title: Boat

text: After "Homo erectus" possibly used watercraft more than a million years ago to cross straits between landmasses, boats have served as transportation far into pre-historic times. Circumstantial evidence, such as the early settlement of Australia over 40,000 years ago, findings in Crete dated 130,000 years ago and in Flores dated to 900,000 years ago, suggest that boats have been used since pre-historic times. The earliest boats are thought to have been dugouts, and the oldest boats found by archaeological excavation date from around 7,000 to 10,000 years ago. The oldest recovered boat in the world, the Pesse canoe, found in the Netherlands, is a dugout made from the hollowed tree trunk of a "Pinus sylvestris" that was constructed somewhere between 8200 and 7600 BC. This canoe is exhibited in the Drents Museum in Assen, Netherlands. Other very old dugout boats have also been recovered. Rafts have operated for at least 8,000 years. A 7,000-year-old seagoing reed boat has been found at site H3 in Kuwait. Boats were used between 4000 and 3000 BC in Sumer, where a 4000-year old boat has been excavated at Uruk, ancient Egypt, and in the Indian Ocean.


title: Boat

text: Boats played an important role in the commerce between the Indus Valley civilization and Mesopotamia. Evidence of varying models of boats has also been discovered at various Indus Valley archaeological sites. Uru craft originate in Beypore, a village in south Calicut, Kerala, in southwestern India. This type of mammoth wooden ship was constructed solely of teak, with a transport capacity of 400 tonnes. The ancient Arabs and Greeks used such boats as trading vessels.


title: Boat

text: The historians Herodotus, Pliny the Elder and Strabo record the use of boats for commerce, travel, and military purposes.


title: Boat

text: A number of large vessels are usually referred to as boats. Submarines are a prime example. Other types of large vessels which are traditionally called boats include Great Lakes freighters, riverboats, and ferryboats. Though large enough to carry their own boats and heavy cargoes, these vessels are designed for operation on inland or protected coastal waters.


title: Boat

text: The hull is the main, and in some cases only, structural component of a boat. It provides both capacity and buoyancy. The keel is a boat's "backbone", a lengthwise structural member to which the perpendicular frames are fixed. On some boats a deck covers the hull, in part or whole. While a ship often has several decks, a boat is unlikely to have more than one. Above the deck are often lifelines connected to stanchions, bulwarks perhaps topped by gunnels, or some combination of the two. A cabin may protrude above the deck forward, aft, along the centerline, or covering much of the length of the boat. Vertical structures dividing the internal spaces are known as bulkheads.


title: Boat

text: The forward end of a boat is called the bow, the aft end the stern. Facing forward the right side is referred to as starboard and the left side as port.


title: Boat

text: Until the mid-19th century most boats were made of natural materials, primarily wood, although reed, bark and animal skins were also used. Early boats include the bound-reed style of boat seen in Ancient Egypt, the birch bark canoe, the animal hide-covered kayak and coracle and the dugout canoe made from a single log.


title: Boat

text: By the mid-19th century, many boats had been built with iron or steel frames but still planked in wood. In 1855 ferro-cement boat construction was patented by the French, who coined the name "ferciment". This is a system by which a steel or iron wire framework is built in the shape of a boat's hull and covered over with cement. Reinforced with bulkheads and other internal structure it is strong but heavy, easily repaired, and, if sealed properly, will not leak or corrode.


title: Boat

text: As the forests of Britain and Europe continued to be over-harvested to supply the keels of larger wooden boats, and the Bessemer process (patented in 1855) cheapened the cost of steel, steel ships and boats began to be more common. By the 1930s boats built entirely of steel from frames to plating were seen replacing wooden boats in many industrial uses and fishing fleets. Private recreational boats of steel remain uncommon. In 1895 WH Mullins produced steel boats of galvanized iron and by 1930 became the world's largest producer of pleasure boats.


title: Boat

text: Mullins also offered boats in aluminum from 1895 through 1899 and once again in the 1920s, but it wasn't until the mid-20th century that aluminium gained widespread popularity. Though much more expensive than steel, aluminum alloys exist that do not corrode in salt water, allowing a similar load carrying capacity to steel at much less weight.


title: Boat

text: Around the mid-1960s, boats made of fiberglass (aka "glassfibre") became popular, especially for recreational boats. Fiberglass is also known as "GRP" (glass-reinforced plastic) in the UK, and "FRP" (for fiber-reinforced plastic) in the US. Fiberglass boats are strong, and do not rust, corrode, or rot. Instead, they are susceptible to structural degradation from sunlight and extremes in temperature over their lifespan. Fiberglass structures can be made stiffer with sandwich panels, where the fiberglass encloses a lightweight core such as balsa or foam.


title: Boat

text: Cold molding is a modern construction method, using wood as the structural component. In one cold molding process, very thin strips of wood are layered over a form. Each layer is coated with resin, followed by another directionally alternating layer laid on top. Subsequent layers may be stapled or otherwise mechanically fastened to the previous, or weighted or vacuum bagged to provide compression and stabilization until the resin sets. An alternative process uses thin sheets of plywood shaped over a disposable male mold, and coated with epoxy.


title: Boat

text: A boat displaces its weight in water, regardless whether it is made of wood, steel, fiberglass, or even concrete. If weight is added to the boat, the volume of the hull drawn below the waterline will increase to keep the balance above and below the surface equal. Boats have a natural or designed level of buoyancy. Exceeding it will cause the boat first to ride lower in the water, second to take on water more readily than when properly loaded, and ultimately, if overloaded by any combination of structure, cargo, and water, sink.


title: Boat

text: As commercial vessels must be correctly loaded to be safe, and as the sea becomes less buoyant in brackish areas such as the Baltic, the Plimsoll line was introduced to prevent overloading.


title: Boat

text: Since 1998 all new leisure boats and barges built in Europe between 2.5m and 24m must comply with the EU's Recreational Craft Directive (RCD). The Directive establishes four categories that permit the allowable wind and wave conditions for vessels in each class:


title: Boat

text: Europe is the main producer of recreational boats (the second production in the world is located in Poland). European brands are known all over the world - in fact, these are the brands that created RCD and set the standard for shipyards around the world.


title: Snickers

text: Snickers is a chocolate bar made by the American company Mars, Incorporated, consisting of nougat topped with caramel and peanuts that is encased in milk chocolate. The annual global sales of Snickers was over $3 billion .


title: Snickers

text: In the United Kingdom, Snickers was sold under the brand name Marathon until 1990. A Marathon retro edition was sold exclusively at Morrisons for three months in 2020.


title: Snickers

text: In 1930, Mars introduced Snickers, named after the favorite horse of the Mars family. The Snickers chocolate bar consists of nougat, peanuts, and caramel with a chocolate coating. The bar was marketed under the name "Marathon" in the UK and Ireland until 1990, when Mars decided to align the UK product with the global Snickers name (Mars had marketed and discontinued an unrelated bar named Marathon in the United States during the 1970s which was similar to the UK's Curly Wurly). There are also several other Snickers products such as Snickers mini, dark chocolate, ice cream bars, Snickers with almonds, Snickers with hazelnuts, Snickers with pecans, Snickers peanut butter bars, Snickers protein and Snickers with Extra Caramel, as well as espresso, fiery, and sweet & salty versions.


title: Snickers

text: The early (1939) ingredients list includes white sugar, sweet milk chocolate, corn syrup, peanuts, milk condensed with sugar, coconut oil, malted milk, whites of eggs and salt. By 2019, the ingredients for the original bar had been refined to milk chocolate (sugar, cocoa butter, chocolate, skim milk, lactose, milkfat, soy lecithin, artificial flavor), peanuts, corn syrup, sugar, palm oil, skim milk, lactose, salt, egg whites, artificial flavor.


title: Snickers

text: The USDA lists the caloric value of a 2-ounce (57 gram) Snickers bar as . As of 2018, the United Kingdom bar has a weight of , with 245 kcal, and the Canadian bar with 250 kcal.


title: Snickers

text: Over the years, the bar weight has decreased: Before 2009, in the UK a single Snickers bar had a weight of . This weight was subsequently reduced to in 2009, and to in 2013. In the United States the listed weight in 2018 was 52.7 g. In Australia, Snickers bars were originally made locally and weighed , however in the late 2010s production moved to China and the bars were shrunk to . In 2022, production returned to Australia and bars further reduced in weight to .


title: Snickers

text: Containing approximately per bar, deep fried chocolate bars (including Snickers and Mars bars) became a specialty in fish and chips shops in Scotland in 1995, and in the early 2000s, became popular at American state fairs.


title: Snickers

text: In 2006, the British Food Commission highlighted celebrity chef Antony Worrall Thompson's "Snickers pie", which contained five Snickers bars among other ingredients, suggesting it was one of the unhealthiest desserts ever; one slice providing "over from sugar and fat alone", more than half a day's requirement for an average adult. The pie had featured on his BBC Saturday programme some two years earlier and the chef described it as an occasional treat only.


title: Snickers

text: In 1980, Snickers (and Marathon) ran ads which featured a variety of everyday people discussing why they like Snickers. The ads featured a jingle that said "It's so satisfying" and had the classic hand that would open and close showing a handful of peanuts converting to a Snickers bar. "Packed with peanuts, Snickers really satisfies" was shown in the commercials.


title: Snickers

text: Mars paid $5 million to have Snickers and M&M's named the "official snack" of the 1984 Summer Olympics, outraging nutritionists. Sports promotions in international games continued to be a prominent marketing tool for Mars, that would keep Snickers as an international brand while also selling local bars in some markets.


title: Snickers

text: Beginning in 1995, Snickers ran ads which featured someone making a self-inflicted mistake, with the voice-over saying "Not going anywhere for a while? Grab a Snickers!" The tag line at the end of each ad proclaimed, "Hungry? Why Wait?"


title: Snickers

text: One such ad had a player for a fictional American football team showing off his new tattoo of the team's logo on his back to his teammates. He then shows it to his head coach who, after complimenting the tattoo, immediately tells him that he's been traded to Miami. The player then goes to have his old team's logo replaced with the new team's logo.


