball or a penalty corner, may be (many would say should be or even must be, but again this is at the umpire's discretion) issued to the guilty party after an advantage allowed by the umpire has been played out in any situation where an offence has occurred, including dangerous play (but once advantage has been allowed the umpire cannot then call play back and award a team penalty).


title: Field hockey

text: It is not an offence to lift the ball over an opponent's stick (or body on the ground), provided that it is done with consideration for the safety of the opponent and not dangerously. For example, a skilful attacker may lift the ball over a defenders stick or prone body and run past them, however if the attacker lifts the ball into or at the defender's body, this would almost certainly be regarded as dangerous.


title: Field hockey

text: It is not against the rules to bounce the ball on the stick and even to run with it while doing so, as long as that does not lead to a potentially dangerous conflict with an opponent who is attempting to make a tackle. For example, two players trying to play at the ball in the air at the same time, would probably be considered a dangerous situation and it is likely that the player who first put the ball up or who was so 'carrying' it would be penalised.


title: Field hockey

text: Dangerous play rules also apply to the usage of the stick when approaching the ball, making a stroke at it (replacing what was at one time referred to as the "sticks" rule, which once forbade the raising of any part of the stick above the shoulder during any play. This last restriction has been removed but the stick should still not be used in a way that endangers an opponent) or attempting to tackle, (fouls relating to tripping, impeding and obstruction). The use of the stick to strike an opponent will usually be much more severely dealt with by the umpires than offences such as barging, impeding and obstruction with the body, although these are also dealt with firmly, especially when these fouls are intentional: field hockey is a non-contact game.


title: Field hockey

text: If a coach is sent off, depending on local rules, a player may have to leave the field for the remaining length of the match.


title: Field hockey

text: In addition to their colours, field hockey penalty cards are often shaped differently, so they can be recognised easily. Green cards are normally triangular, yellow cards rectangular and red cards circular.


title: Field hockey

text: Unlike football, a player may receive more than one green or yellow card. However, they cannot receive the same card for the same offence (for example two yellows for dangerous play), and the second must always be a more serious card. In the case of a second yellow card for a different breach of the rules (for example a yellow for deliberate foot, and a second later in the game for dangerous play) the temporary suspension would be expected to be of considerably longer duration than the first. However, local playing conditions may mandate that cards are awarded only progressively, and not allow any second awards.


title: Field hockey

text: Umpires, if the free hit would have been in the attacking 23 m area, may upgrade the free hit to a penalty corner for dissent or other misconduct after the free hit has been awarded.


title: Field hockey

text: The teams' object is to play the ball into their attacking circle and, from there, hit, push or flick the ball into the goal, scoring a goal. The team with more goals after 60 minutes wins the game. The playing time may be shortened, particularly when younger players are involved, or for some tournament play. If the game is played in a countdown clock, like ice hockey, a goal can only count if the ball completely crosses the goal line and into the goal "before" time expires, not when the ball leaves the stick in the act of shooting.


title: Field hockey

text: If the score is tied at the end of the game, either a draw is declared or the game goes into extra time, or there is a penalty shoot-out, depending on the format of the competition. In many competitions (such as regular club competition, or in pool games in FIH international tournaments such as the Olympics or the World Cup), a tied result stands and the overall competition standings are adjusted accordingly. Since March 2013, when tie breaking is required, the official FIH Tournament Regulations mandate to no longer have extra time and go directly into a penalty shoot-out when a classification match ends in a tie. However, many associations follow the previous procedure consisting of two periods of 7.5 minutes of "golden goal" extra time during which the game ends as soon as one team scores.


title: Field hockey

text: There are many variations to overtime play that depend on the league or tournament rules. In American college play, a seven-a-side overtime period consists of a 10-minute golden goal period with seven players for each team. If the scores remain equal, the game enters a one-on-one competition where each team chooses five players to dribble from the line down to the circle against the opposing goalkeeper. The player has eight seconds to score against the goalkeeper while keeping the ball in bounds. The game ends after a goal is scored, the ball goes out of bounds, a foul is committed (ending in either a penalty stroke or flick or the end of the one-on-one) or time expires. If the tie still persists, more rounds are played until one team has scored.


