title: Vacuum content: and cold cathode. In the hot cathode version an electrically heated filament produces an electron beam. The electrons travel through the gauge and ionize gas molecules around them. The resulting ions are collected at a negative electrode. The current depends on the number of ions, which depends on the pressure in the gauge. Hot cathode gauges are accurate from 10 torr to 10 torr. The principle behind cold cathode version is the same, except that electrons are produced in a discharge created by a high voltage electrical discharge. Cold cathode gauges are accurate from 10 torr to 10 torr. Ionization


title: Vacuum content: gauge calibration is very sensitive to construction geometry, chemical composition of gases being measured, corrosion and surface deposits. Their calibration can be invalidated by activation at atmospheric pressure or low vacuum. The composition of gases at high vacuums will usually be unpredictable, so a mass spectrometer must be used in conjunction with the ionization gauge for accurate measurement. Vacuum is useful in a variety of processes and devices. Its first widespread use was in the incandescent light bulb to protect the filament from chemical degradation. The chemical inertness produced by a vacuum is also useful for electron beam welding, cold


title: Vacuum content: welding, vacuum packing and vacuum frying. Ultra-high vacuum is used in the study of atomically clean substrates, as only a very good vacuum preserves atomic-scale clean surfaces for a reasonably long time (on the order of minutes to days). High to ultra-high vacuum removes the obstruction of air, allowing particle beams to deposit or remove materials without contamination. This is the principle behind chemical vapor deposition, physical vapor deposition, and dry etching which are essential to the fabrication of semiconductors and optical coatings, and to surface science. The reduction of convection provides the thermal insulation of thermos bottles. Deep vacuum


title: Vacuum content: lowers the boiling point of liquids and promotes low temperature outgassing which is used in freeze drying, adhesive preparation, distillation, metallurgy, and process purging. The electrical properties of vacuum make electron microscopes and vacuum tubes possible, including cathode ray tubes. Vacuum interrupters are used in electrical switchgear. Vacuum arc processes are industrially important for production of certain grades of steel or high purity materials. The elimination of air friction is useful for flywheel energy storage and ultracentrifuges. Vacuums are commonly used to produce suction, which has an even wider variety of applications. The Newcomen steam engine used vacuum instead of


title: Vacuum content: pressure to drive a piston. In the 19th century, vacuum was used for traction on Isambard Kingdom Brunel's experimental atmospheric railway. Vacuum brakes were once widely used on trains in the UK but, except on heritage railways, they have been replaced by air brakes. Manifold vacuum can be used to drive accessories on automobiles. The best-known application is the vacuum servo, used to provide power assistance for the brakes. Obsolete applications include vacuum-driven windscreen wipers and Autovac fuel pumps. Some aircraft instruments (Attitude Indicator (AI) and the Heading Indicator (HI)) are typically vacuum-powered, as protection against loss of all (electrically


title: Vacuum content: powered) instruments, since early aircraft often did not have electrical systems, and since there are two readily available sources of vacuum on a moving aircraft, the engine and an external venturi. Vacuum induction melting uses electromagnetic induction within a vacuum. Maintaining a vacuum in the Condenser is an important aspect of the efficient operation of steam turbines. A steam jet ejector or liquid ring vacuum pump is used for this purpose. The typical vacuum maintained in the Condenser steam space at the exhaust of the turbine (also called Condenser Backpressure) is in the range 5 to 15 kPa (absolute), depending


title: Vacuum content: on the type of condenser and the ambient conditions. Evaporation and sublimation into a vacuum is called outgassing. All materials, solid or liquid, have a small vapour pressure, and their outgassing becomes important when the vacuum pressure falls below this vapour pressure. Outgassing has the same effect as a leak and can limit the achievable vacuum. Outgassing products may condense on nearby colder surfaces, which can be troublesome if they obscure optical instruments or react with other materials. This is of great concern to space missions, where an obscured telescope or solar cell can ruin an expensive mission. The most


title: Vacuum content: prevalent outgassing product in vacuum systems is water absorbed by chamber materials. It can be reduced by desiccating or baking the chamber, and removing absorbent materials. Outgassed water can condense in the oil of rotary vane pumps and reduce their net speed drastically if gas ballasting is not used. High vacuum systems must be clean and free of organic matter to minimize outgassing. Ultra-high vacuum systems are usually baked, preferably under vacuum, to temporarily raise the vapour pressure of all outgassing materials and boil them off. Once the bulk of the outgassing materials are boiled off and evacuated, the system


title: Vacuum content: may be cooled to lower vapour pressures and minimize residual outgassing during actual operation. Some systems are cooled well below room temperature by liquid nitrogen to shut down residual outgassing and simultaneously cryopump the system. Fluids cannot generally be pulled, so a vacuum cannot be created by suction. Suction can spread and dilute a vacuum by letting a higher pressure push fluids into it, but the vacuum has to be created first before suction can occur. The easiest way to create an artificial vacuum is to expand the volume of a container. For example, the diaphragm muscle expands the chest


title: Vacuum content: cavity, which causes the volume of the lungs to increase. This expansion reduces the pressure and creates a partial vacuum, which is soon filled by air pushed in by atmospheric pressure. To continue evacuating a chamber indefinitely without requiring infinite growth, a compartment of the vacuum can be repeatedly closed off, exhausted, and expanded again. This is the principle behind positive displacement pumps, like the manual water pump for example. Inside the pump, a mechanism expands a small sealed cavity to create a vacuum. Because of the pressure differential, some fluid from the chamber (or the well, in our example)


title: Vacuum content: is pushed into the pump's small cavity. The pump's cavity is then sealed from the chamber, opened to the atmosphere, and squeezed back to a minute size. The above explanation is merely a simple introduction to vacuum pumping, and is not representative of the entire range of pumps in use. Many variations of the positive displacement pump have been developed, and many other pump designs rely on fundamentally different principles. Momentum transfer pumps, which bear some similarities to dynamic pumps used at higher pressures, can achieve much higher quality vacuums than positive displacement pumps. Entrapment pumps can capture gases in


title: Vacuum content: a solid or absorbed state, often with no moving parts, no seals and no vibration. None of these pumps are universal; each type has important performance limitations. They all share a difficulty in pumping low molecular weight gases, especially hydrogen, helium, and neon. The lowest pressure that can be attained in a system is also dependent on many things other than the nature of the pumps. Multiple pumps may be connected in series, called stages, to achieve higher vacuums. The choice of seals, chamber geometry, materials, and pump-down procedures will all have an impact. Collectively, these are called "vacuum technique".


title: Vacuum content: And sometimes, the final pressure is not the only relevant characteristic. Pumping systems differ in oil contamination, vibration, preferential pumping of certain gases, pump-down speeds, intermittent duty cycle, reliability, or tolerance to high leakage rates. In ultra high vacuum systems, some very "odd" leakage paths and outgassing sources must be considered. The water absorption of aluminium and palladium becomes an unacceptable source of outgassing, and even the adsorptivity of hard metals such as stainless steel or titanium must be considered. Some oils and greases will boil off in extreme vacuums. The permeability of the metallic chamber walls may have to


title: Vacuum content: be considered, and the grain direction of the metallic flanges should be parallel to the flange face. The lowest pressures currently achievable in laboratory are about 10 torr (13 pPa). However, pressures as low as (6.7 fPa) have been indirectly measured in a 4 K cryogenic vacuum system. This corresponds to ≈100 particles/cm. Humans and animals exposed to vacuum will lose consciousness after a few seconds and die of hypoxia within minutes, but the symptoms are not nearly as graphic as commonly depicted in media and popular culture. The reduction in pressure lowers the temperature at which blood and other


title: Vacuum content: body fluids boil, but the elastic pressure of blood vessels ensures that this boiling point remains above the internal body temperature of Although the blood will not boil, the formation of gas bubbles in bodily fluids at reduced pressures, known as ebullism, is still a concern. The gas may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. Swelling and ebullism can be restrained by containment in a flight suit. Shuttle astronauts wore a fitted elastic garment called the Crew Altitude Protection Suit (CAPS) which prevents ebullism at


title: Vacuum content: pressures as low as 2 kPa (15 Torr). Rapid boiling will cool the skin and create frost, particularly in the mouth, but this is not a significant hazard. Animal experiments show that rapid and complete recovery is normal for exposures shorter than 90 seconds, while longer full-body exposures are fatal and resuscitation has never been successful. A study by NASA on eight chimpanzees found all of them survived two and a half minute exposures to vacuum. There is only a limited amount of data available from human accidents, but it is consistent with animal data. Limbs may be exposed for


title: Vacuum content: much longer if breathing is not impaired. Robert Boyle was the first to show in 1660 that vacuum is lethal to small animals. An experiment indicates that plants are able to survive in a low pressure environment (1.5 kPa) for about 30 minutes. Cold or oxygen-rich atmospheres can sustain life at pressures much lower than atmospheric, as long as the density of oxygen is similar to that of standard sea-level atmosphere. The colder air temperatures found at altitudes of up to 3 km generally compensate for the lower pressures there. Above this altitude, oxygen enrichment is necessary to prevent altitude