title: Snickers

text: Some of the ads were done in conjunction with the National Football League, with whom Snickers had a sponsorship deal at the time. One ad featured a member of the grounds crew at Arrowhead Stadium painting the field for an upcoming Kansas City Chiefs game in hot, late-summer weather. After finishing one of the end zones, and visibly exhausted, one of the Chiefs players walks up to him and says the field looks great, "but who are the Chefs?", showing that despite all the hard work the painter accidentally omitted the "i" in Chiefs. Another had Marv Levy in the Buffalo Bills locker room lecturing his team that "no one's going anywhere" until the Bills figure out how to actually win a Super Bowl.


title: Snickers

text: In 2007, Snickers launched a campaign which featured Henry VIII and a Viking among others who attend the "Snickers Feast". It consisted of various commercials of the gang and their adventures on the feast.


title: Snickers

text: On February 4, 2007, during Super Bowl XLI, Snickers commercials aired. This resulted in complaints by gay and lesbian groups against the maker of the candy bar, Masterfoods USA of Hackettstown, New Jersey, a division of Mars, Incorporated. The commercial showed a pair of auto mechanics accidentally kissing while sharing a Snickers bar. After quickly pulling away, one mechanic sheepishly says, "I think we just accidentally kissed.", and another mechanic frantically exclaims, "Quick! Do something manly!" and in three of the four versions, they do so mostly in the form of injury, including tearing out chest hair, striking each other with a very large pipe wrench, and drinking motor oil and windshield washer fluid. In the fourth version, however, a third mechanic shows up and asks "Is there room for three in this Love Boat?"


title: Snickers

text: Complaints were lodged against Masterfoods that the ads were homophobic. Human Rights Campaign president Joe Solmonese is quoted as saying, "This type of jeering from professional sports figures at the sight of two men kissing fuels the kind of anti-gay bullying that haunts countless gay and lesbian school children on playgrounds all across the country."


title: Snickers

text: Gay and Lesbian Alliance Against Defamation (GLAAD) president Neil Giuliano said "That Snickers, Mars and the NFL would promote and endorse this kind of prejudice is simply inexcusable." Masterfoods has since pulled the ads and the website.


title: Snickers

text: In 2006, Mr. T starred in a Snickers advertisement in the UK where he rides up in an army tank and shouts abuse at a football player who appears to be faking an injury, threatening to introduce him to his friend Pain. Another advertisement featured Mr. T launching bars at a swimmer who appeared to refuse to get in a swimming pool because of the cold temperature of the water. In 2008, a European Snickers commercial in which Mr. T uses a Jeep-mounted Minigun to fire Snickers bars at a speedwalker for being a "disgrace to the man race" was pulled after complaints from a US pressure group that the advertisement was homophobic. These advertisements usually ended with Mr. T saying "Snickers: Get Some Nuts!"


title: Snickers

text: In NASCAR racing, Snickers (and the rest of the Mars affiliated brands) sponsor Kyle Busch's #18 Toyota for Joe Gibbs Racing. Prior to that the brand served as a primary sponsor for Ricky Rudd's #88 Robert Yates Racing Ford as well as an associate sponsor for the team's #38 car driven first by Elliott Sadler and then by David Gilliland, and an associate sponsor for the MB2 Motorsports #36 Pontiac driven by Derrike Cope, Ernie Irvan, Ken Schrader, and others. In 1990, Bobby Hillin drove for Stavola Brothers Racing in the #8 Snickers Buick, marking the candy's first appearance as a sponsor; it had since been driven by Rick Wilson and Dick Trickle. Mars announced that at the conclusion of the 2022 NASCAR Cup Series season, they will pull their sponsorship from not only Joe Gibbs Racing, but NASCAR entirely.


title: Snickers

text: Snickers was the Official Sponsor of the FIFA World Cup from 1990 until 1998 editions and the UEFA European Championship from 1996 until 2000.


title: Snickers

text: In 2010, a new advertising campaign was launched, usually based around people turning into different people (usually celebrities) as a result of hunger (taking the new campaign's name "You're Not You When You're Hungry" quite literally). The tagline varied depending on the commercial's location or what variety the commercial is showing. The American adverts initially ended with the tagline "Snickers Satisfies". Steve Burns, best known as the first host of the children’s show "Blue’s Clues" has done the voice of the announcer. BBDO New York said this campaign made Snickers the number one candy bar, up from seventh. In 2020, "USA Today"'s Ad Meter named it the best Super Bowl campaign of the past 25 years.


title: Snickers

text: In 2010, Betty White and Abe Vigoda appeared in the first Snickers commercial in this campaign, playing American football. The commercial was ranked by ADBOWL as the best advertisement of the year. This commercial was also briefly spoofed in an episode of "SportsNation" on ESPN2 with Michelle Beadle playing the role instead of Betty White in 2011. Later that year, Snickers commercials featured singers Aretha Franklin and Liza Minnelli, and comedians Richard Lewis and Roseanne Barr. A 2011 commercial featured actors Joe Pesci and Don Rickles.


title: Snickers

text: In Latin America, the slogan was the same as in the UK version, except that men doing extreme sports turning into the Mexican singer Anahí as a result of hunger. Brazilian versions of the ad featured actresses Betty Faria and Cláudia Raia.


title: Snickers

text: In 2013, Robin Williams and Bobcat Goldthwait appeared in a Snickers football commercial. Russian duo t.A.T.u. appeared in a Japanese Snickers commercial as themselves throwing a tantrum in a baseball game before eating the chocolate reverts them into normal baseball players. In March 2014, a commercial featuring Godzilla was released to promote the 2014 Godzilla film. In the commercial, Godzilla is shown hanging out with humans on the beach, riding dirt bikes, and water skiing; he only begins rampaging once he is hungry. After being fed a Snickers bar, he resumes having fun with the humans.


title: Snickers

text: In February 2015, Snickers' Super Bowl XLIX commercial featured a parody of a scene from an episode of "The Brady Bunch" entitled "The Subject Was Noses." In the commercial, Carol and Mike try to calm down a very angry Machete (played by Danny Trejo). When the parents give Machete a Snickers bar, he reverts into Marcia before an irate Jan (played by Steve Buscemi) rants upstairs and walks away. In a second commercial set earlier, Marcia (as Machete) angrily brushes her hair while yelling through her door.


title: Snickers

text: In 2016, for Super Bowl 50, another Snickers commercial was made, featuring Willem Dafoe (as Marilyn Monroe) and Eugene Levy, where Willem Dafoe complains about filming the iconic "subway grate" scene in "The Seven Year Itch". After being given a Snickers, he turns into Marilyn and goes ahead with the scene, with Levy operating the fan below, commenting that the scene will not make the movie's final cut, that nobody would want to see it.


title: Snickers

text: In 2018, Brazil World Cup winner Ronaldo is seen celebrating a goal for Argentina. When he notices the confused faces around him, he eats a Snickers and returns to normal.


title: Snickers

text: The UK version of the campaign usually used British celebrities and, up until 2018, retained the slogan from the Mr. T. era. In the initial advertisement, Joan Collins and Stephanie Beacham featured as locker room footballers who had turned into them due to being hungry. In 2014, Rowan Atkinson as Mr. Bean returned on television by appearing on several UK Snickers commercials and cinema spots, in place of a martial arts master who had turned into him as a result of hunger. Later, in 2018, Elton John appeared in a new advertisement where he turns into African American rapper Boogie after he eats a Snickers; the latter had turned into the former due to hunger (the slogan appeared on a turntable in this advertisement).


title: Snickers

text: This campaign was revived in 2022 in the UK under a slightly different form and new slogan "You're Unfiltered When You're Hungry" while using the initial American "Satisfies" slogan.


title: Snickers

text: In 2020, a new, albeit short-lived, campaign was introduced that focused on people doing things that contradicted what they think they are doing, such as a man crawling along rocky ground when he thought he was climbing a rock face, the new slogan above indicating it to be the result of hunger-induced confusion.


title: Snickers

text: Snickers has been an official sponsor of WWE's WrestleMania events, including WrestleMania 2000, 22, 32, 33, 34, 35, 36, 37 and 38, while its Cruncher variant sponsored WrestleMania X-Seven, XIX, XX and 21. Since then, Snickers has sponsored superstars such as Enzo Amore and Big Cass with their signature term, SAWFT, which is labelled at the back of the chocolate bar.


title: Snickers

text: Since 2011, Snickers has been the official sponsor of Six Flags' annual Fright Fest event at its theme parks.


title: Snickers

text: In March 2020, the official Snickers Twitter account caused controversy when it posted a tweet comparing the Welsh language and Welsh place names to someone "sitting on a keyboard". The offending tweet was deleted and an apology was posted soon after.


title: Snickers

text: A replacement for the king size Snickers bar was launched in the UK in 2004, and designed to conform to the September 2004 Food and Drink Federation (FDF) "Manifesto for Food and Health". Part of the FDF manifesto was seven pledges of action to encourage the food and drink industry to be more health conscious. Reducing portion size, clearer food labels, and reduction of the levels of fat, sugar, and salt were among the FDF pledges. Mars Incorporated pledged to phase out their king-size bars in 2005 and replace them with shareable bars. A Mars spokesman said: "Our king-size bars that come in one portion will be changed so they are shareable or can be consumed on more than one occasion. The name king-size will be phased out."


title: Snickers

text: These were eventually replaced by the 'Duo' - a double bar pack. Though this change to Duos reduced the weight from , the price remained the same. The packaging has step-by-step picture instructions of how to open a Duo into two bars, in four simple actions. As Mars stated fulfillment of their promise, the Duo format was met with criticism by the National Obesity Forum and National Consumer Council.


title: Snickers

text: In December 2000, tens of thousands of Snickers and Mars Bars were removed from New South Wales store shelves due to a series of threatening letters which resulted in fears that the chocolate bars had been poisoned. Mars received letters from an unidentified individual indicating that they planned to plant poisoned chocolate bars on store shelves. The last letter sent included a Snickers bar contaminated with a substance which was later identified as rat poison. The letters claimed that there were seven additional chocolate bars which had been tampered with and which were for sale to the public. As a precautionary measure, Mars issued a massive recall. Mars said that there had been no demand for money and complaints directed to an unidentified third party.