title: Field hockey

text: The FIH implemented a two-year rules cycle with the 2007–08 edition of the rules, with the intention that the rules be reviewed on a biennial basis. The 2009 rulebook was officially released in early March 2009 (effective 1 May 2009), however the FIH published the major changes in February. The current rule book is effective from 1 January 2021.


title: Field hockey

text: There are sometimes minor variations in rules from competition to competition; for instance, the duration of matches is often varied for junior competitions or for carnivals. Different national associations also have slightly differing rules on player equipment.


title: Field hockey

text: The new Euro Hockey League and the Olympics has made major alterations to the rules to aid television viewers, such as splitting the game into four-quarters, and to try to improve player behavior, such as a two-minute suspension for green cards—the latter was also used in the 2010 World Cup and 2016 Olympics. In the United States, the NCAA has its own rules for inter-collegiate competitions; high school associations similarly play to different rules, usually using the rules published by the National Federation of State High School Associations (NFHS). This article assumes FIH rules unless otherwise stated. USA Field Hockey produces an annual summary of the differences.


title: Field hockey

text: In the United States, the games at the junior high level consist of four 12-minute periods, while the high-school level consists of two 30-minute periods. Many private American schools play 12-minute quarters, and some have adopted FIH rules rather than NFHS rules.


title: Field hockey

text: Players are required to wear mouth guards and shin guards in order to play the game. Also, there is a newer rule requiring certain types of sticks be used. In recent years, the NFHS rules have moved closer to FIH, but in 2011 a new rule requiring protective eyewear was introduced for the 2011 Fall season. Further clarification of NFHS's rule requiring protective eyewear states, "effective 1 January 2019, all eye protection shall be permanently labeled with the current ASTM 2713 standard for field hockey". Metal 'cage style' goggles favored by US high school lacrosse and permitted in high school field hockey is prohibited under FIH rules.


title: Field hockey

text: Each player carries a hockey stick that normally measures between 80 and 95 cm (31–38"); shorter or longer sticks are available. The length of the stick is based on the player's individual height: the top of the stick usually comes to the player's hip, and taller players typically have longer sticks. Goalkeepers can use either a specialised stick, or an ordinary field hockey stick. The specific goal-keeping sticks have another curve at the end of the stick, to give it more surface area to block the ball.


title: Field hockey

text: Sticks were traditionally made of wood, but are now often made also with fibreglass, kevlar or carbon fibre composites. Metal is forbidden from use in field hockey sticks, due to the risk of injury from sharp edges if the stick were to break. The stick has a rounded handle, has a J-shaped hook at the bottom, and is flattened on the left side (when looking down the handle with the hook facing upwards). All sticks must be right-handed; left-handed ones are prohibited.


title: Field hockey

text: There was traditionally a slight curve (called the bow, or rake) from the top to bottom of the face side of the stick and another on the 'heel' edge to the top of the handle (usually made according to the angle at which the handle part was inserted into the splice of the head part of the stick), which assisted in the positioning of the stick head in relation to the ball and made striking the ball easier and more accurate.


title: Field hockey

text: The hook at the bottom of the stick was only recently the tight curve (Indian style) that we have nowadays. The older 'English' sticks had a longer bend, making it very hard to use the stick on the reverse. For this reason players now use the tight curved sticks.


title: Field hockey

text: The handle makes up about the top third of the stick. It is wrapped in a grip similar to that used on tennis racket. The grip may be made of a variety of materials, including chamois leather, which improves grip in the wet and gives the stick a softer touch and different weighting it wrapped over a preexisting grip.