title: Vacuum content: sickness in humans that did not undergo prior acclimatization, and spacesuits are necessary to prevent ebullism above 19 km. Most spacesuits use only 20 kPa (150 Torr) of pure oxygen. This pressure is high enough to prevent ebullism, but decompression sickness and gas embolisms can still occur if decompression rates are not managed. Rapid decompression can be much more dangerous than vacuum exposure itself. Even if the victim does not hold his or her breath, venting through the windpipe may be too slow to prevent the fatal rupture of the delicate alveoli of the lungs. Eardrums and sinuses may be


title: Vacuum content: ruptured by rapid decompression, soft tissues may bruise and seep blood, and the stress of shock will accelerate oxygen consumption leading to hypoxia. Injuries caused by rapid decompression are called barotrauma. A pressure drop of 13 kPa (100 Torr), which produces no symptoms if it is gradual, may be fatal if it occurs suddenly. Some extremophile microorganisms, such as tardigrades, can survive vacuum conditions for periods of days or weeks. Vacuum Vacuum is space devoid of matter. The word stems from the Latin adjective "vacuus" for "vacant" or "void". An approximation to such vacuum is a region with a gaseous


title: "Viking Age" content: kingdom of Fortriu. They defeated Eogán mac Óengusa, king of the Picts, his brother Bran, and the king of the Scots of Dál Riata, Áed mac Boanta, along with many members of the Pictish aristocracy in battle. The sophisticated kingdom that had been built fell apart, as did the Pictish leadership, which had been stable for more than 100 years since the time of Óengus mac Fergusa (The accession of Cináed mac Ailpín as king of both Picts and Scots can be attributed to the aftermath of this event). By the mid-9th century, the Norsemen had settled in Shetland, Orkney


title: Volleyball content: Volleyball Volleyball is a team sport in which two teams of six players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules. It has been a part of the official program of the Summer Olympic Games since 1964. The complete rules are extensive, but simply, play proceeds as follows: a player on one of the teams begins a 'rally' by serving the ball (tossing or releasing it and then hitting it with a hand or arm), from behind the back boundary line of the court, over


title: Volleyball content: the net, and into the receiving team's court. The receiving team must not let the ball be grounded within their court. The team may touch the ball up to 3 times, but individual players may not touch the ball twice consecutively. Typically, the first two touches are used to set up for an attack, an attempt to direct the ball back over the net in such a way that the serving team is unable to prevent it from being grounded in their court. The rally continues, with each team allowed as many as three consecutive touches, until either (1): a


title: Volleyball content: team makes a "kill", grounding the ball on the opponent's court and winning the rally; or (2): a team commits a "fault" and loses the rally. The team that wins the rally is awarded a point and serves the ball to start the next rally. A few of the most common faults include: The ball is usually played with the hands or arms, but players can legally strike or push (short contact) the ball with any part of the body. A number of consistent techniques have evolved in volleyball, including "spiking" and "blocking" (because these plays are made above the


title: Volleyball content: top of the net, the vertical jump is an athletic skill emphasized in the sport) as well as "passing", "setting", and specialized player positions and offensive and defensive structures. In the winter of 1895, in Holyoke, Massachusetts (United States), William G. Morgan, a YMCA physical education director, created a new game called "Mintonette", a name derived from the game of badminton, as a pastime to be played (preferably) indoors and by any number of players. The game took some of its characteristics from other sports such as tennis and handball. Another indoor sport, basketball, was catching on in the area,


title: Volleyball content: having been invented just ten miles (sixteen kilometers) away in the city of Springfield, Massachusetts, only four years before. Mintonette was designed to be an indoor sport, less rough than basketball, for older members of the YMCA, while still requiring a bit of athletic effort. The first rules, written down by William G Morgan, called for a net high, a court, and any number of players. A match was composed of nine innings with three serves for each team in each inning, and no limit to the number of ball contacts for each team before sending the ball to the


title: Volleyball content: opponents' court. In case of a serving error, a second try was allowed. Hitting the ball into the net was considered a foul (with loss of the point or a side-out)—except in the case of the first-try serve. After an observer, Alfred Halstead, noticed the volleying nature of the game at its first exhibition match in 1896, played at the International YMCA Training School (now called Springfield College), the game quickly became known as "volleyball" (it was originally spelled as two words: ""volley ball""). Volleyball rules were slightly modified by the International YMCA Training School and the game spread around


title: Volleyball content: the country to various YMCAs. The first official ball used in volleyball is disputed; some sources say Spalding created the first official ball in 1896, while others claim it was created in 1900. The rules evolved over time: in 1916, in the Philippines, the skill and power of the set and spike had been introduced, and four years later a "three hits" rule and a rule against hitting from the back row were established. In 1917, the game was changed from requiring 21 points to win to a smaller 15 points to win. In 1919, about 16,000 volleyballs were distributed


title: Volleyball content: by the American Expeditionary Forces to their troops and allies, which sparked the growth of volleyball in new countries. The first country outside the United States to adopt volleyball was Canada in 1900. An international federation, the Fédération Internationale de Volleyball (FIVB), was founded in 1947, and the first World Championships were held in 1949 for men and 1952 for women. The sport is now popular in Brazil, in Europe (where especially Italy, the Netherlands, and countries from Eastern Europe have been major forces since the late 1980s), in Russia, and in other countries including China and the rest of


title: Volleyball content: Asia, as well as in the United States. Beach volleyball, a variation of the game played on sand and with only two players per team, became a FIVB-endorsed variation in 1987 and was added to the Olympic program at the 1996 Summer Olympics. Volleyball is also a sport at the Paralympics managed by the World Organization Volleyball for Disabled. Nudists were early adopters of the game with regular organized play in clubs as early as the late 1920s. By the 1960s, a volleyball court had become standard in almost all nudist/naturist clubs. Volleyball has been part of the Summer Olympics


title: Volleyball content: program for both men and women consistently since 1964. A volleyball court is , divided into equal square halves by a net with a width of . The top of the net is above the center of the court for men's competition, and for women's competition, varied for veterans and junior competitions. The minimum height clearance for indoor volleyball courts is , although a clearance of is recommended. A line from and parallel to the net is considered the "attack line". This "3 meter" (or "10-foot") line divides the court into "back row" and "front row" areas (also back court


title: Volleyball content: and front court). These are in turn divided into 3 areas each: these are numbered as follows, starting from area "1", which is the position of the serving player: After a team gains the serve (also known as siding out), its members must rotate in a clockwise direction, with the player previously in area "2" moving to area "1" and so on, with the player from area "1" moving to area "6". Each player rotates only one time after the team gains possession of the serve; the next time each player rotates will be after the other team wins possession


title: Volleyball content: of the ball and loses the point. The team courts are surrounded by an area called the free zone which is a minimum of 3 meters wide and which the players may enter and play within after the service of the ball. All lines denoting the boundaries of the team court and the attack zone are drawn or painted within the dimensions of the area and are therefore a part of the court or zone. If a ball comes in contact with the line, the ball is considered to be "in". An antenna is placed on each side of the


title: Volleyball content: net perpendicular to the sideline and is a vertical extension of the side boundary of the court. A ball passing over the net must pass completely between the antennae (or their theoretical extensions to the ceiling) without contacting them. FIVB regulations state that the ball must be spherical, made of leather or synthetic leather, have a circumference of 65–67 cm, a weight of 260–280 g and an inside pressure of 0.30–0.325 kg/cm. Other governing bodies have similar regulations. Each team consists of six players. To get play started, a team is chosen to serve by coin toss. A player from


title: Volleyball content: the serving team throws the ball into the air and attempts to hit the ball so it passes over the net on a course such that it will land in the opposing team's court (the "serve"). The opposing team must use a combination of no more than three contacts with the volleyball to return the ball to the opponent's side of the net. These contacts usually consist first of the "bump" or "pass" so that the ball's trajectory is aimed towards the player designated as the "setter"; second of the "set" (usually an over-hand pass using wrists to push finger-tips


title: Volleyball content: at the ball) by the setter so that the ball's trajectory is aimed towards a spot where one of the players designated as an "attacker" can hit it, and third by the "attacker" who "spikes" (jumping, raising one arm above the head and hitting the ball so it will move quickly down to the ground on the opponent's court) to return the ball over the net. The team with possession of the ball that is trying to attack the ball as described is said to be on "offense". The team on "defense" attempts to prevent the attacker from directing the


title: Volleyball content: ball into their court: players at the net jump and reach above the top (and if possible, across the plane) of the net to "block" the attacked ball. If the ball is hit around, above, or through the block, the defensive players arranged in the rest of the court attempt to control the ball with a "dig" (usually a fore-arm pass of a hard-driven ball). After a successful dig, the team transitions to offense. The game continues in this manner, rallying back and forth, until the ball touches the court within the boundaries or until an error is made. The


title: Volleyball content: most frequent errors that are made are either to fail to return the ball over the net within the allowed three touches, or to cause the ball to land outside the court. A ball is "in" if any part of it touches a sideline or end-line, and a strong spike may compress the ball enough when it lands that a ball which at first appears to be going out may actually be in. Players may travel well outside the court to play a ball that has gone over a sideline or end-line in the air. Other common errors include a


title: Volleyball content: player touching the ball twice in succession, a player "catching" the ball, a player touching the net while attempting to play the ball, or a player penetrating under the net into the opponent's court. There are a large number of other errors specified in the rules, although most of them are infrequent occurrences. These errors include back-row or libero players spiking the ball or blocking (back-row players may spike the ball if they jump from behind the attack line), players not being in the correct position when the ball is served, attacking the serve in the front court and above


title: Volleyball content: the height of the net, using another player as a source of support to reach the ball, stepping over the back boundary line when serving, taking more than 8 seconds to serve, or playing the ball when it is above the opponent's court. When the ball contacts the floor within the court boundaries or an error is made, the team that did not make the error is awarded a point, whether they served the ball or not. If the ball hits the line, the ball is counted as in. The team that won the point serves for the next point.