title: Snickers

text: In April 2022, a Twitter user satirically claimed in a viral tweet that Snickers was removing the "dick vein" design from the top of the candy bar, prompting a backlash from unwitting Snickers fans. Due to the volume of response, Snickers clarified in its own viral tweet that the "veins remain".


title: Headphones

text: Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earspeakers, earphones or, colloquially, cans. Circumaural ('around the ear') and supra-aural ('over the ear') headphones use a band over the top of the head to hold the speakers in place. Another type, known as earbuds or earpieces consist of individual units that plug into the user's ear canal. A third type are bone conduction headphones, which typically wrap around the back of the head and rest in front of the ear canal, leaving the ear canal open. In the context of telecommunication, a headset is a combination of headphone and microphone.


title: Headphones

text: Headphones connect to a signal source such as an audio amplifier, radio, CD player, portable media player, mobile phone, video game console, or electronic musical instrument, either directly using a cord, or using wireless technology such as Bluetooth, DECT or FM radio. The first headphones were developed in the late 19th century for use by telephone operators, to keep their hands free. Initially the audio quality was mediocre and a step forward was the invention of high fidelity headphones.


title: Headphones

text: Headphones exhibit a range of different audio reproduction quality capabilities. Headsets designed for telephone use typically cannot reproduce sound with the high fidelity of expensive units designed for music listening by audiophiles. Headphones that use cables typically have either a 1/4 inch (6.35mm) or 1/8 inch (3.5mm) phone jack for plugging the headphones into the audio source. Some stereo earbuds are wireless, using Bluetooth connectivity to transmit the audio signal by radio waves from source devices like cellphones and digital players. As a result of the Walkman effect, beginning in the 1980s, headphones started to be used in public places such as sidewalks, grocery stores, and public transit. Headphones are also used by people in various professional contexts, such as audio engineers mixing sound for live concerts or sound recordings and DJs, who use headphones to cue up the next song without the audience hearing, aircraft pilots and call center employees. The latter two types of employees use headphones with an integrated microphone.


title: Headphones

text: Headphones grew out of the need to free up a person's hands when operating a telephone. There were several iterative products that were predecessors to the "hands-free" headphones. By the 1890s the first device that is unmistakably a headphone was made by a British company called Electrophone, which created a system allowing their customers to connect into live feeds of performances at theaters and opera houses across London. Subscribers to the service could listen to the performance through a pair of massive earphones that connected below the chin, held by a long rod.


title: Headphones

text: French engineer Ernest Mercadier patented a set of in-ear headphones in 1891, Mercadier was awarded U.S. Patent No. 454,138 for “improvements in telephone-receivers…which shall be light enough to be carried while in use on the head of the operator.”


title: Headphones

text: Nathaniel Baldwin of Utah in 1910 invented a prototype telephone headset due to his inability to hear sermons during Sunday service. He offered it for testing to the US Navy, which promptly ordered 100 from Baldwin. Wireless Specialty Apparatus Co., in partnership with Baldwin Radio Company, set up a manufacturing facility in Utah to fulfill orders. His innovations were the basis of “sound-powered” telephones or phones that required no electricity, which were used during World War II.


title: Headphones

text: Headphones originated from the telephone receiver earpiece, and were the only way to listen to electrical audio signals before amplifiers were developed.


title: Headphones

text: These early headphones used moving iron drivers, with either single-ended or balanced armatures. The common single-ended type used voice coils wound around the poles of a permanent magnet, which were positioned close to a flexible steel diaphragm. The audio current through the coils varied the magnetic field of the magnet, exerting a varying force on the diaphragm, causing it to vibrate, creating sound waves. The requirement for high sensitivity meant that no damping was used, so the frequency response of the diaphragm had large peaks due to resonance, resulting in poor sound quality. These early models lacked padding, and were often uncomfortable to wear for long periods. Their impedance varied; headphones used in telegraph and telephone work had an impedance of 75 ohms. Those used with early wireless radio had more turns of finer wire to increase sensitivity. Impedance of 1,000 to 2,000 ohms was common, which suited both crystal sets and triode receivers. Some very sensitive headphones, such as those manufactured by Brandes around 1919, were commonly used for early radio work.


title: Headphones

text: In early powered radios, the headphone was part of the vacuum tube's plate circuit and carried dangerous voltages. It was normally connected directly to the positive high voltage battery terminal, and the other battery terminal was securely grounded. The use of bare electrical connections meant that users could be shocked if they touched the bare headphone connections while adjusting an uncomfortable headset.


title: Headphones

text: In 1958, John C. Koss, an audiophile and jazz musician from Milwaukee, produced the first stereo headphones.


title: Headphones

text: Smaller earbud type earpieces, which plugged into the user's ear canal, were first developed for hearing aids. They became widely used with transistor radios, which commercially appeared in 1954 with the introduction of the Regency TR-1. The most popular audio device in history, the transistor radio changed listening habits, allowing people to listen to radio anywhere. The earbud uses either a moving iron driver or a piezoelectric crystal to produce sound. The 3.5 mm radio and phone connector, which is the most commonly used in portable application today, has been used at least since the Sony EFM-117J transistor radio, which was released in 1964. Its popularity was reinforced with its use on the Walkman portable tape player in 1979.


title: Headphones

text: Headphones may be used with stationary CD and DVD players, home theater, personal computers, or portable devices (e.g., digital audio player/MP3 player, mobile phone), as long as these devices are equipped with a headphone jack. Cordless headphones are not connected to their source by a cable. Instead, they receive a radio or infrared signal encoded using a radio or infrared transmission link, such as FM, Bluetooth or Wi-Fi. These are battery-powered receiver systems, of which the headphone is only a component. Cordless headphones are used with events such as a Silent disco or Silent Gig.


title: Headphones

text: In the professional audio sector, headphones are used in live situations by disc jockeys with a DJ mixer, and sound engineers for monitoring signal sources. In radio studios, DJs use a pair of headphones when talking to the microphone while the speakers are turned off to eliminate acoustic feedback while monitoring their own voice. In studio recordings, musicians and singers use headphones to play or sing along to a backing track or band. In military applications, audio signals of many varieties are monitored using headphones.


title: Headphones

text: Wired headphones are attached to an audio source by a cable. The most common connectors are 6.35 mm (inch) and 3.5 mm phone connectors. The larger 6.35 mm connector is more common on fixed location home or professional equipment. The 3.5 mm connector remains the most widely used connector for portable application today. Adapters are available for converting between 6.35 mm and 3.5 mm devices.


title: Headphones

text: As active component, wireless headphones tend to be costlier due to the necessity for internal hardware such as a battery, a charging controller, a speaker driver, and a wireless transceiver, whereas wired headphones are a passive component, outsourcing speaker driving to the audio source.


title: Headphones

text: Wired headphones may be equipped with a non-detachable cable or a detachable auxiliary male-to-male plug, as well as some with two ports to allow connecting another wired headphone in a parallel circuit, which splits the audio signal to share with another participant, but can also be used to hear audio from two inputs simultaneously. An external audio splitter can retrofit this ability.


title: Headphones

text: Various types of specially designed headphones or earphones are also used to evaluate the status of the auditory system in the field of audiology for establishing hearing thresholds, medically diagnosing hearing loss, identifying other hearing related disease, and monitoring hearing status in occupational hearing conservation programs. Specific models of headphones have been adopted as the standard due to the ease of calibration and ability to compare results between testing facilities.


title: Headphones

text: Supra-aural style headphones are historically the most commonly used in audiology as they are the easiest to calibrate and were considered the standard for many years. Commonly used models are the Telephonics Dynamic Headphone (TDH) 39, TDH-49, and TDH-50. In-the-ear or insert style earphones are used more commonly today as they provide higher levels of interaural attenuation, introduce less variability when testing 6,000 and 8,000 Hz, and avoid testing issues resulting from collapsed ear canals. A commonly used model of insert earphone is the Etymotic Research ER-3A. Circum-aural earphones are also used to establish hearing thresholds in the extended high frequency range (8,000 Hz to 20,000 kHz). Along with Etymotic Research ER-2A insert earphones, the Sennheiser HDA300 and Koss HV/1A circum-aural earphones are the only models that have reference equivalent threshold sound pressure level values for the extended high frequency range as described by ANSI standards.


title: Headphones

text: Audiometers and headphones must be calibrated together. During the calibration process, the output signal from the audiometer to the headphones is measured with a sound level meter to ensure that the signal is accurate to the reading on the audiometer for sound pressure level and frequency. Calibration is done with the earphones in an acoustic coupler that is intended to mimic the transfer function of the outer ear. Because specific headphones are used in the initial audiometer calibration process, they cannot be replaced with any other set of headphones, even from the same make and model.


title: Headphones

text: Electrical characteristics of dynamic loudspeakers may be readily applied to headphones, because most headphones are small dynamic loudspeakers.


title: Headphones

text: Headphones are available with high or low impedance (typically measured at 1 kHz). Low-impedance headphones are in the range 16 to 32 ohms and high-impedance headphones are about 100-600 ohms. As the impedance of a pair of headphones increases, more voltage (at a given current) is required to drive it, and the loudness of the headphones for a given voltage decreases. In recent years, impedance of newer headphones has generally decreased to accommodate lower voltages available on battery powered CMOS-based portable electronics. This has resulted in headphones that can be more efficiently driven by battery-powered electronics. Consequently, newer amplifiers are based on designs with relatively low output impedance.


title: Headphones

text: The impedance of headphones is of concern because of the output limitations of amplifiers. A modern pair of headphones is driven by an amplifier, with lower impedance headphones presenting a larger load. Amplifiers are not ideal; they also have some output impedance that limits the amount of power they can provide. To ensure an even frequency response, adequate damping factor, and undistorted sound, an amplifier should have an output impedance less than 1/8 that of the headphones it is driving (and ideally, as low as possible). If output impedance is large compared to the impedance of the headphones, significantly higher distortion is present. Therefore, lower impedance headphones tend to be louder and more efficient, but also demand a more capable amplifier. Higher impedance headphones are more tolerant of amplifier limitations, but produce less volume for a given output level.