title: Field hockey

text: It was recently discovered that increasing the depth of the face bow made it easier to get high speeds from the dragflick and made the stroke easier to execute. At first, after this feature was introduced, the Hockey Rules Board placed a limit of 50 mm on the maximum depth of bow over the length of the stick but experience quickly demonstrated this to be excessive. New rules now limit this curve to under 25 mm so as to limit the power with which the ball can be flicked.


title: Field hockey

text: Standard field hockey balls are hard spherical balls, made of solid plastic (sometimes over a cork core), and are usually white, although they can be any colour as long as they contrast with the playing surface. The balls have a diameter of and a mass of . The ball is often covered with indentations to reduce aquaplaning that can cause an inconsistent ball speed on wet surfaces.


title: Field hockey

text: The 2007 rulebook saw major changes regarding goalkeepers. A fully equipped goalkeeper must wear a helmet, leg guards and kickers, and like all players, they must carry a stick. Goalkeepers may use either a field player's stick or a specialised goalkeeping stick provided always the stick is of legal dimensions. Usually field hockey goalkeepers also wear extensive additional protective equipment including chest guards, padded shorts, heavily padded hand protectors, groin protectors, neck protectors and arm guards. A goalie may not cross the 23 m line, the sole exception to this being if the goalkeeper is to take a penalty stroke at the other end of the field, when the clock is stopped. The goalkeeper can also remove their helmet for this action. While goalkeepers are allowed to use their feet and hands to clear the ball, like field players they may only use the one side of their stick. Slide tackling is permitted as long as it is with the intention of clearing the ball, not aimed at a player.


title: Field hockey

text: It is now also even possible for teams to have a full eleven outfield players and no goalkeeper at all. No player may wear a helmet or other goalkeeping equipment, neither will any player be able to play the ball with any other part of the body than with their stick. This may be used to offer a tactical advantage, for example, if a team is trailing with only a short time to play, or to allow for play to commence if no goalkeeper or kit is available.


title: Field hockey

text: The basic tactic in field hockey, as in association football and many other team games, is to outnumber the opponent in a particular area of the field at a moment in time. When in possession of the ball this temporary numerical superiority can be used to pass the ball around opponents so that they cannot effect a tackle because they cannot get within playing reach of the ball and to further use this numerical advantage to gain time and create clear space for making scoring shots on the opponent's goal. When not in possession of the ball numerical superiority is used to isolate and channel an opponent in possession and 'mark out' any passing options so that an interception or a tackle may be made to gain possession. Highly skillful players can sometimes get the better of more than one opponent and retain the ball and successfully pass or shoot but this tends to use more energy than quick early passing.


title: Field hockey

text: Every player has a role depending on their relationship to the ball if the team communicates throughout the play of the game. There will be players on the ball (offensively – ball carriers; defensively – pressure, support players, and movement players.


title: Field hockey

text: The main methods by which the ball is moved around the field by players are a) passing b) pushing the ball and running with it controlled to the front or right of the body and c) "dribbling"; where the player controls the ball with the stick and moves in various directions with it to elude opponents. To make a pass the ball may be propelled with a pushing stroke, where the player uses their wrists to push the stick head through the ball while the stick head is in contact with it; the "flick" or "scoop", similar to the push but with an additional arm and leg and rotational actions to lift the ball off the ground; and the "hit", where a swing at ball is taken and contact with it is often made very forcefully, causing the ball to be propelled at velocities in excess of . In order to produce a powerful hit, usually for travel over long distances or shooting at the goal, the stick is raised higher and swung with maximum power at the ball, a stroke sometimes known as a "drive".


title: Field hockey

text: Tackles are made by placing the stick into the path of the ball or playing the stick head or shaft directly at the ball. To increase the effectiveness of the tackle, players will often place the entire stick close to the ground horizontally, thus representing a wider barrier. To avoid the tackle, the ball carrier will either pass the ball to a teammate using any of the push, flick, or hit strokes, or attempt to maneuver or "drag" the ball around the tackle, trying to deceive the tackler.