title: Volleyball content: If the team that won the point served in the previous point, the same player serves again. If the team that won the point did not serve the previous point, the players of the serving team rotate their position on the court in a clockwise manner. The game continues, with the first team to score 25 points by a two-point margin awarded the set. Matches are best-of-five sets and the fifth set, if necessary, is usually played to 15 points. (Scoring differs between leagues, tournaments, and levels; high schools sometimes play best-of-three to 25; in the NCAA matches are played


title: Volleyball content: best-of-five to 25 as of the 2008 season.) Before 1999, points could be scored only when a team had the serve ("side-out scoring") and all sets went up to only 15 points. The FIVB changed the rules in 1999 (with the changes being compulsory in 2000) to use the current scoring system (formerly known as "rally point system"), primarily to make the length of the match more predictable and to make the game more spectator- and television-friendly. The final year of side-out scoring at the NCAA Division I Women's Volleyball Championship was 2000. Rally point scoring debuted in 2001, and


title: Volleyball content: games were played to 30 points through 2007. For the 2008 season, games were renamed "sets" and reduced to 25 points to win. Most high schools in the U.S. changed to rally scoring in 2003, and several states implemented it the previous year on an experimental basis. The libero player was introduced internationally in 1998, and made its debut for NCAA competition in 2002. The libero is a player specialized in defensive skills: the libero must wear a contrasting jersey color from his or her teammates and cannot block or attack the ball when it is entirely above net height.


title: Volleyball content: When the ball is not in play, the libero can replace any back-row player, without prior notice to the officials. This replacement does not count against the substitution limit each team is allowed per set, although the libero may be replaced only by the player whom he or she replaced. Most U.S. high schools added the libero position from 2003 to 2005. Nowadays, libero works as a second setter, when setter dig the ball, libero will help to set. The libero may function as a setter only under certain restrictions. If she/he makes an overhand set, she/he must be standing


title: Volleyball content: behind (and not stepping on) the 3-meter line; otherwise, the ball cannot be attacked above the net in front of the 3-meter line. An underhand pass is allowed from any part of the court. The libero is, generally, the most skilled defensive player on the team. There is also a libero tracking sheet, where the referees or officiating team must keep track of whom the libero subs in and out for. There may only be one libero per set (game), although there may be a different libero in the beginning of any new set (game). Furthermore, a libero is not


title: Volleyball content: allowed to serve, according to international rules, with the exception of the NCAA women's volleyball games, where a 2004 rule change allows the libero to serve, but only in a specific rotation. That is, the libero can only serve for one person, not for all of the people for whom she goes in. That rule change was also applied to high school and junior high play soon after. Other rule changes enacted in 2000 include allowing serves in which the ball touches the net, as long as it goes over the net into the opponents' court. Also, the service area


title: Volleyball content: was expanded to allow players to serve from anywhere behind the end line but still within the theoretical extension of the sidelines. Other changes were made to lighten up calls on faults for carries and double-touches, such as allowing multiple contacts by a single player ("double-hits") on a team's first contact provided that they are a part of a single play on the ball. In 2008, the NCAA changed the minimum number of points needed to win any of the first four sets from 30 to 25 for women's volleyball (men's volleyball remained at 30 for another 3 years, switching


title: Volleyball content: to 25 in 2011.) If a fifth (deciding) set is reached, the minimum required score remains at 15. In addition, the word "game" is now referred to as "set". Changes in rules have been studied and announced by the FIVB in recent years, and they have released the updated rules in 2009. Competitive teams master six basic skills: serve, pass, set, attack, block and dig. Each of these skills comprises a number of specific techniques that have been introduced over the years and are now considered standard practice in high-level volleyball. A player stands behind the inline and serves the


title: Volleyball content: ball, in an attempt to drive it into the opponent's court. The main objective is to make it land inside the court; it is also desirable to set the ball's direction, speed and acceleration so that it becomes difficult for the receiver to handle it properly. A serve is called an "ace" when the ball lands directly onto the court or travels outside the court after being touched by an opponent. In contemporary volleyball, many types of serves are employed: Also called reception, the pass is the attempt by a team to properly handle the opponent's serve, or any form


title: Volleyball content: of attack. Proper handling includes not only preventing the ball from touching the court, but also making it reach the position where the setter is standing quickly and precisely. The skill of passing involves fundamentally two specific techniques: underarm pass, or bump, where the ball touches the inside part of the joined forearms or platform, at waist line; and overhand pass, where it is handled with the fingertips, like a set, above the head. Either are acceptable in professional and beach volleyball; however, there are much tighter regulations on the overhand pass in beach volleyball. The set is usually the


title: Volleyball content: second contact that a team makes with the ball. The main goal of setting is to put the ball in the air in such a way that it can be driven by an attack into the opponent's court. The setter coordinates the offensive movements of a team, and is the player who ultimately decides which player will actually attack the ball. As with passing, one may distinguish between an overhand and a bump set. Since the former allows for more control over the speed and direction of the ball, the bump is used only when the ball is so low


title: Volleyball content: it cannot be properly handled with fingertips, or in beach volleyball where rules regulating overhand setting are more stringent. In the case of a set, one also speaks of a front or back set, meaning whether the ball is passed in the direction the setter is facing or behind the setter. There is also a jump set that is used when the ball is too close to the net. In this case the setter usually jumps off his or her right foot straight up to avoid going into the net. The setter usually stands about ⅔ of the way from


title: Volleyball content: the left to the right of the net and faces the left (the larger portion of net that he or she can see). Sometimes a setter refrains from raising the ball for a teammate to perform an attack and tries to play it directly onto the opponent's court. This movement is called a "dump". This can only be performed when the setter is in the front row, otherwise it constitutes an illegal back court attack. The most common dumps are to 'throw' the ball behind the setter or in front of the setter to zones 2 and 4. More experienced


title: Volleyball content: setters toss the ball into the deep corners or spike the ball on the second hit. As with a set or an overhand pass, the setter/passer must be careful to touch the ball with both hands at the same time. If one hand is noticeably late to touch the ball this could result in a less effective set, as well as the referee calling a 'double hit' and giving the point to the opposing team. The attack, also known as the "spike", is usually the third contact a team makes with the ball. The object of attacking is to handle


title: Volleyball content: the ball so that it lands on the opponent's court and cannot be defended. A player makes a series of steps (the "approach"), jumps, and swings at the ball. Ideally the contact with the ball is made at the apex of the hitter's jump. At the moment of contact, the hitter's arm is fully extended above his or her head and slightly forward, making the highest possible contact while maintaining the ability to deliver a powerful hit. The hitter uses arm swing, wrist snap, and a rapid forward contraction of the entire body to drive the ball. A 'bounce' is


title: Volleyball content: a slang term for a very hard/loud spike that follows an almost straight trajectory steeply downward into the opponent's court and bounces very high into the air. A "kill" is the slang term for an attack that is not returned by the other team thus resulting in a point. Contemporary volleyball comprises a number of attacking techniques: Blocking refers to the actions taken by players standing at the net to stop or alter an opponent's attack. A block that is aimed at completely stopping an attack, thus making the ball remain in the opponent's court, is called offensive. A well-executed


title: Volleyball content: offensive block is performed by jumping and reaching to penetrate with one's arms and hands over the net and into the opponent's area. It requires anticipating the direction the ball will go once the attack takes place. It may also require calculating the best foot work to executing the "perfect" block. The jump should be timed so as to intercept the ball's trajectory prior to it crossing over the net. Palms are held deflected downward roughly 45–60 degrees toward the interior of the opponents court. A "roof" is a spectacular offensive block that redirects the power and speed of the


title: Volleyball content: attack straight down to the attacker's floor, as if the attacker hit the ball into the underside of a peaked house roof. By contrast, it is called a defensive, or "soft" block if the goal is to control and deflect the hard-driven ball up so that it slows down and becomes easier to defend. A well-executed soft-block is performed by jumping and placing one's hands above the net with no penetration into the opponent's court and with the palms up and fingers pointing backward. Blocking is also classified according to the number of players involved. Thus, one may speak of


title: Volleyball content: single (or solo), double, or triple block. Successful blocking does not always result in a "roof" and many times does not even touch the ball. While it's obvious that a block was a success when the attacker is roofed, a block that consistently forces the attacker away from his or her 'power' or preferred attack into a more easily controlled shot by the defense is also a highly successful block. At the same time, the block position influences the positions where other defenders place themselves while opponent hitters are spiking. Digging is the ability to prevent the ball from touching


title: Volleyball content: one's court after a spike or attack, particularly a ball that is nearly touching the ground. In many aspects, this skill is similar to passing, or bumping: overhand dig and bump are also used to distinguish between defensive actions taken with fingertips or with joined arms. It varies from passing however in that is it a much more reflex based skill, especially at the higher levels. It is especially important while digging for players to stay on their toes; several players choose to employ a split step to make sure they're ready to move in any direction. Some specific techniques