title: Headphones

text: Historically, many headphones had relatively high impedance, often over 500 ohms so they could operate well with high-impedance tube amplifiers. In contrast, modern transistor amplifiers can have very low output impedance, enabling lower-impedance headphones. Unfortunately, this means that older audio amplifiers or stereos often produce poor-quality output on some modern, low-impedance headphones. In this case, an external headphone amplifier may be beneficial.


title: Headphones

text: Sensitivity is a measure of how effectively an earpiece converts an incoming electrical signal into an audible sound. It thus indicates how loud the headphones are for a given electrical drive level. It can be measured in decibels of sound pressure level per milliwatt (dB (SPL)/mW) or decibels of sound pressure level per volt (dB (SPL) / V). Unfortunately, both definitions are widely used, often interchangeably. As the output voltage (but not power) of a headphone amplifier is essentially constant for most common headphones, dB/mW is often more useful if converted into dB/V using Ohm's law:


title: Headphones

text: Alternatively, online calculators can be used. Once the sensitivity per volt is known, the maximum volume for a pair of headphones can be easily calculated from the maximum amplifier output voltage. For example, for a headphone with a sensitivity of 100 dB (SPL)/V, an amplifier with an output of 1 root mean square (RMS) voltage produces a maximum volume of 100 dB.


title: Headphones

text: Pairing high-sensitivity headphones with power amplifiers can produce dangerously high volumes and damage headphones. The maximum sound pressure level is a matter of preference, with some sources recommending no higher than 110 to 120 dB. In contrast, the American Occupational Safety and Health Administration recommends an average SPL of no more than 85 dB(A) to avoid long-term hearing loss, while the European Union standard EN 50332-1:2013 recommends that volumes above 85 dB(A) include a warning, with an absolute maximum volume (defined using 40–4,000 Hz noise) of no more than 100 dB to avoid accidental hearing damage. Using this standard, headphones with sensitivities of 90, 100 and 110 dB (SPL)/V should be driven by an amplifier capable of no more than 3.162, 1.0 and 0.3162 RMS volts at maximum volume setting, respectively to reduce the risk of hearing damage.


title: Headphones

text: The sensitivity of headphones is usually between about 80 and 125 dB/mW and usually measured at 1 kHz.


title: Headphones

text: Headphone size can affect the balance between fidelity and portability. Generally, headphone form factors can be divided into four separate categories: "circumaural (over-ear)", "supra-aural (on-ear)", "earbud" and "in-ear".


title: Headphones

text: True wireless earbuds have no cord to keep each bud connected to each other. They rely on wireless technology such as Bluetooth to transmit audio from a hardware device.


title: Headphones

text: Circumaural headphones (sometimes called full size headphones or over-ear headphones) have circular or ellipsoid earpads that encompass the ears. Because these headphones completely surround the ear, circumaural headphones can be designed to fully seal against the head to attenuate external noise. Because of their size, circumaural headphones can be heavy and there are some sets that weigh over . Ergonomic headband and earpad design is required to reduce discomfort resulting from weight. These are commonly used by drummers in recording.


title: Headphones

text: Supra-aural headphones or on-ear headphones have pads that press against the ears, rather than around them. They were commonly bundled with personal stereos during the 1980s. This type of headphone generally tends to be smaller and lighter than circumaural headphones, resulting in less attenuation of outside noise. Supra-aural headphones can also lead to discomfort due to the pressure on the ear as compared to circumaural headphones that sit around the ear. Comfort may vary due to the earcup material.


title: Headphones

text: Earphones are very small headphones that are fitted directly in the outer ear, facing but not inserted in the ear canal. Earphones are portable and convenient, but many people consider them uncomfortable. They provide hardly any acoustic isolation and leave room for ambient noise to seep in; users may turn up the volume dangerously high to compensate, at the risk of causing hearing loss. On the other hand, they let the user be better aware of their surroundings. Since the early days of the transistor radio, earphones have commonly been bundled with personal music devices. They are sold at times with foam or rubber pads for comfort. (The use of the term "earbuds", which has been around since at least 1984, did not hit its peak until after 2001, with the success of Apple's MP3 player.)


title: Headphones

text: In-ear headphones, also known as in-ear monitors (IEMs) or canalphones, are small headphones with similar portability to earbuds that are inserted in the ear canal itself. IEMs are higher-quality in-ear headphones and are used by audio engineers and musicians as well as audiophiles.


title: Headphones

text: The outer shells of in-ear headphones are made up of a variety of materials, such as plastic, aluminum, ceramic and other metal alloys. Because in-ear headphones engage the ear canal, they can be prone to sliding out, and they block out much environmental noise. Lack of sound from the environment can be a problem when sound is a necessary cue for safety or other reasons, as when walking, driving, or riding near or in vehicular traffic. Some in-ear headphones utilize built-in microphones to allow some outside sound to be heard when desired.


title: Headphones

text: Generic or custom-fitting ear canal plugs are made from silicone rubber, elastomer, or foam. Such plugs in lower-end devices may be interchangeable, which increases the risk of them falling off and getting lodged in the ear canal. Custom in-ear headphones use castings of the ear canal to create custom-molded plugs that provide added comfort and noise isolation.


title: Headphones

text: Open-back headphones have the back of the earcups open. This leaks more sound out of the headphone and also lets more ambient sounds into the headphone, but gives a more natural or speaker-like sound, due to including sounds from the environment.


title: Headphones

text: Semi-open headphones, have a design that can be considered as a compromise between open-back headphones and closed-back headphones. Some believe the term "semi-open" is purely there for marketing purposes. There is no exact definition for the term semi-open headphone. Where the open-back approach has hardly any measure to block sound at the outer side of the diaphragm and the closed-back approach really has a closed chamber at the outer side of the diaphragm, a semi-open headphone can have a chamber to partially block sound while letting some sound through via openings or vents.


title: Headphones

text: Closed-back (or sealed) styles have the back of the earcups closed. They usually block some of the ambient noise. Closed-back headphones usually can produce stronger low frequencies than open-back headphones.


title: Headphones

text: A headset is a headphone combined with a microphone. Headsets provide the equivalent functionality of a telephone handset with hands-free operation. Among applications for headsets, besides telephone use, are aviation, theatre or television studio intercom systems, and console or PC gaming. Headsets are made with either a single-earpiece (mono) or a double-earpiece (mono to both ears or stereo). The microphone arm of headsets is either an external microphone type where the microphone is held in front of the user's mouth, or a voicetube type where the microphone is housed in the earpiece and speech reaches it by means of a hollow tube.


title: Headphones

text: Telephone headsets connect to a fixed-line telephone system. A telephone headset functions by replacing the handset of a telephone. Headsets for standard corded telephones are fitted with a standard 4P4C commonly called an RJ-9 connector. Headsets are also available with 2.5 mm jack sockets for many DECT phones and other applications. Cordless bluetooth headsets are available, and often used with mobile telephones. Headsets are widely used for telephone-intensive jobs, in particular by call centre workers. They are also used by anyone wishing to hold telephone conversations with both hands free.


title: Headphones

text: For older models of telephones, the headset microphone impedance is different from that of the original handset, requiring a telephone amplifier for the telephone headset. A telephone amplifier provides basic pin-alignment similar to a telephone headset adaptor, but it also offers sound amplification for the microphone as well as the loudspeakers. Most models of telephone amplifiers offer volume control for loudspeaker as well as microphone, mute function and switching between headset and handset. Telephone amplifiers are powered by batteries or AC adaptors.


title: Headphones

text: Communication headsets are used for two-way communication and typically consist of a headphone and attached microphone. Such headsets are used in a variety of professions as aviation, military, sports, music, and many service-oriented sectors. They come in all shapes and sizes, depending on use, required noise attenuation, and fidelity of communication needed.


title: Headphones

text: Unwanted sound from the environment can be reduced by excluding sound from the ear by passive noise isolation, or, often in conjunction with isolation, by active noise cancellation.


title: Headphones

text: Passive noise isolation is essentially using the body of the earphone, either over or in the ear, as a passive earplug that simply blocks out sound. The headphone types that provide most attenuation are in-ear canal headphones and closed-back headphones, both circumaural and supra aural. Open-back and earbud headphones provide some passive noise isolation, but much less than the others. Typical closed-back headphones block 8 to 12 dB, and in-ears anywhere from 10 to 15 dB. Some models have been specifically designed for drummers to facilitate the drummer monitoring the recorded sound while reducing sound directly from the drums as much as possible. Such headphones claim to reduce ambient noise by around 25 dB.


title: Headphones

text: Active noise-cancelling headphones use a microphone, amplifier, and speaker to pick up, amplify, and play ambient noise in phase-reversed form; this to some extent cancels out unwanted noise from the environment without affecting the desired sound source, which is not picked up and reversed by the microphone. They require a power source, usually a battery, to drive their circuitry. Active noise cancelling headphones can attenuate ambient noise by 20 dB or more, but the active circuitry is mainly effective on constant sounds and at lower frequencies, rather than sharp sounds and voices. Some noise cancelling headphones are designed mainly to reduce low-frequency engine and travel noise in aircraft, trains, and automobiles, and are less effective in environments with other types of noise.


title: Headphones

text: The moving coil driver, more commonly referred to as a "dynamic" driver is the most common type used in headphones. It consists of a stationary magnet element affixed to the frame of the headphone, which sets up a static magnetic field. The magnet in headphones is typically composed of ferrite or neodymium. A voice coil, a light coil of wire, is suspended in the magnetic field of the magnet, attached to a diaphragm, typically fabricated from lightweight, high-stiffness-to-mass-ratio cellulose, polymer, carbon material, paper or the like. When the varying current of an audio signal is passed through the coil, it creates a varying magnetic field that reacts against the static magnetic field, exerting a varying force on the coil causing it and the attached diaphragm to vibrate. The vibrating diaphragm pushes on the air to produce sound waves.