title: Field hockey

text: In recent years, the penalty corner has gained importance as a goal scoring opportunity. Particularly with the technical development of the drag flick. Tactics at penalty corners to set up time for a shot with a drag flick or a hit shot at the goal involve various complex plays, including multiple passes before deflections towards the goal is made but the most common method of shooting is the direct flick or hit at the goal.


title: Field hockey

text: At the highest level, field hockey is a fast moving, highly skilled game, with players using fast moves with the stick, quick accurate passing, and hard hits, in attempts to keep possession and move the ball towards the goal. Tackling with physical contact and otherwise physically obstructing players is not permitted. Some of the tactics used resemble football (soccer), but with greater ball speed.


title: Field hockey

text: With the 2009 changes to the rules regarding free hits in the attacking 23 m area, the common tactic of hitting the ball hard into the circle was forbidden. Although at higher levels this was considered tactically risky and low-percentage at creating scoring opportunities, it was used with some effect to 'win' penalty corners by forcing the ball onto a defender's foot or to deflect high (and dangerously) off a defender's stick. The FIH felt it was a dangerous practice that could easily lead to raised deflections and injuries in the circle, which is often crowded at a free-hit situation, and outlawed it.


title: Field hockey

text: The biggest two field hockey tournaments are the Olympic Games tournament, and the Hockey World Cup, which is also held every four years. Apart from this, there is the Pro League held each year for the nine top-ranked teams. Field hockey has also been played at the Commonwealth Games since 1998.


title: Field hockey

text: Of the men's teams, Pakistan has won the Hockey World Cup four times, more times than any other side. India has won the Hockey at the Summer Olympics eight times, including in six successive Olympiads.


title: Field hockey

text: Of the female teams, the Netherlands has won the Hockey World cup the most times, with six titles. At the Olympics, Australia and the Netherlands have both won three Olympic tournaments.


title: Field hockey

text: India and Pakistan dominated men's hockey until the early 1980s, winning eight Olympic golds and three of the first five world cups, respectively, but have become less prominent with the ascendancy of Belgium, the Netherlands, Germany, New Zealand, Australia, and Spain since the late 1980s, as grass playing surfaces were replaced with artificial turf. Other notable men's nations include Argentina, England (who combine with other British "Home Nations" to form the Great Britain side at Olympic events) and South Korea.


title: Field hockey

text: Netherlands, Australia and Argentina are the most successful national teams among women. The Netherlands was the predominant women's team before field hockey was added to Olympic events. In the early 1990s, Australia emerged as the strongest women's country although retirement of a number of players weakened the team. Argentina improved its play on the 2000s, heading IFH rankings in 2003, 2010 and 2013. Other prominent women's teams are Germany, Great Britain, China, South Korea and India. Four nations have won Olympic gold medals in both men’s and women’s hockey: Germany, Netherlands, Australia and Great Britain.


title: Field hockey

text: For a couple of years, Belgium has emerged as a leading nation, with a World Champions title (2018), a European Champions title (2019), a silver medal at the Olympics (2016) and a lead on the FIH men's team world ranking.


title: Field hockey

text: This is a list of the major international field hockey tournaments, in chronological order. Tournaments included are:


title: Field hockey

text: Although invitational or not open to all countries, the following are also considered international tournaments:


title: Field hockey

text: A popular variant of field hockey is indoor field hockey, which is 6-a-side (5-a-side during 2014-2015) using a field which is reduced to approximately . Although many of the rules remain the same, including obstruction and feet, there are several key variations: players may not raise the ball unless shooting at goal, players may not hit the ball, instead using pushes to transfer it, and the sidelines are replaced with solid barriers, from which the ball will rebound and remain in play. In addition, the regulation guidelines for the indoor field hockey stick require a slightly thinner, lighter stick than an outdoor one.