title: Volleyball content: are more common in digging than in passing. A player may sometimes perform a "dive", i.e., throw his or her body in the air with a forward movement in an attempt to save the ball, and land on his or her chest. When the player also slides his or her hand under a ball that is almost touching the court, this is called a "pancake". The pancake is frequently used in indoor volleyball, but rarely if ever in beach volleyball because the uneven and yielding nature of the sand court limits the chances that the ball will make a good,


title: Volleyball content: clean contact with the hand. When used correctly, it is one of the more spectacular defensive volleyball plays. Sometimes a player may also be forced to drop his or her body quickly to the floor to save the ball. In this situation, the player makes use of a specific rolling technique to minimize the chances of injuries. Volleyball is essentially a game of transition from one of the above skills to the next, with choreographed team movement between plays on the ball. These team movements are determined by the teams chosen serve receive system, offensive system, coverage system, and defensive


title: Volleyball content: system. The serve-receive system is the formation used by the receiving team to attempt to pass the ball to the designated setter. Systems can consist of 5 receivers, 4 receivers, 3 receivers, and in some cases 2 receivers. The most popular formation at higher levels is a 3 receiver formation consisting of two left sides and a libero receiving every rotation. This allows middles and right sides to become more specialized at hitting and blocking. Offensive systems are the formations used by the offense to attempt to ground the ball into the opposing court (or otherwise score points). Formations often


title: Volleyball content: include designated player positions with skill specialization (see "Player specialization", below). Popular formations include the 4-2, 6-2, and 5-1 systems (see "Formations", below). There are also several different attacking schemes teams can use to keep the opposing defense off balance. Coverage systems are the formations used by the offense to protect their court in the case of a blocked attack. Executed by the 5 offensive players not directly attacking the ball, players move to assigned positions around the attacker to dig up any ball that deflects off the block back into their own court. Popular formations include the 2-3 system


title: Volleyball content: and the 1-2-2 system. In lieu of a system, some teams just use a random coverage with the players nearest the hitter. Defensive systems are the formations used by the defense to protect against the ball being grounded into their court by the opposing team. The system will outline which players are responsible for which areas of the court depending on where the opposing team is attacking from. Popular systems include the 6-Up, 6-Back-Deep, and 6-Back-Slide defense. There are also several different blocking schemes teams can employ to disrupt the opposing teams offense. When one player is ready to serve,


title: Volleyball content: some teams will line up their other five players in a screen to obscure the view of the receiving team. This action is only illegal if the server makes use of the screen, so the call is made at the referee's discretion as to the impact the screen made on the receiving team's ability to pass the ball. The most common style of screening involves a W formation designed to take up as much horizontal space as possible. Coaching for volleyball can be classified under two main categories: match coaching and developmental coaching. The objective of match coaching is to


title: Volleyball content: win a match by managing a team's strategy. Developmental coaching emphasizes player development through the reinforcement of basic skills during exercises known as "drills." Drills promote repetition and refinement of volleyball movements, particularly in footwork patterns, body positioning relative to others, and ball contact. A coach will construct drills that simulate match situations thereby encouraging speed of movement, anticipation, timing, communication, and team-work. At the various stages of a player's career, a coach will tailor drills to meet the strategic requirements of the team. The American Volleyball Coaches Association is the largest organization in the world dedicated exclusively to volleyball


title: Volleyball content: coaching. There are 5 positions filled on every volleyball team at the elite level. Setter, Outside Hitter/Left Side Hitter, Middle Hitter, Opposite Hitter/Right Side Hitter and Libero/Defensive Specialist. Each of these positions plays a specific, key role in winning a volleyball match. At some levels where substitutions are unlimited, teams will make use of a Defensive Specialist in place of or in addition to a Libero. This position does not have unique rules like the libero position, instead, these players are used to substitute out a poor back row defender using regular substitution rules. A defensive specialist is often used


title: Volleyball content: if you have a particularly poor back court defender in right side or left side, but your team is already using a libero to take out your middles. Most often, the situation involves a team using a right side player with a big block who must be subbed out in the back row because they aren't able to effectively play back court defense. Similarly, teams might use a Serving Specialist to sub out a poor server. The three standard volleyball formations are known as "4–2", "6–2" and "5–1", which refers to the number of hitters and setters respectively. 4–2 is


title: Volleyball content: a basic formation used only in beginners' play, while 5–1 is by far the most common formation in high-level play. The 4–2 formation has four hitters and two setters. The setters usually set from the middle front or right front position. The team will therefore have two front-row attackers at all times. In the international 4–2, the setters set from the right front position. The international 4–2 translates more easily into other forms of offense. The setters line up opposite each other in the rotation. The typical lineup has two outside hitters. By aligning like positions opposite themselves in the


title: Volleyball content: rotation, there will always be one of each position in the front and back rows. After service, the players in the front row move into their assigned positions, so that the setter is always in middle front. Alternatively, the setter moves into the right front and has both a middle and an outside attacker; the disadvantage here lies in the lack of an offside hitter, allowing one of the other team's blockers to "cheat in" on a middle block. The clear disadvantage to this offensive formation is that there are only two attackers, leaving a team with fewer offensive weapons.


title: Volleyball content: Another aspect is to see the setter as an attacking force, albeit a weakened force, because when the setter is in the front court they are able to 'tip' or 'dump', so when the ball is close to the net on the second touch, the setter may opt to hit the ball over with one hand. This means that the blocker who would otherwise not have to block the setter is engaged and may allow one of the hitters to have an easier attack. In the 6–2 formation, a player always comes forward from the back row to set. The


title: Volleyball content: three front row players are all in attacking positions. Thus, all six players act as hitters at one time or another, while two can act as setters. So the 6–2 formation is actually a 4–2 system, but the back-row setter penetrates to set. The 6–2 lineup thus requires two setters, who line up opposite to each other in the rotation. In addition to the setters, a typical lineup will have two middle hitters and two outside hitters. By aligning like positions opposite themselves in the rotation, there will always be one of each position in the front and back rows.


title: Volleyball content: After service, the players in the front row move into their assigned positions. The advantage of the 6–2 is that there are always three front-row hitters available, maximizing the offensive possibilities. However, not only does the 6–2 require a team to possess two people capable of performing the highly specialized role of setter, it also requires both of those players to be effective offensive hitters when not in the setter position. At the international level, only the Cuban National Women's Team employs this kind of formation. It is also used by NCAA teams in Division III men's play and women's


title: Volleyball content: play in all divisions, partially due to the variant rules used which allow more substitutions per set than the 6 allowed in the standard rules—12 in matches involving two Division III men's teams and 15 for all women's play. The 5–1 formation has only one player who assumes setting responsibilities regardless of his or her position in the rotation. The team will therefore have three front-row attackers when the setter is in the back row, and only two when the setter is in the front row, for a total of five possible attackers. The player opposite the setter in a


title: Volleyball content: 5–1 rotation is called the "opposite hitter". In general, opposite hitters do not pass; they stand behind their teammates when the opponent is serving. The opposite hitter may be used as a third attack option (back-row attack) when the setter is in the front row: this is the normal option used to increase the attack capabilities of modern volleyball teams. Normally the opposite hitter is the most technically skilled hitter of the team. Back-row attacks generally come from the back-right position, known as zone 1, but are increasingly performed from back-center in high-level play. The big advantage of this system


title: Volleyball content: is that the setter always has 3 hitters to vary sets with. If the setter does this well, the opponent's middle blocker may not have enough time to block with the outside blocker, increasing the chance for the attacking team to make a point. There is another advantage, the same as that of a 4–2 formation: when the setter is a front-row player, he or she is allowed to jump and "dump" the ball onto the opponent's side. This too can confuse the opponent's blocking players: the setter can jump and dump or can set to one of the hitters.


title: Volleyball content: A good setter knows this and thus won't only jump to dump or to set for a quick hit, but when setting outside as well to confuse the opponent. The 5–1 offense is actually a mix of 6–2 and 4–2: when the setter is in the front row, the offense looks like a 4–2; when the setter is in the back row, the offense looks like a 6–2. In 2017, a new volleyball union was formed in response to dissatisfaction with the organization and structure of professional beach volleyball tournaments. The union is named the International Beach Volleyball Players Association,


title: Volleyball content: and it consists of almost 100 professional players. IBVPA claims its goal is to help athletes and provide them with the means to enjoy playing volleyball by improving the way the sport is run. Another controversy within the sport is the issue of the inclusion of transgender players. With transgender athletes such as Tifanny Abreu joining professional volleyball teams alongside other non-transgender teammates, many professionals, sports analysts, and fans of volleyball are either expressing concerns about the legitimacy and fairness of having transgender players on a team or expressing support for the transgender people's efforts. There are many variations on


title: Volleyball content: the basic rules of volleyball. By far the most popular of these is beach volleyball, which is played on sand with two people per team, and rivals the main sport in popularity. Some games related to volleyball include: Volleyball Volleyball is a team sport in which two teams of six players are separated by a net. Each team tries to score points by grounding a ball on the other team's court under organized rules. It has been a part of the official program of the Summer Olympic Games since 1964. The complete rules are extensive, but simply, play proceeds as


title: Volcano content: Volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. Therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has