title: Headphones

text: Electrostatic drivers consist of a thin, electrically charged diaphragm, typically a coated PET film membrane, suspended between two perforated metal plates (electrodes). The electrical sound signal is applied to the electrodes creating an electrical field; depending on the polarity of this field, the diaphragm is drawn towards one of the plates. Air is forced through the perforations; combined with a continuously changing electrical signal driving the membrane, a sound wave is generated. Electrostatic headphones are usually more expensive than moving-coil ones, and are comparatively uncommon. In addition, a special amplifier is required to amplify the signal to deflect the membrane, which often requires electrical potentials in the range of 100 to 1,000 volts.


title: Headphones

text: Due to the extremely thin and light diaphragm membrane, often only a few micrometers thick, and the complete absence of moving metalwork, the frequency response of electrostatic headphones usually extends well above the audible limit of approximately 20 kHz. The high-frequency response means that the low-midband distortion level is maintained to the top of the audible frequency band, which is generally not the case with moving coil drivers. Also, the frequency response peakiness regularly seen in the high-frequency region with moving coil drivers is absent. Well-designed electrostatic headphones can produce significantly better sound quality than other types.


title: Headphones

text: Electrostatic headphones require a voltage source generating 100 V to over 1 kV, and are on the user's head. Since the invention of insulators, there is no actual danger. They do not need to deliver significant electric current, which further limits the electrical hazard to the wearer in case of fault.


title: Headphones

text: An electret driver functions along the same electromechanical means as an electrostatic driver. However the electret driver has a permanent charge built into it, whereas electrostatics have the charge applied to the driver by an external generator. Electret and electrostatic headphones are relatively uncommon. Original electrets were also typically cheaper and lower in technical capability and fidelity than electrostatics. Patent applications from 2009 to 2013 have been approved that show by using different materials, i.e. a "Fluorinated cyclic olefin electret film", Frequency response chart readings can reach 50 kHz at 100db. When these new improved electrets are combined with a traditional dome headphone driver, headphones can be produced that are recognised by the Japan Audio Society as worthy of joining the Hi Res Audio program. US patents 8,559,660 B2. 7,732,547 B2.7,879,446 B2.7,498,699 B2.


title: Headphones

text: Planar magnetic (also known as orthodynamic) headphones use similar technology to electrostatic headphones, with some fundamental differences. They operate similarly to planar magnetic loudspeakers.


title: Headphones

text: A planar magnetic driver consists of a relatively large membrane that contains an embedded wire pattern. This membrane is suspended between two sets of permanent, oppositely aligned, magnets. A current passed through the wires embedded in the membrane produces a magnetic field that reacts with the field of the permanent magnets to induce movement in the membrane, which produces sound.


title: Headphones

text: A balanced armature is a sound transducer design primarily intended to increase the electrical efficiency of the element by eliminating the stress on the diaphragm characteristic of many other magnetic transducer systems. As shown schematically in the left diagram, it consists of a moving magnetic armature that is pivoted so it can move in the field of the permanent magnet. When precisely centered in the magnetic field there is no net force on the armature, hence the term 'balanced'. As illustrated in the right diagram, when there is electric current through the coil, it magnetizes the armature one way or the other, causing it to rotate slightly one way or the other about the pivot thus moving the diaphragm to make sound.


title: Headphones

text: The design is not mechanically stable; a slight imbalance makes the armature stick to one pole of the magnet. A fairly stiff restoring force is required to hold the armature in the 'balance' position. Although this reduces its efficiency, this design can still produce more sound from less power than any other. Popularized in the 1920s as Baldwin Mica Diaphragm radio headphones, balanced armature transducers were refined during World War II for use in military sound powered telephones. Some of these achieved astonishing electro-acoustic conversion efficiencies, in the range of 20% to 40%, for narrow bandwidth voice signals.


title: Headphones

text: Today they are typically used only in in-ear headphones and hearing aids, where their high efficiency and diminutive size is a major advantage. They generally are limited at the extremes of the hearing spectrum (e.g. below 20 Hz and above 16 kHz) and require a better seal than other types of drivers to deliver their full potential. Higher-end models may employ multiple armature drivers, dividing the frequency ranges between them using a passive crossover network. A few combine an armature driver with a small moving-coil driver for increased bass output.


title: Headphones

text: The thermoacoustic effect generates sound from the audio frequency Joule heating of the conductor, an effect that is not magnetic and does not vibrate the speaker.


title: Headphones

text: In 2013 a carbon nanotube thin-yarn earphone based on the thermoacoustic mechanism was demonstrated by a research group in Tsinghua University. The as-produced CNT thin yarn earphone has a working element called CNT thin yarn thermoacoustic chip. Such a chip is composed of a layer of CNT thin yarn array supported by the silicon wafer, and periodic grooves with certain depth are made on the wafer by micro-fabrication methods to suppress the heat leakage from the CNT yarn to the substrate.


title: Headphones

text: Transducer technologies employed much less commonly for headphones include the Heil Air Motion Transformer (AMT); Piezoelectric film; Ribbon planar magnetic; Magnetostriction and Plasma or Ionic. The first Heil AMT headphone was marketed by ESS Laboratories and was essentially an ESS AMT tweeter from one of the company's speakers being driven at full range. Since the turn of the century, only Precide of Switzerland have manufactured an AMT headphone. Piezoelectric film headphones were first developed by Pioneer, their two models used a flat sheet of film that limited the maximum volume of air movement. Currently, TakeT produces a piezoelectric film headphone shaped similarly to an AMT transducer but, which like the Precide driver, has a variation in the size of transducer folds over the diaphragm. It additionally incorporates a two way design by its inclusion of a dedicated tweeter/supertweeter panel. The folded shape of a diaphragm allows a transducer with a larger surface area to fit within smaller space constraints. This increases the total volume of air that can be moved on each excursion of the transducer given that radiating area. Due to the small volume of air in a headphone, the plasma or ionic transducer can become a full range driver although the high temperatures and voltages of these types makes them very rare with only the Plasmasonic being commercial.


title: Headphones

text: Magnetostriction headphones, sometimes sold under the label "Bonephones", work by vibrating against the side of head, transmitting sound via bone conduction. This is particularly helpful in situations where the ears must be unobstructed, or for people who are deaf for reasons that don't affect the nervous apparatus of hearing. Magnetostriction headphones though, are limited in their fidelity compared to conventional headphones that rely on the normal workings of the ear. Additionally, in the mid 1980s, a French company called Audio Reference tried to market the Plasmasonic plasma headphone invented by Henri Bondar. There are no known functioning examples left. Due to the small volume of air in a headphone, the plasma or ionic transducer can become a full range driver although the high temperatures and voltages needed makes them very rare.


title: Headphones

text: Headphones can prevent other people from hearing the sound, either for privacy or to prevent disturbing others, as in listening in a public library. They can also provide a level of sound fidelity greater than loudspeakers of similar cost. Part of their ability to do so comes from the lack of any need to perform room correction treatments with headphones. High-quality headphones can have an extremely flat low-frequency response down to 20 Hz within 3 dB. While a loudspeaker must use a relatively large (often 15" or 18") speaker driver to reproduce low frequencies, headphones can accurately reproduce bass and sub-bass frequencies with speaker drivers only 40-50 millimeters wide (or much smaller, as is the case with in-ear monitor headphones). Headphones' impressive low-frequency performance is possible because they are so much closer to the ear that they only need to move relatively small volumes of air.


title: Headphones

text: Marketed claims such as 'frequency response 4 Hz to 20 kHz' are usually overstatements; the product's response at frequencies lower than 20 Hz is typically very small.


title: Headphones

text: Headphones are also useful for video games that use 3D positional audio processing algorithms, as they allow players to better judge the position of an off-screen sound source (such as the footsteps of an opponent or their gunfire).


title: Headphones

text: Although modern headphones have been particularly widely sold and used for listening to stereo recordings since the release of the Walkman, there is subjective debate regarding the nature of their reproduction of stereo sound. Stereo recordings represent the position of horizontal depth cues (stereo separation) via volume and phase differences of the sound in question between the two channels. When the sounds from two speakers mix, they create the phase difference the brain uses to locate direction. Through most headphones, because the right and left channels do not combine in this manner, the illusion of the phantom center can be perceived as lost. Hard panned sounds are also heard only in one ear rather than from one side.


title: Headphones

text: Binaural recordings use a different microphone technique to encode direction directly as phase, with very little amplitude difference below 2 kHz, often using a dummy head. They can produce a surprisingly lifelike spatial impression through headphones. Commercial recordings almost always use stereo recording, rather than binaural, because loudspeaker listening is more common than headphone listening.


title: Headphones

text: It is possible to change the spatial effects of stereo sound on headphones, to better approximate the presentation of speaker reproduction, by using frequency-dependent cross-feed between the channels.


title: Headphones

text: Headsets can have ergonomic benefits over traditional telephone handsets. They allow call center agents to maintain better posture without needing to hand-hold a handset or tilt their head sideways to cradle it.


title: Headphones

text: Using headphones at a sufficiently high volume level may cause temporary or permanent hearing impairment or deafness. The headphone volume often has to compete with the background noise, especially in loud places such as subway stations, aircraft, and large crowds. Extended periods of exposure to high sound pressure levels created by headphones at high volume settings may be damaging to hearing; Nearly 50% of teenagers and young adults (12 to 35 years old) in middle and high income countries listen to unsafe levels of sound on their personal audio devices and smartphones. However, one hearing expert found in 2012 (before the worldwide adoption of smartphones as the main personal listening devices) that "fewer than 5% of users select volume levels and listen frequently enough to risk hearing loss." The International Telecommunication Union recently published "Guidelines for safe listening devices/systems" recommended that sound exposure not exceed 80 decibels, A-weighted dB(A) for a maximum of 40 hours per week. The European Union have also set a similar limit for users of personal listening devices (80 dB(A) for no more than 40 hours per week) and for each additional increase of 3-dB in sound exposure, the duration should be cut in half (83 dB(A) for no more than 20 hours, 86 dB(A) for 10 hours per week, 89 dB(A) for 5 hours per week and so on. Most major manufactures of smartphones now include some safety or volume limiting features and warning messaging in their devices. though such practices have received mixed response from some segments of the buying who favor the personal choice of setting their own volume levels.


title: Headphones

text: The usual way of limiting sound volume on devices driving headphones is by limiting output power. This has the additional undesirable effect of being dependent of the efficiency of the headphones; a device producing the maximum allowed power may not produce adequate volume when paired with low-efficiency, high-impedance equipment, while the same amount of power can reach dangerous levels with very efficient earphones.