title: Field hockey

text: As the name suggests, Hockey5s is a hockey variant which features five players on each team (including a goalkeeper). The field of play is 55 m long and 41.70 m wide—this is approximately half the size of a regular pitch. Few additional markings are needed as there is no penalty circle nor penalty corners; shots can be taken from anywhere on the pitch. Penalty strokes are replaced by a "challenge" which is like the one-on-one method used in a penalty shoot-out. The duration of the match is three 12-minute periods with an interval of two minutes between periods; golden goal periods are multiple 5-minute periods. The rules are simpler and it is intended that the game is faster, creating more shots on goal with less play in midfield, and more attractive to spectators.


title: Field hockey

text: An Asian qualification tournament for two places at the 2014 Youth Olympic Games was the first time an FIH event used the Hockey5s format. Hockey5s was also used for the Youth Olympic hockey tournament, the Pacific Games in 2015 and at the African Youth Games is 2018.


title: Field hockey

text: In 2022, the FIH staged its first senior international Hockey5s event, with a men's and women's event being held in Lausanne.


title: Field hockey

text: NOTE: Many of the sources here are suspect and may be unreliable. indicates a reference has been reviewed and is approved. All ticks will be removed when the article reconstruction is complete.


title: The Four Seasons (Vivaldi)

text: The Four Seasons () is a group of four violin concertos by Italian composer Antonio Vivaldi, each of which gives musical expression to a season of the year. These were composed around 1718−1720, when Vivaldi was the court chapel master in Mantua. They were published in 1725 in Amsterdam, together with eight additional concerti, as ("The Contest Between Harmony and Invention").


title: The Four Seasons (Vivaldi)

text: "The Four Seasons" is the best known of Vivaldi's works. Though three of the concerti are wholly original, the first, "Spring", borrows patterns from a sinfonia in the first act of Vivaldi's contemporaneous opera "Il Giustino". The inspiration for the concertos is not the countryside around Mantua, as initially supposed, where Vivaldi was living at the time, since according to Karl Heller they could have been written as early as 1716–1717, while Vivaldi was engaged with the court of Mantua only in 1718.


title: The Four Seasons (Vivaldi)

text: They were a revolution in musical conception: in them Vivaldi represented flowing creeks, singing birds (of different species, each specifically characterized), a shepherd and his barking dog, buzzing flies, storms, drunken dancers, hunting parties from both the hunters' and the prey's point of view, frozen landscapes, and warm winter fires.


title: The Four Seasons (Vivaldi)

text: Unusually for the period, Vivaldi published the concerti with (possibly written by the composer himself) that elucidated what it was in the spirit of each season that his music was intended to evoke. The concerti therefore stand as one of the earliest and most detailed examples of what would come to be called program music—in other words, music with a narrative element. Vivaldi took great pains to relate his music to the texts of the poems, translating the poetic lines themselves directly into the music on the page. For example, in the middle section of "Spring", when the goatherd sleeps, his barking dog can be heard in the viola section. The music is elsewhere similarly evocative of other natural sounds. Vivaldi divided each concerto into three movements (fast–slow–fast), and, likewise, each linked sonnet into three sections.


title: The Four Seasons (Vivaldi)

text: A performance of all four concerti may take about 40–43 minutes. Approximate timings of the individual concerti:


title: The Four Seasons (Vivaldi)

text: There is some debate as to whether the four concertos were written to accompany four sonnets or vice versa. Though it is not known who wrote the accompanying sonnets, the theory that Vivaldi wrote them is supported by the fact that each sonnet is broken into three sections, each neatly corresponding to a movement in the concerto. Regardless of the sonnets' authorship, "The Four Seasons" can be classified as program music, instrumental music intended to evoke something extra-musical, and an art form which Vivaldi was determined to prove sophisticated enough to be taken seriously.


title: The Four Seasons (Vivaldi)

text: In addition to these sonnets, Vivaldi provided instructions such as "The barking dog" (in the second movement of "Spring"), "Languor caused by the heat" (in the first movement of "Summer"), and "the drunkards have fallen asleep" (in the second movement of "Autumn").