title: Volcano content: volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, e.g., in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism. Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth. Volcanoes are usually not created where two tectonic plates slide past one


title: Volcano content: another. Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption. One such hazard is that volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the high operating temperature; the melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine. Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere (or troposphere); however, they also absorb heat radiated from the Earth, thereby warming the


title: Volcano content: upper atmosphere (or stratosphere). Historically, volcanic winters have caused catastrophic famines. The word "volcano" is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled "vulcanology". At the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Because the crust is very thin at these ridges due to the pull of the tectonic plates, the release of


title: Volcano content: pressure leads to adiabatic expansion (without transfer of heat or matter) and the partial melting of the mantle, causing volcanism and creating new oceanic crust. Most divergent plate boundaries are at the bottom of the oceans; therefore, most volcanic activity on the Earth is submarine, forming new seafloor. Black smokers (also known as deep sea vents) are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed; for example, Iceland. Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the oceanic plate


title: Volcano content: subducts, or submerges, under the continental plate, forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the melting temperature of the overlying mantle wedge, thus creating magma. This magma tends to be extremely viscous because of its high silica content, so it often does not attain the surface but cools and solidifies at depth. When it does reach the surface, however, a volcano is formed. Typical examples are Mount Etna and the volcanoes in the Pacific Ring of Fire. Hotspots are volcanic areas believed to be formed by mantle


title: Volcano content: plumes, which are hypothesized to be columns of hot material rising from the core-mantle boundary in a fixed space that causes large-volume melting. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume. The Hawaiian Islands are said to have been formed in such a manner; so has the Snake River Plain, with the Yellowstone Caldera being the part of the North American plate above the hot spot. This theory, however, has been doubted. The most common perception of a volcano is of a conical mountain, spewing lava


title: Volcano content: and poisonous gases from a crater at its summit; however, this describes just one of the many types of volcano. The features of volcanoes are much more complicated and their structure and behavior depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have landscape features such as massive plateaus. Vents that issue volcanic material (including lava and ash) and gases (mainly steam and magmatic gases) can develop anywhere on the landform and may give rise to smaller cones such as Puu Ōō on a flank of Hawaii's


title: Volcano content: Kīlauea. Other types of volcano include cryovolcanoes (or ice volcanoes), particularly on some moons of Jupiter, Saturn, and Neptune; and mud volcanoes, which are formations often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes except when the mud volcano is actually a vent of an igneous volcano. Volcanic fissure vents are flat, linear fractures through which lava emerges. Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent. They generally do not


title: Volcano content: explode catastrophically. Since low-viscosity magma is typically low in silica, shield volcanoes are more common in oceanic than continental settings. The Hawaiian volcanic chain is a series of shield cones, and they are common in Iceland, as well. Lava domes are built by slow eruptions of highly viscous lava. They are sometimes formed within the crater of a previous volcanic eruption, as in the case of Mount Saint Helens, but can also form independently, as in the case of Lassen Peak. Like stratovolcanoes, they can produce violent, explosive eruptions, but their lava generally does not flow far from the originating


title: Volcano content: vent. Cryptodomes are formed when viscous lava is forced upward causing the surface to bulge. The 1980 eruption of Mount St. Helens was an example; lava beneath the surface of the mountain created an upward bulge which slid down the north side of the mountain. Volcanic cones or cinder cones result from eruptions of mostly small pieces of scoria and pyroclastics (both resemble cinders, hence the name of this volcano type) that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 meters high. Most cinder cones erupt only once.


title: Volcano content: Cinder cones may form as flank vents on larger volcanoes, or occur on their own. Parícutin in Mexico and Sunset Crater in Arizona are examples of cinder cones. In New Mexico, Caja del Rio is a volcanic field of over 60 cinder cones. Based on satellite images it was suggested that cinder cones might occur on other terrestrial bodies in the Solar system too; on the surface of Mars and the Moon. Stratovolcanoes or composite volcanoes are tall conical mountains composed of lava flows and other ejecta in alternate layers, the strata that gives rise to the name. Stratovolcanoes are


title: Volcano content: also known as composite volcanoes because they are created from multiple structures during different kinds of eruptions. Strato/composite volcanoes are made of cinders, ash, and lava. Cinders and ash pile on top of each other, lava flows on top of the ash, where it cools and hardens, and then the process repeats. Classic examples include Mount Fuji in Japan, Mayon Volcano in the Philippines, and Mount Vesuvius and Stromboli in Italy. Throughout recorded history, ash produced by the explosive eruption of stratovolcanoes has posed the greatest volcanic hazard to civilizations. Not only do stratovolcanoes have greater pressure buildup from the


title: Volcano content: underlying lava flow than shield volcanoes, but their fissure vents and monogenetic volcanic fields (volcanic cones) also have more powerful eruptions because they are often under extension. They are also steeper than shield volcanoes, with slopes of 30–35° compared to slopes of generally 5–10°, and their loose tephra are material for dangerous lahars. Large pieces of tephra are called volcanic bombs. Big bombs can measure more than 4 feet(1.2 meters) across and weigh several tons. A supervolcano usually has a large caldera and can produce devastation on an enormous, sometimes continental, scale. Such volcanoes are able to severely cool global


title: Volcano content: temperatures for many years after the eruption due to the huge volumes of sulfur and ash released into the atmosphere. They are the most dangerous type of volcano. Examples include Yellowstone Caldera in Yellowstone National Park and Valles Caldera in New Mexico (both western United States); Lake Taupo in New Zealand; Lake Toba in Sumatra, Indonesia; and Ngorongoro Crater in Tanzania. Because of the enormous area they may cover, supervolcanoes are hard to identify centuries after an eruption. Similarly, large igneous provinces are also considered supervolcanoes because of the vast amount of basalt lava erupted (even though the lava flow


title: Volcano content: is non-explosive). Submarine volcanoes are common features of the ocean floor. In shallow water, active volcanoes disclose their presence by blasting steam and rocky debris high above the ocean's surface. In the ocean's deep, the tremendous weight of the water above prevents the explosive release of steam and gases; however, they can be detected by hydrophones and discoloration of water because of volcanic gases. Pillow lava is a common eruptive product of submarine volcanoes and is characterized by thick sequences of discontinuous pillow-shaped masses which form under water. Even large submarine eruptions may not disturb the ocean surface due to


title: Volcano content: the rapid cooling effect and increased buoyancy of water (as compared to air) which often causes volcanic vents to form steep pillars on the ocean floor. Hydrothermal vents are common near these volcanoes, and some support peculiar ecosystems based on dissolved minerals. Over time, the formations created by submarine volcanoes may become so large that they break the ocean surface as new islands or floating pumice rafts. Subglacial volcanoes develop underneath icecaps. They are made up of flat lava which flows at the top of extensive pillow lavas and palagonite. When the icecap melts, the lava on top collapses, leaving


title: Volcano content: a flat-topped mountain. These volcanoes are also called table mountains, tuyas, or (uncommonly) mobergs. Very good examples of this type of volcano can be seen in Iceland, however, there are also tuyas in British Columbia. The origin of the term comes from Tuya Butte, which is one of the several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Butte was the first such landform analyzed and so its name has entered the geological literature for this kind of volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual


title: Volcano content: landscape, which lies north of Tuya Lake and south of the Jennings River near the boundary with the Yukon Territory. Mud volcanoes or mud domes are formations created by geo-excreted liquids and gases, although there are several processes which may cause such activity. The largest structures are 10 kilometers in diameter and reach 700 meters high. Another way of classifying volcanoes is by the "composition of material erupted" (lava), since this affects the shape of the volcano. Lava can be broadly classified into four different compositions: Two types of lava are named according to the surface texture: Aa (pronounced )


title: Volcano content: and pāhoehoe (), both Hawaiian words. Aa is characterized by a rough, clinkery surface and is the typical texture of viscous lava flows. However, even basaltic or mafic flows can be erupted as aa flows, particularly if the eruption rate is high and the slope is steep. Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Usually, only mafic flows will erupt as pāhoehoe, since they often erupt at higher temperatures or have the proper chemical make-up to allow them to flow with greater fluidity. A popular way


title: Volcano content: of classifying magmatic volcanoes is by their frequency of eruption, with those that erupt regularly called active, those that have erupted in historical times but are now quiet called dormant or inactive, and those that have not erupted in historical times called extinct. However, these popular classifications—extinct in particular—are practically meaningless to scientists. They use classifications which refer to a particular volcano's formative and eruptive processes and resulting shapes. There is no consensus among volcanologists on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes


title: Volcano content: meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of eruption. Given the long lifespan of such volcanoes, they are very active. By human lifespans, however, they are not. Scientists usually consider a volcano to be "erupting" or "likely to erupt" if it is currently erupting, or showing signs of unrest such as unusual earthquake activity or significant new gas emissions. Most scientists consider a volcano "active" if it has erupted in the last 10,000


title: Volcano content: years (Holocene times) – the Smithsonian Global Volcanism Program uses this definition of "active". Most volcanoes are situated on the Pacific Ring of Fire. An estimated 500 million people live near active volcanoes. "Historical time" (or recorded history) is another timeframe for "active". The "Catalogue of the Active Volcanoes of the World", published by the International Association of Volcanology, uses this definition, by which there are more than 500 active volcanoes. However, the span of recorded history differs from region to region. In China and the Mediterranean, it reaches back nearly 3,000 years, but in the Pacific Northwest of the