title: Headphones

text: Some studies have found that people are more likely to raise volumes to unsafe levels while performing strenuous exercise. A Finnish study recommended that exercisers should set their headphone volumes to half of their normal loudness and only use them for half an hour.


title: Headphones

text: Other than hearing risk, there is a general danger that listening to loud music in headphones can distract the listener and lead to injury and accidents. Noise-cancelling headphones add extra risk. Several countries and states have made it illegal to wear headphones while driving or cycling.


title: Headphones

text: There have also been numerous reports of contact dermatitis due to exposure to in-ear headphones such as Apple AirPods. The contact dermatitis would be caused by in-ear headphones that contain gold, rubber, dyes, acrylates, or methacrylates. However, there have been no studies done to prove that exposure to in-ear headphones will cause contact dermatitis, rather that there is a correlation between in-ear headphone use and contact dermatitis cases.


title: Headphones

text: Hearing risk from headphones' use also applies to workers who must wear electronic or communication headsets as part of their daily job (i.e., pilots, call center and dispatch operators, sound engineers, firefighters, etc.) and hearing damage depends on the exposure time. The National Institute for Occupational Safety and Health (NIOSH) recommends sound exposure not exceed 85 dB(A) over 8 hour work day as a time-weighted average. NIOSH uses the 3-dB exchange rate often referred to as "time-intensity tradeoff" which means if sound exposure level is increased by 3 decibels, the duration of exposure should be cut in half. NIOSH published several documents targeted at protecting the hearing of workers who must wear communication headsets such as call center operators, firefighters, and musicians and sound engineers.


title: Southwestern United States

text: The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, Nevada, Oklahoma, Texas, and Utah. The largest cities by metropolitan area are Phoenix, Las Vegas, El Paso, Albuquerque, and Tucson. Prior to 1848, in the historical region of Santa Fe de Nuevo México as well as parts of Alta California and Coahuila y Tejas, settlement was almost non-existent outside of Nuevo México's Pueblos and Spanish or Mexican municipalities. Much of the area had been a part of New Spain and Mexico until the United States acquired the area through the Treaty of Guadalupe Hidalgo in 1848 and the smaller Gadsden Purchase in 1854.


title: Southwestern United States

text: While the region's boundaries are not officially defined, there have been attempts to do so. One such definition is from the Mojave Desert in California in the west (117° west longitude) to Carlsbad, New Mexico in the east (104° west longitude); another says that it extends from the Mexico–United States border in the south to the southern areas of Colorado, Utah, and Nevada in the north (39° north latitude). In another definition, the core Southwestern U.S. includes only the states of Arizona and New Mexico; others focus on the land within the old Spanish and Mexican borders of the "Nuevo México" Province or the later American New Mexico Territory.


title: Southwestern United States

text: Distinct elements of the Western lifestyle thrive in the region, such as Western wear and Southwestern cuisines, including Native American, New Mexican, and Tex-Mex, or various genres of Western music like Indigenous, New Mexico, and Tejano music styles. Likewise with the sought-after Southwestern architectural styles in the region inspired by blending Pueblo and Territorial styles, with Mediterranean Revival, Spanish Colonial architecture, Mission Revival architecture, Pueblo Deco, and Ranch-style houses in the form of the amalgamated Pueblo Revival and Territorial Revival architectures. This is due to the region's influence by the Native American (especially Apache, Pueblo, and Navajo), Hispano, vaquero, and later American frontier cowboy history.


title: Southwestern United States

text: The geography of the region is mainly made up of four features: the Mojave, Sonoran, and Chihuahuan Deserts, and the Colorado Plateau; although there are other geographical features as well, such as a portion of the Great Basin Desert. The deserts dominate the southern and western reaches of the area, while the plateau (which is largely made up of high desert) is the main feature north of the Mogollon Rim. The two major rivers of the region are the Colorado River, running in the northern and western areas, and the Rio Grande, running in the east, north to south.


title: Southwestern United States

text: Formed approximately 8000 years ago, the Chihuahuan Desert is a relatively dry desert, although it is slightly wetter than the Sonoran Desert to the west. The Chihuahuan Desert spreads across the southeastern portion of the region, covering from southeastern Arizona, across southern New Mexico, and the portion of western Texas included in the Southwest. While it is the second largest desert in the United States, only a third of the desert is within the United States, with the rest in Mexico. El Paso and Albuquerque are the major US cities in this desert, with other smaller cities being Las Cruces and Roswell in New Mexico and Willcox in Arizona.


title: Southwestern United States

text: The elevation in the Chihuahuan varies from about , as there are several larger mountain ranges, such as the Organ Mountains, the Guadalupe Mountains, and the Chiracahua Mountains, plus many smaller mountain ranges contained in the area, namely the Animas, San Andres, and Doña Ana Mountains in New Mexico; and the Franklin, Hueco, and Davis Mountains in Texas. It also reaches up into the foothills of the higher ranges such as the Black Range and Oscura Mountains in New Mexico. High above the desert, these forest-covered and sometimes snow-capped mountains form sky islands, with radically different flora and fauna than the surrounding desert below. The sky islands also supply the surrounding desert foothills with flowing water during the spring runoff and after the summer storms of the New Mexican monsoon season. The Chihuahuan is a "rain shadow" desert, formed between two mountain ranges (the Sierra Madre Occidental on the west and the Sierra Madre Oriental on the east) which block oceanic precipitation from reaching the area. The Chihuahuan Desert is considered the "most biologically diverse desert in the Western Hemisphere and one of the most diverse in the world", and includes more species of cacti than any other desert in the world. The most prolific plants in this region are agave, yucca and creosote bushes, in addition to the ubiquitous presence of various cacti species.


title: Southwestern United States

text: When people think of the desert southwest, the landscape of the Sonoran Desert is what mostly comes to mind. The Sonoran Desert makes up the southwestern portion of the Southwest; most of the desert lies in Mexico, but its United States component lies on the southeastern border of California, and the western 2/3 of southern Arizona. Rainfall averages between per year, and the desert's most widely known inhabitant is the saguaro cactus, which is unique to the desert. It is bounded on the northwest by the Mojave Desert, to the north by the Colorado Plateau and to the east by the Arizona Mountains forests and the Chihuahuan Desert. Aside from the trademark saguaro, the desert has the most diverse plant life of any desert in the world, and includes many other species of cacti, including the organ-pipe, senita, prickly pear, barrel, fishhook, hedgehog, cholla, silver dollar, and jojoba. The portion of the Sonora Desert which lies in the Southwestern United States is the most populated area within the region. Six of the top ten major population centers of the region are found within its borders: Phoenix, Tucson, Mesa, Chandler, Glendale, and Scottsdale, all in Arizona. Also within its borders are Yuma and Prescott Arizona.


title: Southwestern United States

text: The most northwest portion of the American Southwest is covered by the Mojave Desert. Bordered on the south by the Sonoran Desert and the east by the Colorado Plateau, its range within the region makes up the southeast tip of Nevada, the southwestern corner of Utah and the northwestern corner of Arizona. In terms of topography, the Mojave is very similar to the Great Basin Desert, which lies just to its north. Within the region, Las Vegas is the most populous city; other significant population centers include Laughlin and Pahrump in Nevada, St. George and Hurricane in Utah, and Lake Havasu City, Kingman, and Bullhead City in Arizona. The Mojave is the smallest, driest and hottest desert within the United States. The Mojave gets less than of rain annually, and its elevation ranges from above sea level. The most prolific vegetation is the tall Joshua tree, which grow as tall as , and are thought to live almost 1000 years. Other major vegetation includes the Parry saltbush and the Mojave sage, both only found in the Mojave, as well as the creosote bush.


title: Southwestern United States

text: The Colorado Plateau varies from the large stands of forests in the west, including the largest stand of ponderosa pine trees in the world, to the Mesas to the east. Although not called a desert, the Colorado Plateau is mostly made up of high desert. Within the Southwest U.S. region, the Colorado is bordered to the south by the Mogollon Rim and the Sonoran Desert, to the west by the Mojave Desert, and to the east by the Rocky Mountains, the Rio Grande Rift valley, and the Llano Estacado. The Plateau is characterized by a series of plateaus and mesas, interspersed with canyons. The most dramatic example is the Grand Canyon. But that is one of many dramatic vistas included within the Plateau, which includes spectacular lava formations, "painted" deserts, sand dunes, and badlands. One of the most distinctive features of the Plateau is its longevity, having come into existence at least 500 million years ago. The Plateau can be divided into six sections, three of which fall into the Southwest region. Beginning with the Navajo section forming the northern boundary of the Southwestern United States, which has shallower canyons than those in the Canyonlands section just to its north; the Navajo section is bordered to the south by the Grand Canyon section, which of course is dominated by the Grand Canyon; and the southeasternmost portion of the Plateau is the Datil section, consisting of valleys, mesas, and volcanic formations. Albuquerque is the most populous city often considered at the edge of this portion contained in the Southwest region, but Santa Fe, New Mexico and Flagstaff, Arizona, are also significant population centers.


title: Southwestern United States

text: Phoenix, Tucson, and Las Vegas dominate the westernmost metropolitan areas in the Southwest, while Albuquerque, and El Paso dominate the easternmost metropolitan areas.


title: Southwestern United States

text: Human history in the Southwest begins with the arrival of the Clovis culture, a Paleo-Indian hunter-gatherer culture which arrived sometime around 9000 BC. This culture remained in the area for several millennia. At some point they were replaced by three great Pre-Columbian Indian cultures: the Ancestral Pueblo people, the Hohokam, and the Mogollon, all of which existed among other surrounding cultures including the FremontPatayan. Maize began to be cultivated in the region sometime during the early first millennium BC, but it took several hundred years for the native cultures to be dependent on it as a food source. As their dependence on maize grew, Pre-Columbian Indians began developing irrigation systems around 1500.