title: The Four Seasons (Vivaldi)

text: The date and personnel on the first recording of "The Four Seasons" are disputed. There is a compact disc of a recording made by the violinist Alfredo Campoli taken from acetates of a French radio broadcast; these are thought to date from early in 1939. The first proper electrical recording was made in 1942 by Bernardino Molinari; though his is a somewhat different interpretation from modern performances, it is clearly recognisable as "The Four Seasons". Molinari's recording was made for Cetra, and was issued in Italy and subsequently in the United States on six double-sided 78s, in the 1940s. It was then reissued on long-playing album in 1950, and, later, on compact disc.


title: The Four Seasons (Vivaldi)

text: The first American recording was made in the final week of 1947 by the violinist Louis Kaufman. The recording was made at Carnegie Hall in advance of a scheduled recording ban effective 1 January 1948. The performers were The Concert Hall Chamber Orchestra under Henry Swoboda, Edith Weiss-Mann (harpsichord) and Edouard Nies-Berger (organ). This recording helped the re-popularisation of Vivaldi's music in the mainstream repertoire of Europe and America following on the work done by Molinari and others in Italy. It won the French Grand Prix du Disque in 1950, was elected to the Grammy Hall of Fame in 2002, and was selected the following year for the National Recording Registry in the Library of Congress. Kaufman, intrigued to learn that the four concertos were in fact part of a set of twelve, set about finding a full score and eventually recorded the other eight concertos in Zürich in 1950, making his the first recording of Vivaldi's complete Op. 8.


title: The Four Seasons (Vivaldi)

text: The ensemble I Musici recorded "The Four Seasons" several times, the debut recording in 1955 with Felix Ayo; a 1959 recording featuring Ayo again; and subsequent recordings featuring Roberto Michelucci (1969), Pina Carmirelli (1982), Federico Agostini (1990), and Mariana Sîrbu (1995). There is also a video recording of "The Four Seasons" performed by I Musici in Antonio Vivaldi's hometown of Venice, filmed by Anton van Munster in 1988. The 1969 Argo recording by the Academy of St. Martin-in-the-Fields conducted by Neville Marriner and featuring the soloist Alan Loveday sold over half a million copies; it became the ensemble's first gold record.


title: The Four Seasons (Vivaldi)

text: I Solisti di Zagreb, under the baton of Antonio Janigro with Jan Tomasow as violin soloist and Anton Heiller on harpsichord, followed in 1957 on the Vanguard label, further reissued under the Philips and other labels. Wilfrid Mellers, an English music critic, musicologist and composer wrote of this performance, "the soloists phrase their lyricism beautifully." John Thornton wrote about this recording, "Here is matchless ensemble playing, topped by Tomasow's secure playing. Janigro reveals his talent for conducting, which competes with his considerable talent for cello playing."


title: The Four Seasons (Vivaldi)

text: Nigel Kennedy's 1989 recording of "The Four Seasons" with the English Chamber Orchestra sold over copies, becoming one of the best-selling classical works ever. Gil Shaham and the Orpheus Chamber Orchestra recorded "The Four Seasons" as well as a music video for the first movement of "Winter" that was featured regularly on The Weather Channel in the mid-1990s.


title: The Four Seasons (Vivaldi)

text: Surround sound versions of the piece have been issued on Super Audio CD by Richard Tognetti, Pinchas Zukerman, Jonathan Carney and Rachel Podger.


title: The Four Seasons (Vivaldi)

text: "The World's Encyclopedia of Recorded Music" in 1952 cites only two recordings of "The Four Seasons" – by Molinari and Kaufman. , approximately 1,000 recorded versions have been made since Campoli's in 1939.


title: The Four Seasons (Vivaldi)

text: Classical musicians have sought to distinguish their recordings of "The Four Seasons", with historically informed performances, and embellishments, to the point of varying the instruments and tempi, or playing notes differently from the listener's expectation (whether specified by the composer or not). It is said that Vivaldi's work presents such opportunities for improvisation.