title: Volcano content: United States and Canada, it reaches back less than 300 years, and in Hawaii and New Zealand, only around 200 years. As of 2013, the following are considered Earth's most active volcanoes: , the longest ongoing (but not necessarily continuous) volcanic eruptive phases are: Other very active volcanoes include: Extinct volcanoes are those that scientists consider unlikely to erupt again because the volcano no longer has a magma supply. Examples of extinct volcanoes are many volcanoes on the Hawaiian – Emperor seamount chain in the Pacific Ocean (although some volcanoes at the eastern end of the chain are active), Hohentwiel


title: Volcano content: in Germany, Shiprock in New Mexico, and Zuidwal volcano in the Netherlands. Edinburgh Castle in Scotland is famously located atop an extinct volcano. Otherwise, whether a volcano is truly extinct is often difficult to determine. Since "supervolcano" calderas can have eruptive lifespans sometimes measured in millions of years, a caldera that has not produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct. Some volcanologists refer to extinct volcanoes as inactive, though the term is now more commonly used for dormant volcanoes once thought to be extinct. It is difficult to distinguish


title: Volcano content: an extinct volcano from a dormant (inactive) one. Dormant volcanoes are those that have not erupted for thousands of years, but are likely to erupt again in the future. Volcanoes are often considered to be extinct if there are no written records of its activity. Nevertheless, volcanoes may remain dormant for a long period of time. For example, Yellowstone has a repose/recharge period of around 700,000 years, and Toba of around 380,000 years. Vesuvius was described by Roman writers as having been covered with gardens and vineyards before its eruption of 79 CE, which destroyed the towns of Herculaneum and


title: Volcano content: Pompeii. Before its catastrophic eruption of 1991, Pinatubo was an inconspicuous volcano, unknown to most people in the surrounding areas. Two other examples are the long-dormant Soufrière Hills volcano on the island of Montserrat, thought to be extinct before activity resumed in 1995, and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE and had long been thought to be extinct. The three common popular classifications of volcanoes can be subjective and some volcanoes thought to have been extinct have erupted again. To help prevent people from falsely believing they are not


title: Volcano content: at risk when living on or near a volcano, countries have adopted new classifications to describe the various levels and stages of volcanic activity. Some alert systems use different numbers or colors to designate the different stages. Other systems use colors and words. Some systems use a combination of both. The United States Geological Survey (USGS) has adopted a common system nationwide for characterizing the level of unrest and eruptive activity at volcanoes. The new volcano alert-level system classifies volcanoes now as being in a normal, advisory, watch or warning stage. Additionally, colors are used to denote the amount of


title: Volcano content: ash produced. The Decade Volcanoes are 16 volcanoes identified by the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) as being worthy of particular study in light of their history of large, destructive eruptions and proximity to populated areas. They are named Decade Volcanoes because the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction (the 1990s). The 16 current Decade Volcanoes are The Deep Earth Carbon Degassing Project, an initiative of the Deep Carbon Observatory, monitors nine volcanoes, two of which are Decade volcanoes. The focus of the Deep Earth


title: Volcano content: Carbon Degassing Project is to use Multi-Component Gas Analyzer System instruments to measure CO/SO ratios in real-time and in high-resolution to allow detection of the pre-eruptive degassing of rising magmas, improving prediction of volcanic activity. There are many different types of volcanic eruptions and associated activity: phreatic eruptions (steam-generated eruptions), explosive eruption of high-silica lava (e.g., rhyolite), effusive eruption of low-silica lava (e.g., basalt), pyroclastic flows, lahars (debris flow) and carbon dioxide emission. All of these activities can pose a hazard to humans. Earthquakes, hot springs, fumaroles, mud pots and geysers often accompany volcanic activity. The concentrations of different volcanic


title: Volcano content: gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides. Large, explosive volcanic eruptions inject water vapor (HO), carbon dioxide (CO), sulfur dioxide (SO), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pumice) into the stratosphere to heights of 16–32 kilometres (10–20 mi)


title: Volcano content: above the Earth's surface. The most significant impacts from these injections come from the conversion of sulfur dioxide to sulfuric acid (HSO), which condenses rapidly in the stratosphere to form fine sulfate aerosols. The SO emissions alone of two different eruptions are sufficient to compare their potential climatic impact. The aerosols increase the Earth's albedo—its reflection of radiation from the Sun back into space—and thus cool the Earth's lower atmosphere or troposphere; however, they also absorb heat radiated up from the Earth, thereby warming the stratosphere. Several eruptions during the past century have caused a decline in the average temperature


title: Volcano content: at the Earth's surface of up to half a degree (Fahrenheit scale) for periods of one to three years; sulfur dioxide from the eruption of Huaynaputina probably caused the Russian famine of 1601–1603. A volcanic winter is thought to have taken place around 70,000 years ago after the supereruption of Lake Toba on Sumatra island in Indonesia. According to the Toba catastrophe theory to which some anthropologists and archeologists subscribe, it had global consequences, killing most humans then alive and creating a population bottleneck that affected the genetic inheritance of all humans today. It has been suggested that volcanic activity


title: Volcano content: caused or contributed to the End-Ordovician, Permian-Triassic, Late Devonian mass extinctions, and possibly others. The massive eruptive event which formed the Siberian Traps, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for a million years and is considered to be the likely cause of the "Great Dying" about 250 million years ago, which is estimated to have killed 90% of species existing at the time. The 1815 eruption of Mount Tambora created global climate anomalies that became known as the "Year Without a Summer" because of the effect on North


title: Volcano content: American and European weather. Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in one of the worst famines of the 19th century. The freezing winter of 1740–41, which led to widespread famine in northern Europe, may also owe its origins to a volcanic eruption. Sulfate aerosols promote complex chemical reactions on their surfaces that alter chlorine and nitrogen chemical species in the stratosphere. This effect, together with increased stratospheric chlorine levels from chlorofluorocarbon pollution, generates chlorine monoxide (ClO), which destroys ozone (O). As the aerosols grow and coagulate, they settle down into the upper troposphere


title: Volcano content: where they serve as nuclei for cirrus clouds and further modify the Earth's radiation balance. Most of the hydrogen chloride (HCl) and hydrogen fluoride (HF) are dissolved in water droplets in the eruption cloud and quickly fall to the ground as acid rain. The injected ash also falls rapidly from the stratosphere; most of it is removed within several days to a few weeks. Finally, explosive volcanic eruptions release the greenhouse gas carbon dioxide and thus provide a deep source of carbon for biogeochemical cycles. Gas emissions from volcanoes are a natural contributor to acid rain. Volcanic activity releases about


title: Volcano content: 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year. Volcanic eruptions may inject aerosols into the Earth's atmosphere. Large injections may cause visual effects such as unusually colorful sunsets and affect global climate mainly by cooling it. Volcanic eruptions also provide the benefit of adding nutrients to soil through the weathering process of volcanic rocks. These fertile soils assist the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and solidifies upon contact with the water. Ash thrown into the air by eruptions can present


title: Volcano content: a hazard to aircraft, especially jet aircraft where the particles can be melted by the high operating temperature; the melted particles then adhere to the turbine blades and alter their shape, disrupting the operation of the turbine. Dangerous encounters in 1982 after the eruption of Galunggung in Indonesia, and 1989 after the eruption of Mount Redoubt in Alaska raised awareness of this phenomenon. Nine Volcanic Ash Advisory Centers were established by the International Civil Aviation Organization to monitor ash clouds and advise pilots accordingly. The 2010 eruptions of Eyjafjallajökull caused major disruptions to air travel in Europe. The Earth's Moon


title: Volcano content: has no large volcanoes and no current volcanic activity, although recent evidence suggests it may still possess a partially molten core. However, the Moon does have many volcanic features such as maria (the darker patches seen on the moon), rilles and domes. The planet Venus has a surface that is 90% basalt, indicating that volcanism played a major role in shaping its surface. The planet may have had a major global resurfacing event about 500 million years ago, from what scientists can tell from the density of impact craters on the surface. Lava flows are widespread and forms of volcanism


title: Volcano content: not present on Earth occur as well. Changes in the planet's atmosphere and observations of lightning have been attributed to ongoing volcanic eruptions, although there is no confirmation of whether or not Venus is still volcanically active. However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank. There are several extinct volcanoes on Mars, four of which are vast shield volcanoes far bigger than any on Earth. They include Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus


title: Volcano content: Mons, and Pavonis Mons. These volcanoes have been extinct for many millions of years, but the European "Mars Express" spacecraft has found evidence that volcanic activity may have occurred on Mars in the recent past as well. Jupiter's moon Io is the most volcanically active object in the solar system because of tidal interaction with Jupiter. It is covered with volcanoes that erupt sulfur, sulfur dioxide and silicate rock, and as a result, Io is constantly being resurfaced. Its lavas are the hottest known anywhere in the solar system, with temperatures exceeding 1,800 K (1,500 °C). In February 2001, the


title: Volcano content: largest recorded volcanic eruptions in the solar system occurred on Io. Europa, the smallest of Jupiter's Galilean moons, also appears to have an active volcanic system, except that its volcanic activity is entirely in the form of water, which freezes into ice on the frigid surface. This process is known as cryovolcanism, and is apparently most common on the moons of the outer planets of the solar system. In 1989 the Voyager 2 spacecraft observed cryovolcanoes (ice volcanoes) on Triton, a moon of Neptune, and in 2005 the Cassini–Huygens probe photographed fountains of frozen particles erupting from Enceladus, a moon


title: Volcano content: of Saturn. The ejecta may be composed of water, liquid nitrogen, ammonia, dust, or methane compounds. Cassini–Huygens also found evidence of a methane-spewing cryovolcano on the Saturnian moon Titan, which is believed to be a significant source of the methane found in its atmosphere. It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar. A 2010 study of the exoplanet COROT-7b, which was detected by transit in 2009, suggested that tidal heating from the host star very close to the planet and neighboring planets could generate intense volcanic activity similar to that found on Io.