title: Southwestern United States

text: According to archeological finds, the Ancestral Pueblo people, also known as the Anasazi (although that term is becoming more and more disused), began settling in the area in approximately 1500 BC. Eventually, they would spread throughout the entire northern section of the Southwest. This culture would go through several different eras lasting from approximately 1500 BC through the middle of the 15th century AD: the Basketmaker I, II, and III phases followed by the Pueblo I, II, III, and IV. As the Puebloans transitioned from a nomadic lifestyle to one based on agriculture, their first domiciles were pithouses. The Mogollon culture developed later than the Puebloan, arising in the eastern area of the region at around 300 BC. Their range would eventually extend deep into what would become Mexico, and dominate the southeastern portion of the Southwest. Their settlements would evolve over time from pit-dwellings through pueblos and finally also incorporating cliff-dwellings. The Hohokam were the last of these ancestral cultures to develop, somewhere around AD 1, but they would grow to be the most populous of the three by AD 1300, despite being the smallest of the three in terms of area, covering most of the southwest portion. Beginning in approximately AD 600, the Hohokam began to develop an extensive series of irrigation canals; of the three major cultures in the Southwest, only the Hohokam developed irrigation as a means of watering their agriculture.


title: Southwestern United States

text: Not long after the Hohokam reached the height of their culture, all three major cultures in the Southwest began to decline for unknown reasons, although severe drought and encroachment from other peoples have been postulated. By the end of the 15th century, all three cultures had disappeared. The modern Indian tribes of the Isleta, Hopi, Zuni, Sandia, Cochiti, Santa Ana, Taos, Acoma, and Laguna trace their ancestry back to the ancestral Puebloans, while the Akimel O'odham and Tohono O'odham claim descent from Hohokam. The area previously occupied by the Mogollon was taken over by an unrelated tribe, the Apache. While it is unclear whether any of the modern Indian tribes are descended from the Mogollon, some archeologists and historians believe that they mixed with Ancestral Puebloans and became part of the Hopi and Zuni.


title: Southwestern United States

text: Prior to the arrival of Europeans, the Southwestern United States was inhabited by a very large population of American Indian tribes. The area once occupied by the ancestral Puebloans became inhabited by several American Indian tribes, the most populous of which were the Navajo, Ute, Southern Paiute, and Hopi. The Navajo, along with the Hopi, were the earliest of the modern Indian tribes to develop in the Southwest. Around AD 1100 their culture began to develop in the Four Corners area of the region. The Navahos migrated from northwestern Canada and eastern Alaska, where the majority of Athabaskan speakers reside. The Ute were found over most of modern-day Utah and Colorado, as well as northern New Mexico and Arizona. The Paiutes roamed an area which covered over 45,000 square miles of southern Nevada and California, south-central Utah, and northern Arizona. The Hopi settled the lands of the central and western portions of northern Arizona. Their village of Oraibi, settled in approximately AD 1100, is, along with Acoma Sky City in New Mexico, one of the oldest continuously occupied settlements in the United States. The Mogollon area became occupied by the Apaches and the Zuni. The Apache migrated into the American Southwest from the northern areas of North America at some point between 1200 and 1500. They settled throughout New Mexico, eastern Arizona, northern Mexico, parts of western Texas, and southern Colorado. The Zuni count their direct ancestry through the ancestral Puebloans. The modern-day Zuni established a culture along the Zuni River in far-eastern Arizona and western New Mexico. Both major tribes of the O'odham tribe settled in the southern and central Arizona, in the lands once controlled by their ancestors, the Hohokam.


title: Southwestern United States

text: The first European intrusion into the region came from the south. In 1539, a Jesuit Franciscan named Marcos de Niza led an expedition from Mexico City which passed through eastern Arizona. The following year Francisco Vázquez de Coronado, based on reports from survivors of the Narváez expedition (1528–36) who had crossed eastern Texas on their way to Mexico City, led an expedition to discover the Seven Golden Cities of Cíbola. The 1582-3 expedition of Antonio de Espejo explored New Mexico and eastern Arizona; and this led to Juan de Oñate's establishment of the Spanish province of Santa Fe de Nuevo México in 1598, with a capital founded near Ohkay Oweenge Pueblo, which he called San Juan de los Caballeros. Oñate's party also attempted to establish a settlement in Arizona in 1599, but were turned back by inclement weather. In 1610, Santa Fe was founded, making it the oldest capital in United States.


title: Southwestern United States

text: In 1664 Juan Archuleta led an expedition into what is now Colorado, becoming the first European to enter. A second Spanish expedition was led into Colorado by Juan Ulibarrí in 1706, during which he claimed the Colorado territory for Spain.


title: Southwestern United States

text: From 1687 to 1691 the Jesuit priest, Eusebio Kino established several missions in the Santa Cruz River valley; and Kino further explored southern and central Arizona in 1694, during which he discovered the ruins of Casa Grande. Beginning in 1732, Spanish settlers began to enter the region, and the Spanish started bestowing land grants in Mexico and the Southwest US. In 1751, the O'odham rebelled against the Spanish incursions, but the revolt was unsuccessful. In fact, it had the exact opposite effect, for the result of the rebellion was the establishment of the presidio at Tubac, the first permanent European settlement in Arizona.


title: Southwestern United States

text: In 1768, the Spanish created the Provincia de las Californias, which included California and the Southwest US. Over approximately the next 50 years, the Spanish continued to explore the Southwest, and in 1776 the City of Tucson was founded when the Presidio San Augustin del Tucson was created, relocating the presidio from Tubac.


title: Southwestern United States

text: In 1776, two Franciscan priests, Francisco Atanasio Domínguez and Silvestre Vélez de Escalante, led an expedition from Santa Fe heading to California. After passing through Colorado, they became the first Europeans to travel into what is now Utah. Their journey was halted by bad weather in October, and they turned back, heading south into Arizona before turning east back to Santa Fe.


title: Southwestern United States

text: In 1804 Spain divided the Provincia de las Californias, creating the province Alta California, which consisted primarily of what would become California, Nevada, Arizona, Colorado, Utah and New Mexico. In 1821 Mexico achieved its independence from Spain and shortly after, in 1824, developed its constitution, which established the Alta California territory, which was the same geographic area as the earlier Spanish province.


title: Southwestern United States

text: In 1825, Arizona was visited by its first non-Spanish Europeans, English trappers. In 1836, the Republic of Texas, which contained the easternmost of the Southwest United States, won its independence from Mexico. In 1845 the Republic of Texas was annexed by the United States and immediately became a state, bypassing the usual territory phase. The new state still contained portions of what would eventually become parts of other states. In 1846, the Southwest became embroiled in the Mexican–American War, partly as a result of the United States' annexation of Texas. On August 18, 1846, an American force captured Santa Fe, New Mexico. On December 16 of the same year, American forces captured Tucson, Arizona, marking the end of hostilities in the Southwest United States. When the war ended with the Treaty of Guadalupe Hidalgo on February 2, 1848, the United States gained control of all of present-day California, Nevada and Utah, as well as the majority of Arizona, and parts of New Mexico and Colorado (the rest of present-day Colorado, and most of New Mexico had been gained by the United States in their annexation of the Republic of Texas). The final portion of the Southwestern United States came about through the acquisition of the southernmost parts of Arizona and New Mexico through the Gadsden Purchase in 1853.


title: Southwestern United States

text: Of the states of which at least a portion make up the Southwest, Texas was the first to achieve statehood. On December 29, 1845, the Republic of Texas was annexed, bypassing the status of becoming a territory, and immediately became a state. Initially, its borders included parts of what would become several other states: almost half of New Mexico, a third of Colorado, and small portions of Kansas, Oklahoma, and Wyoming. Texas current borders were set in the Compromise of 1850, where Texas ceded land to the federal government in exchange for $10 million, which would go to paying off the debt Texas had accumulated in its war with Mexico.


title: Southwestern United States

text: Following the Mexican Cession, the lands of what had been the Mexican territory of Alta California were in flux: portions of what is now New Mexico were claimed, but never controlled, by Texas. With the Compromise of 1850, the states of Texas and California were created (Texas as a slave state, and California as a free state), as well as the Utah Territory and New Mexico Territory. The New Mexico Territory consisted of most of Arizona and New Mexico (excluding a strip along their southern borders), a small section of southern Colorado, and the very southern tip of Nevada; while the Utah Territory consisted of Utah, most of Nevada, and portions of Wyoming and Colorado. The New Mexico Territory was expanded along its southern extent, to its current border, with the signing of the Gadsden Purchase Treaty on December 30, 1853, which was ratified by the U.S. Congress, with some slight alterations, in April 1854.


title: Southwestern United States

text: The Colorado Territory was organized on February 28, 1861, created out of lands then currently in the Utah, Kansas, Nebraska, and New Mexico territories. The Nevada Territory was also organized in 1861, on March 2, with land taken from the existing Utah Territory. Initially, only the western 2/3 of what is currently the State of Nevada was included in the territory, with its boundary to the east being the 39th meridian west from Washington, and to the south the 37th parallel. In 1862 Nevada's eastern border shifted to the 38th meridian west from Washington, and finally to its current position at the 37th meridian west from Washington in 1866. The boundary modification in 1866 also included adding the southern triangular tip of the present-day state, taken from the Arizona Territory.


title: Southwestern United States

text: From July 24–27, 1861 a Confederate force under the command of Lt. Colonel John Robert Baylor forced the surrender of the small Union garrison stationed at Fort Fillmore, near Mesilla, New Mexico. On August 1, 1861, Baylor declared the creation of the Arizona Territory, and claimed it for the Confederacy, with Mesilla as its capital. The territory, which had been formed by the portion of the existing New Mexico Territory below the 34th parallel, became official on February 14, 1862.


title: Southwestern United States

text: Nevada was admitted to the Union on October 31, 1864, becoming the 36th state. This was followed by the admittance to the Union of Colorado, which became the 38th state on August 1, 1876. Confederate Arizona was short-lived, however. By May 1862, Confederate forces had been driven out of the region by union troops. That same month a bill was introduced into the U.S. Congress, and on February 24, 1863 Abraham Lincoln signed the Arizona Organic Act, which officially created the U.S. Territory of Arizona, splitting the New Mexico Territory at the 107th meridian.