title: The Four Seasons (Vivaldi)

text: The Four Seasons was voted #67 in the Classic FM Hall of Fame. Three of the four concerti were included in the Classic 100 Concerto listing.


title: The Four Seasons (Vivaldi)

text: Derivative works of these concerti include arrangements, transcriptions, covers, remixes, samples, and parodies in music — themes in theater and opera, soundtracks in films (or video games), and choreography in ballet (along with contemporary dance, figure skating, rhythmic gymnastics, synchronized swimming, etc.) — either in their entirety, single movements, or medleys. Antonio Vivaldi appears to have started this trend of adapting music from "The Four Seasons", and since then it has expanded into many aspects of the performing arts (as have other instrumental & vocal works by the composer). This "contest between harmony and invention" (as it were) now involves various genres around the world:


title: Knot (unit)

text: The knot () is a unit of speed equal to one nautical mile per hour, exactly (approximately or ). The ISO standard symbol for the knot is kn. The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO). The knot is a non-SI unit. The knot is used in meteorology, and in maritime and air navigation. A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour.


title: Knot (unit)

text: The length of the internationally agreed nautical mile is . The US adopted the international definition in 1954, having previously used the US nautical mile (). The UK adopted the international nautical mile definition in 1970, having previously used the UK Admiralty nautical mile ( or ).


title: Knot (unit)

text: The speeds of vessels relative to the fluids in which they travel (boat speeds and air speeds) are measured in knots. For consistency, the speeds of navigational fluids (tidal streams, river currents and wind speeds) are also measured in knots. Thus, speed over the ground (SOG; ground speed (GS) in aircraft) and rate of progress towards a distant point ("velocity made good", VMG) are also given in knots.


title: Knot (unit)

text: Until the mid-19th century, vessel speed at sea was measured using a chip log. This consisted of a wooden panel, attached by line to a reel, and weighted on one edge to float perpendicularly to the water surface and thus present substantial resistance to the water moving around it. The chip log was cast over the stern of the moving vessel and the line allowed to pay out. Knots tied at a distance of 47 feet 3 inches (14.4018 m) from each other, passed through a sailor's fingers, while another sailor used a 30-second sand-glass (28-second sand-glass is the currently accepted timing) to time the operation. The knot count would be reported and used in the sailing master's dead reckoning and navigation. This method gives a value for the knot of 20.25 in/s, or 1.85166 km/h. The difference from the modern definition is less than 0.02%.


title: Knot (unit)

text: Although the unit "knot" does not fit within the SI system, its retention for nautical and aviation use is important because the length of a nautical mile, upon which the knot is based, is closely related to the longitude/latitude geographic coordinate system. As a result, nautical miles and knots are convenient units to use when navigating an aircraft or ship.


title: Knot (unit)

text: On a standard nautical chart using Mercator projection, the horizontal (East–West) scale varies with latitude. On a chart of the North Atlantic, the scale varies by a factor of two from Florida to Greenland. A single graphic scale, of the sort on many maps, would therefore be useless on such a chart. Since the length of a nautical mile, for practical purposes, is equivalent to about a minute of latitude, a distance in nautical miles on a chart can easily be measured by using dividers and the latitude scales on the sides of the chart. Recent British Admiralty charts have a latitude scale down the middle to make this even easier.


title: Knot (unit)

text: Speed is sometimes incorrectly expressed as "knots per hour", which would mean "nautical miles per hour per hour" and thus would refer to acceleration.


title: Knot (unit)

text: Prior to 1969, airworthiness standards for civil aircraft in the United States Federal Aviation Regulations specified that distances were to be in statute miles, and speeds in miles per hour. In 1969, these standards were progressively amended to specify that distances were to be in nautical miles, and speeds in knots.


title: Knot (unit)

text: The indicated airspeed is close to the true airspeed only at sea level in standard conditions and at low speeds. At , an indicated airspeed of 300 kn may correspond to a true airspeed of 500 kn in standard conditions.