title: Volcano content: Many ancient accounts ascribe volcanic eruptions to supernatural causes, such as the actions of gods or demigods. To the ancient Greeks, volcanoes' capricious power could only be explained as acts of the gods, while 16th/17th-century German astronomer Johannes Kepler believed they were ducts for the Earth's tears. One early idea counter to this was proposed by Jesuit Athanasius Kircher (1602–1680), who witnessed eruptions of Mount Etna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal. Various explanations


title: Volcano content: were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemical reactions and a thin layer of molten rock near the surface. Volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major,


title: "Vietnam War" content: and cities, along with mass defections among ARVN units, who were on holiday leave during the truce period. The Tet Offensive began on 30 January 1968, as over 100 cities were attacked by over 85,000 enemy troops, including assaults on key military installations, headquarters, and government buildings and offices, including the U.S. Embassy in Saigon. U.S. and South Vietnamese forces were initially shocked by the scale, intensity and deliberative planning of the urban offensive, as infiltration of personnel and weapons into the cities was accomplished covertly; the offensive constituted an intelligence failure on the scale of Pearl Harbor. Most cities


title: "Video art" content: the most commonly used recording technology in much of the form history into the 1990s. With the advent of digital recording equipment, many artists began to explore digital technology as a new way of expression. One of the key differences between video art and theatrical cinema is that video art does not necessarily rely on many of the conventions that define theatrical cinema. Video art may not employ the use of actors, may contain no dialogue, may have no discernible narrative or plot, or adhere to any of the other conventions that generally define motion pictures as entertainment. This distinction


title: "Video game console" content: ways. NEC and Sega released CD add-ons to their consoles in the form of the TurboGrafx-CD and Sega CD, but both were only moderately successful. NEC also released the TurboDuo which combined the TurboGrafx-16 and its TurboGrafx-CD add-on (along with the RAM and BIOS upgrade from the Super System Card) into one unit. SNK released a third version of the NeoGeo, the Neo Geo CD, allowing the company to release its games on a cheaper medium than the AES's expensive cartridges, but it reached the market after Nintendo and Sega had already sold tens of millions of consoles each. Nintendo


title: "Vince Lombardi" content: longtime assistant, but the Packers finished at 6–7–1 and out of the four team NFL playoffs. In 1969, Lombardi became head coach and general manager of the Washington Redskins. The Redskins would finish with a record of 7–5–2, their first winning record in 14 years. The foundation that Lombardi put in place helped Washington's early 1970s success under former Los Angeles Rams Coach George Allen. In the fall of 1934 Lombardi's roommate Jim Lawlor introduced him to his cousin's relative, Marie Planitz. When Marie announced her ardent desire to marry Lombardi, her status-conscious stockbroker father didn't like the idea of


title: "Veit Stoss" content: Veit Stoss Veit Stoss (also: "Veit Stoß" and "Stuoss"; ; before 1450 – about 20 September 1533) was a leading German sculptor, mostly in wood, whose career covered the transition between the late Gothic and the Northern Renaissance. His style emphasized pathos and emotion, helped by his virtuoso carving of billowing drapery; it has been called "late Gothic Baroque". He had a large workshop and in addition to his own works there are a number by pupils. He is best known for the altarpiece in St. Mary's Basilica in Kraków, Poland. Stoss was born at Horb am Neckar before 1450;


title: "Vocal cords" content: Vocal cords The vocal cords, also known as vocal folds, are folds of tissue in the throat that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speech or singing, the folds are controlled via the vagus nerve. They are composed of twin infoldings of mucous membrane stretched horizontally, from back to front, across the larynx. They vibrate, modulating the flow of air being expelled from the lungs during phonation. The vocal cords are composed of twin infoldings of 3 distinct tissues: The outer layer is


title: "Battle of Monte Cassino" content: On 15 May, the British 78th Division came into the British XIII Corps line from reserve passing through the bridgehead divisions to execute the turning move to isolate Cassino from the Liri valley. On 17 May, Polish II Corps launched their second attack on Monte Cassino. Under constant artillery and mortar fire from the strongly fortified German positions and with little natural cover for protection, the fighting was fierce and at times hand-to-hand. With their line of supply threatened by the Allied advance in the Liri valley, the Germans decided to withdraw from the Cassino heights to the new defensive


title: Wargame content: of the end of the world', first published in 1966 and still published today by Flying Buffalo. It does not simulate how any actual nuclear exchange would happen, but it is still structured unlike most card games because of the way it deals with its subject. In the late 1970s Battleline Publications (a board wargame company) produced two card games, "Naval War" and "Armor Supremacy". The first was fairly popular in wargaming circles, and is a light system of naval combat, though again not depicting any 'real' situation (players may operate ships from opposing navies side-by-side). "Armor Supremacy" was not


title: Wargame content: games, such as Duel2 (formerly known as Duelmasters), Hyborian War, and Forgotten Realms: War of the Avatars. Since e-mail is faster than the standard postal service, the rise of the Internet saw a shift of people playing board wargames from play-by-mail (PBM) to play-by-email (PBEM) or play-by-web (PBW). The mechanics were the same, merely the medium was faster. At this time, turn-based strategy computer games still had a decent amount of popularity, and many started explicitly supporting the sending of saved-game files through email (instead of needing to find the file to send to the opponent by hand). As with


title: Whisky content: Whisky Whisky or whiskey is a type of distilled alcoholic beverage made from fermented grain mash. Various grains (which may be malted) are used for different varieties, including barley, corn, rye, and wheat. Whisky is typically aged in wooden casks, generally made of charred white oak. Whisky is a strictly regulated spirit worldwide with many classes and types. The typical unifying characteristics of the different classes and types are the fermentation of grains, distillation, and aging in wooden barrels. The word "whisky" (or "whiskey") is an anglicisation of the Classical Gaelic word "uisce" (or "uisge") meaning "water" (now written as


title: Whisky content: "uisce" in Irish Gaelic, and "uisge" in Scottish Gaelic). Distilled alcohol was known in Latin as "aqua vitae" ("water of life"). This was translated into Old Irish as ' ("water of life"), which became ' in Irish and "" in Scottish Gaelic. Early forms of the word in English included "uskebeaghe" (1581), "usquebaugh" (1610), "usquebath" (1621), and "usquebae" (1715). Much is made of the word's two spellings: "whisky" and "whiskey". There are two schools of thought on the issue. One is that the spelling difference is simply a matter of regional language convention for the spelling of a word, indicating


title: Whisky content: that the spelling varies depending on the intended audience or the background or personal preferences of the writer (like the difference between "color" and "colour"; or "recognize" and "recognise"), and the other is that the spelling should depend on the style or origin of the spirit being described. There is general agreement that when quoting the proper name printed on a label, the spelling on the label should not be altered. The spelling "whiskey" is common in Ireland and the United States, while "whisky" is used in all other whisky producing countries. In the US, the usage has not always


title: Whisky content: been consistent. From the late eighteenth century to the mid twentieth century, American writers used both spellings interchangeably until the introduction of newspaper style guides. Since the 1960s, American writers have increasingly used "whiskey" as the accepted spelling for aged grain spirits made in the US and "whisky" for aged grain spirits made outside the US. However, some prominent American brands, such as George Dickel, Maker's Mark, and Old Forester (all made by different companies), use the "whisky" spelling on their labels, and the "Standards of Identity for Distilled Spirits", the legal regulations for spirit in the US, also use


title: Whisky content: the "whisky" spelling throughout. "Scotch" is the internationally recognized term for "Scotch whisky". It is possible that distillation was practised by the Babylonians in Mesopotamia in the 2nd millennium BC, with perfumes and aromatics being distilled, but this is subject to uncertain and disputed interpretations of evidence. The earliest certain chemical distillations were by Greeks in Alexandria in the 1st century AD, but these were not distillations of alcohol. The medieval Arabs adopted the distillation technique of the Alexandrian Greeks, and written records in Arabic begin in the 9th century, but again these were not distillations of alcohol. Distilling technology


title: Whisky content: passed from the medieval Arabs to the medieval Latins, with the earliest records in Latin in the early 12th century. The earliest records of the distillation of alcohol are in Italy in the 13th century, where alcohol was distilled from wine. An early description of the technique was given by Ramon Llull (1232 – 1315). Its use spread through medieval monasteries, largely for medicinal purposes, such as the treatment of colic and smallpox. The art of distillation spread to Ireland and Scotland no later than the 15th century, as did the common European practice of distilling "aqua vitae", spirit alcohol,