title: Southwestern United States

text: Utah, as shown above, evolved out of the Utah Territory, as pieces of the original territory created in 1850 were carved out: parts were ceded to Nevada, Wyoming, and Colorado in 1861; another section to Nevada in 1862; and the final section to Nevada in 1866. In 1890, the LDS church issued the 1890 Manifesto, which officially banned polygamy for members of the church. It was the last roadblock for Utah entering the Union, and on January 4, 1896, Utah was officially granted statehood, becoming the 45th state.


title: Southwestern United States

text: In 1869, John Wesley Powell led a 3-month expedition which explored the Grand Canyon and the Colorado River. In 1875, he would publish a book describing his explorations, "Report of the Exploration of the Columbia River of the West and Its Tributaries", which was later republished as "The Exploration of the Colorado River and Its Canyons".


title: Southwestern United States

text: In 1877 silver was discovered in southeastern Arizona. The notorious mining town of Tombstone, Arizona was born to service the miners. The town would become immortalized as the scene of what is considered the greatest gunfight in the history of the Old West, the Gunfight at the O.K. Corral.


title: Southwestern United States

text: Copper was also discovered in 1877, near Bisbee and Jerome in Arizona, which became an important component of the economy of the Southwest. Production began in 1880 and was made more profitable by the expansion of the railroad throughout the territory during the 1880s.


title: Southwestern United States

text: The early 1880s also saw the completion of the second transcontinental railroad, which ran through the heart of the Southwest, called the "Santa Fe Route". It ran from Chicago, down through Topeka, then further south to Albuquerque, before heading almost due west through northern Arizona to Los Angeles.


title: Southwestern United States

text: The repeal of the Sherman Silver Purchase Act in 1893 led to the decline of the silver mining industry in the region.


title: Southwestern United States

text: In 1901, the Santa Fe Railroad reached the South Rim of the Grand Canyon, opening the way for a tourism boom, a trend led by restaurant and hotel entrepreneur Fred Harvey.


title: Southwestern United States

text: The last two territories within the Southwest to achieve statehood were New Mexico and Arizona. By 1863, with the splitting off of the Arizona Territory, New Mexico reached its modern borders. They became states within forty days of one another. On January 6, 1912, New Mexico became the 47th state in the Union. Arizona would shortly follow, becoming the last of the 48 contiguous United States on February 14, 1912.


title: Southwestern United States

text: The 1930s saw the beginning of the ski industry in the Southwest. Resorts were established in Colorado in areas such as Estes Park, Gunnison, and on Loveland Pass. New Mexico's oldest ski area is Sandia Peak Ski Area at the eastern edge of Albuquerque, which opened to skiers in 1936. At the end of the decade, in 1939, with the establishment of Alta Ski Area, Utah's skiing began to be developed.


title: Southwestern United States

text: Due to the ski conditions in the state, during WWII, the 10th Mountain Division established Camp Hale in Colorado to train elite ski troops.


title: Southwestern United States

text: While this article deals with the core definition for the American Southwest, there are many others. The various definitions can be broken down into four main categories: Historical/Archeological; Geological/Topographical; Ecological; and Cultural. In the 1930s and 1940s, many definitions of the Southwest included all or part of Texas, Oklahoma, New Mexico, Arizona, California, Colorado, and Utah. As time has gone on, the definition of the Southwest has become more solidified and more compact. For example, in 1948 the National Geographic Society defined the American Southwest as all of California, Nevada, Utah, Arizona, Colorado, and New Mexico, and the southernmost sections of Oregon, Idaho, and Wyoming, as well as parts of southwest Nebraska, western Kansas, Oklahoma, and Texas. By 1977, the Society's definition had narrowed to only the four states of Utah, Arizona, Colorado, and New Mexico; and by 1982 the portion of the Southwest in the United States, as defined by the Society, had shrunk to Arizona and New Mexico, with the southernmost strip of Utah and Colorado, as well as the Mojave and Colorado deserts in California. Other individuals who focus on Southwest studies who favored a more limited extent of the area to center on Arizona and New Mexico, with small parts of surrounding areas, include Erna Fergusson, Charles Lummis (who claimed to have coined the term, the Southwest), and cultural geographer Raymond Gastil, and ethnologist Miguel León-Portilla.


title: Southwestern United States

text: Geographer D. W. Meinig defines the Southwest in a very similar fashion to Reed: the portion of New Mexico west of the Llano Estacado and the portion of Arizona east of the Mojave-Sonoran Desert and south of the "canyon lands" and also including the El Paso district of western Texas and the southernmost part of Colorado. Meinig breaks the Southwest down into four distinct subregions. He calls the first subregion "Northern New Mexico", and describes it as focused on Albuquerque and Santa Fe. It extends from the San Luis Valley of southern Colorado to south of Socorro and including the Manzano Mountains, with an east–west breadth in the north stretching from the upper Canadian River to the upper San Juan River. The area around Albuquerque is sometimes called Central New Mexico.


title: Southwestern United States

text: "Central Arizona" is a vast metropolitan area spread across one contiguous sprawling oasis, essentially equivalent to the Phoenix metropolitan area. The city of Phoenix is the largest urban center, and located in the approximate center of the area that includes Tempe, Mesa, and many others.


title: Southwestern United States

text: Meinig calls the third subregion "El Paso, Tucson, and the Southern Borderlands". While El Paso and Tucson are distinctly different cities, they serve as anchor points to the hinterland between them. Tucson occupies a large oasis at the western end of the El Paso-Tucson corridor. The region between the two cities is a major transportation trunk with settlements servicing both highway and railway needs. There are also large mining operations, ranches, and agricultural oases. Both El Paso and Tucson have large military installations nearby; Fort Bliss and White Sands Missile Range north of El Paso in New Mexico, and, near Tucson, the Davis-Monthan Air Force Base. About to the southeast are the research facilities at Fort Huachuca. These military installations form a kind of hinterland around the El Paso-Tucson region, and are served by scientific and residential communities such as Sierra Vista, Las Cruces, and Alamogordo. El Paso's influence extends north into the Mesilla Valley, and southeast along the Rio Grande into the Trans-Pecos region of Texas.


title: Southwestern United States

text: The fourth subregion Meinig calls the "Northern Corridor and Navajolands", a major highway and railway trunk which connects Albuquerque and Flagstaff. Just north of the transportation trunk are large blocks of American Indian land.


title: Southwestern United States

text: As the US expanded westward, the country's western border also shifted westward, and consequently, so did the location of the Southwestern and Northwestern United States. In the early years of the United States, newly colonized lands lying immediately west of the Appalachian Mountains were detached from North Carolina and given the name Southwest Territory. During the decades that followed, the region known as "the Southwestern United States" covered much of the Deep South east of the Mississippi River.


title: Southwestern United States

text: However, as territories and eventual states to the west were added after the Mexican–American War, the geographical "Southwest" expanded, and the relationship of these new acquisitions to the South itself became "increasingly unclear."


title: Southwestern United States

text: However, archeologist, Erik Reed, gives a description which is the most widely accepted as defining the American Southwest, which runs from Durango, Colorado in the north, to Durango, Mexico, in the south, and from Las Vegas, Nevada in the west to Las Vegas, New Mexico in the East. Reed's definition is roughly equivalent to the western half of the Learning Center of the American Southwest's definition, leaving out any portion of Kansas and Oklahoma, and much of Texas, as well as the eastern half of New Mexico. Since this article is about the Southwestern United States, the areas of Sonora and Chihuahua in Mexico will be excluded. The portion left includes Arizona and western New Mexico, the very southernmost part of Utah, southwestern Colorado, the very tip of west Texas, and triangle formed by the southern tip of Nevada. This will be the defined scope that is used in this article unless otherwise specified in a particular area.


title: Southwestern United States

text: Parts of the other states make up the various areas that can be included in the Southwest, depending on the source. The Learning Center of the American Southwest (LCAS) does not rely on current state boundaries, and defines the American Southwest as parts of Arizona, Colorado, Kansas, New Mexico, Oklahoma, Texas, and Utah.


title: Southwestern United States

text: From this perspective, almost all of the region's physiographical traits, geological formations, and weather are contained within a box between 26° and 38° northern latitude, and 98° 30' and 124° western longitude.


title: Southwestern United States

text: When looking at the fauna of the region, there is a broader definition of the American Southwest. The Southwestern Center for Herpetological Research defines the Southwest as being only the states of Arizona, New Mexico, with parts of California, Nevada, Texas, and Utah; although they include all of those six states in their map of the region, solely for ease of defining the border.


title: Southwestern United States

text: Lawrence Clark Powell, a major bibliographer whose emphasis is on the Southwest, defined the American Southwest in a 1958 "Arizona Highways" article as, "the lands lying west of the Pecos, north of the [Mexican] Border, south of the Mesa Verde and the Grand Canyon, and east of the mountains which wall off Southern California and make it a land in itself."


title: Southwestern United States

text: Texas has long been the focal point of this dichotomy, and is often considered, as such, the "core area" of "the South's Southwest." While the Trans-Pecos area is generally acknowledged as part of the "desert Southwest", most of Texas and large parts of Oklahoma are often placed into a sub-region of the South, which some consider southwestern in the general framework of the original application, meaning the "Western South". This is an area containing the basic elements of Southern history, culture, politics, religion, and linguistic and settlement patterns, yet blended with traits of the frontier West. While this particular Southwest is notably different in many ways from the classic "Old South" or Southeast, these features are strong enough to give it a separate southwestern identity quite different in nature from that of the interior southwestern states to the west.


title: Southwestern United States

text: One of these distinguishing characteristics in Texas—in addition to having been a Confederate state during the Civil War—is that Indigenous and Spanish American culture never played a central role in the development of this area in relative comparison to the others, as the vast majority of settlers were Anglo and blacks from the South. Although the present-day state of Oklahoma was Indian Territory until the early 20th century, many of these American Indians were from the southeastern United States and became culturally assimilated early on. The majority of members of these tribes also allied themselves with the Confederacy during the Civil War. Combined with that, once the territory was open for settlement, southeastern pioneers made up a disproportionate number of these newcomers. All this contributed to the new state having a character that differed from other parts of the Southwest with large American Indian populations.