title: Whisky content: primarily for medicinal purposes. The practice of medicinal distillation eventually passed from a monastic setting to the secular via professional medical practitioners of the time, The Guild of Barber Surgeons. The earliest mention of whisky in Ireland comes from the seventeenth-century "Annals of Clonmacnoise", which attributes the death of a chieftain in 1405 to "taking a surfeit of aqua vitae" at Christmas. In Scotland, the first evidence of whisky production comes from an entry in the "Exchequer Rolls" for 1494 where malt is sent "To Friar John Cor, by order of the king, to make aquavitae", enough to make about


title: Whisky content: 500 bottles. James IV of Scotland (r. 1488–1513) reportedly had a great liking for Scotch whisky, and in 1506 the town of Dundee purchased a large amount of whisky from the Guild of Barber Surgeons, which held the monopoly on production at the time. Between 1536 and 1541, King Henry VIII of England dissolved the monasteries, sending their monks out into the general public. Whisky production moved out of a monastic setting and into personal homes and farms as newly independent monks needed to find a way to earn money for themselves. The distillation process was still in its infancy;


title: Whisky content: whisky itself was not allowed to age, and as a result tasted very raw and brutal compared to today's versions. Renaissance-era whisky was also very potent and not diluted. Over time whisky evolved into a much smoother drink. With a license to distill Irish whiskey from 1608, the Old Bushmills Distillery in Northern Ireland is the oldest licensed whiskey distillery in the world. In 1707, the Acts of Union merged England and Scotland, and thereafter taxes on it rose dramatically. After the English Malt Tax of 1725, most of Scotland's distillation was either shut down or forced underground. Scotch whisky


title: Whisky content: was hidden under altars, in coffins, and in any available space to avoid the governmental excisemen or revenuers. Scottish distillers, operating out of homemade stills, took to distilling whisky at night when the darkness hid the smoke from the stills. For this reason, the drink became known as moonshine. At one point, it was estimated that over half of Scotland's whisky output was illegal. In America, whisky was used as currency during the American Revolution; George Washington operated a large distillery at Mount Vernon. Given the distances and primitive transportation network of colonial America, farmers often found it easier and


title: Whisky content: more profitable to convert corn to whisky and transport it to market in that form. It also was a highly coveted sundry and when an additional excise tax was levied against it in 1791, the Whiskey Rebellion erupted. The drinking of Scotch whisky was introduced to India in the nineteenth century. The first distillery in India was built by Edward Dyer at Kasauli in the late 1820s. The operation was soon shifted to nearby Solan (close to the British summer capital Shimla), as there was an abundant supply of fresh spring water there. In 1823, the UK passed the Excise


title: Whisky content: Act, legalizing the distillation (for a fee), and this put a practical end to the large-scale production of Scottish moonshine. In 1831, Aeneas Coffey patented the Coffey still, allowing for cheaper and more efficient distillation of whisky. In 1850, Andrew Usher began producing a blended whisky that mixed traditional pot still whisky with that from the new Coffey still. The new distillation method was scoffed at by some Irish distillers, who clung to their traditional pot stills. Many Irish contended that the new product was, in fact, not whisky at all. By the 1880s, the French brandy industry was devastated


title: Whisky content: by the phylloxera pest that ruined much of the grape crop; as a result, whisky became the primary liquor in many markets. During the Prohibition era in the United States lasting from 1920 to 1933, all alcohol sales were banned in the country. The federal government made an exemption for whisky prescribed by a doctor and sold through licensed pharmacies. During this time, the Walgreens pharmacy chain grew from 20 retail stores to almost 400. A still for making whisky is usually made of copper, since it removes sulfur-based compounds from the alcohol that would make it unpleasant to drink.


title: Whisky content: Modern stills are made of stainless steel with copper innards (piping, for example, will be lined with copper along with copper plate inlays along still walls). The simplest standard distillation apparatus is commonly known as a pot still, consisting of a single heated chamber and a vessel to collect purified alcohol. Column stills are frequently used in the production of grain whisky and are the most commonly used type of still in the production of bourbon and other American whiskeys. Column stills behave like a series of single pot stills, formed in a long vertical tube. Whereas a single pot


title: Whisky content: still charged with wine might yield a vapour enriched to 40–60% alcohol, a column still can achieve a vapour alcohol content of 95.6%; an azeotropic mixture of alcohol and water. Whiskies do not mature in the bottle, only in the cask, so the "age" of a whisky is only the time between distillation and bottling. This reflects how much the cask has interacted with the whisky, changing its chemical makeup and taste. Whiskies that have been bottled for many years may have a rarity value, but are not "older" and not necessarily "better" than a more recent whisky that matured


title: Whisky content: in wood for a similar time. After a decade or two, additional aging in a barrel does not necessarily improve a whisky. While aging in wooden casks, especially American oak and French oak casks, whisky undergoes six processes that contribute to its final flavor: extraction, evaporation, oxidation, concentration, filtration, and colouration. Extraction in particular results in whisky acquiring a number of compounds, including aldehydes and acids such as vanillin, vanillic acid, and syringaldehyde. Distillers will sometimes age their whiskey in barrels previously used to age other spirits, such as rum or sherry, to impart particular flavours. Most whiskies are sold


title: Whisky content: at or near an alcoholic strength of 40% abv, which is the statutory minimum in some countries – although the strength can vary, and cask-strength whisky may have as much as twice that alcohol percentage. Whisky is probably the best known of Scotland's manufactured products. Exports have increased by 87% in the decade to 2012 and it contributes over £4.25 billion to the UK economy, making up a quarter of all its food and drink revenues. In 2012, the US was the largest market for Scotch whisky (£655 million), followed by France (£535 million). It is also one of the


title: Whisky content: UK's overall top five manufacturing export earners and it supports around 35,000 jobs. Principal whisky producing areas include Speyside and the Isle of Islay, where there are eight distilleries providing a major source of employment. In many places, the industry is closely linked to tourism, with many distilleries also functioning as attractions worth £30 million GVA each year. In 2011, 70% of Canadian whisky was exported, with about 60% going to the US, and the rest mostly to Europe and Asia. 15 million cases of Canadian whisky were sold in the US in 2011. Whisky or whisky-like products are produced


title: Whisky content: in most grain-growing areas. They differ in base product, alcoholic content, and quality. Malts and grains are combined in various ways: American whiskey is distilled from a fermented mash of cereal grain. It must have the taste, aroma, and other characteristics commonly attributed to whiskey. Some types of whiskey listed in the United States federal regulations are: These types of American whiskey must be distilled to no more than 80% alcohol by volume, and barrelled at no more than 125 proof. Only water may be added to the final product; the addition of colouring or flavouring is prohibited. These whiskeys


title: Whisky content: must be aged in new charred-oak containers, except for corn whiskey which does not have to be aged. If it is aged, it must be in uncharred oak barrels or in used barrels. Corn whiskey is usually unaged and sold as a legal version of moonshine. If one of these whiskey types reaches two years aging or beyond, it is additionally designated as "straight", e.g., "straight rye whiskey". A whiskey that fulfils all above requirements but derives from less than 51% of any one specific grain can be called simply a "straight whiskey" without naming a grain. US regulations recognize


title: Whisky content: other whiskey categories, including: Another important labelling in the marketplace is Tennessee whiskey, of which Jack Daniel's, George Dickel, Collier and McKeel, and Benjamin Prichard's are the only brands currently bottled. The main difference defining a Tennessee whiskey is its use of the Lincoln County Process, which involves filtration of the whiskey through charcoal. The rest of the distillation process is identical to bourbon whiskey. Whiskey sold as "Tennessee whiskey" is defined as bourbon under NAFTA and at least one other international trade agreement, and is similarly required to meet the legal definition of bourbon under Canadian law. Australian whiskies


title: Whisky content: have won global whisky awards and medals, including the World Whiskies Awards and Jim Murray's Whisky Bible "Liquid Gold Awards". By Canadian law, Canadian whiskies must be produced and aged in Canada, be distilled from a fermented mash of cereal grain, be aged in wood barrels with a capacity limit of for not less than three years, and "possess the aroma, taste and character generally attributed to Canadian whisky". The terms "Canadian Whisky", "Rye Whisky", and "Canadian Rye Whisky" are legally indistinguishable in Canada and do not require any specific grain in their production and are often blends of two


title: Whisky content: or more grains. Canadian whiskies may contain caramel and flavouring in addition to the distilled mash spirits, and there is no maximum limit on the alcohol level of the distillation. To be exported under one of the "Canadian Whisky" designations, a whisky cannot contain more than 9.09% imported spirits. Canadian whiskies are available throughout the world and are a culturally significant export. Well known brands include Crown Royal, Canadian Club, Seagram's, and Wiser's among others. The historic popularity of Canadian whisky in the United States is partly a result of rum runners illegally importing it into the country during the


title: Whisky content: period of American Prohibition. Denmark began producing whisky early in 1974. The first Danish single malt to go on sale was Lille Gadegård from Bornholm, in 2005. Lille Gadegård is a winery as well, and uses its own wine casks to mature whisky. The second Danish distilled single malt whisky for sale was Edition No.1 from the Braunstein microbrewery and distillery. It was distilled in 2007, using water from the Greenlandic ice sheet, and entered the market in March 2010. Another distillery is Stauning Whisky, based in Jutland. There are currently at least six distilleries producing English whisky. Though England