title: Al-Aqsa Mosque

text: The mosque's interior is supported by 45 columns, 33 of which are white marble and 12 of stone. The column rows of the central aisles are heavy and stunted. The remaining four rows are better proportioned. The capitals of the columns are of four different kinds: those in the central aisle are heavy and primitively designed, while those under the dome are of the Corinthian order, and made from Italian white marble. The capitals in the eastern aisle are of a heavy basket-shaped design and those east and west of the dome are also basket-shaped, but smaller and better proportioned. The columns and piers are connected by an architectural rave, which consists of beams of roughly squared timber enclosed in a wooden casing.


title: Al-Aqsa Mosque

text: A great portion of the mosque is covered with whitewash, but the drum of the dome and the walls immediately beneath it are decorated with mosaics and marble. Some paintings by an Italian artist were introduced when repairs were undertaken at the mosque after an earthquake ravaged the mosque in 1927. The ceiling of the mosque was painted with funding by King Farouk of Egypt.


title: Al-Aqsa Mosque

text: The "minbar" of the mosque was built by a craftsman named Akhtarini from Aleppo on the orders of the Zengid sultan Nur ad-Din. It was intended to be a gift for the mosque when Nur ad-Din would capture Jerusalem from the Crusaders and took six years to build (1168–74). Nur ad-Din died and the Crusaders still controlled Jerusalem, but in 1187, Saladin captured the city and the "minbar" was installed. The structure was made of ivory and carefully crafted wood. Arabic calligraphy, geometrical and floral designs were inscribed in the woodwork.


title: Al-Aqsa Mosque

text: After its destruction by Rohan in 1969, it was replaced by a much simpler "minbar". In January 2007, Adnan al-Husayni—head of the Islamic "waqf" in charge of al-Aqsa—stated that a new "minbar" would be installed; it was installed in February 2007. The design of the new "minbar" was drawn by Jamil Badran based on an exact replica of the Saladin Minbar and was finished by Badran within a period of five years. The "minbar" itself was built in Jordan over a period of four years and the craftsmen used "ancient woodworking methods, joining the pieces with pegs instead of nails, but employed computer images to design the pulpit ["minbar"]."


title: Al-Aqsa Mosque

text: The Waqf Ministry of Jordan held control of the al-Aqsa Mosque until the 1967 Six-Day War. After Israel's victory in that war, Israel transferred the control of the mosque and the northern Noble Sanctuary to the Islamic "waqf" trust, who are independent of the Israeli government. However, Israeli Security Forces are permitted to patrol and conduct searches within the perimeter of the mosque. After the 1969 arson attack, the "waqf" employed architects, technicians and craftsmen in a committee that carry out regular maintenance operations. The Islamic Movement in Israel and the "waqf" have attempted to increase Muslim control of the Temple Mount as a way of countering Israeli policies and the escalating presence of Israeli security forces around the site since the Second Intifada. Some activities included refurbishing abandoned structures and renovating.


title: Al-Aqsa Mosque

text: Muhammad Ahmad Hussein is the head imam and manager of the al-Aqsa Mosque and was assigned the role of Grand Mufti of Jerusalem in 2006 by Palestinian president Mahmoud Abbas. Ownership of the al-Aqsa Mosque is a contentious issue in the Israel-Palestinian conflict. Israel claims sovereignty over the mosque along with all of the Temple Mount (Noble Sanctuary), but Palestinians hold the custodianship of the site through the Islamic "waqf". During the negotiations at the 2000 Camp David Summit, Palestinians demanded complete ownership of the mosque and other Islamic holy sites in East Jerusalem.


title: Al-Aqsa Mosque

text: Muslim residents of Israel and Palestinians living in East Jerusalem are normally allowed to enter the Temple Mount and pray at the al-Aqsa Mosque without restrictions. Due to security measures, the Israeli government occasionally prevents certain groups of Muslims from reaching al-Aqsa by blocking the entrances to the complex; the restrictions vary from time to time. At times restrictions have prevented all men under 50 and women under 45 from entering, but married men over 45 are allowed. Sometimes the restrictions are enforced on the occasion of Friday prayers, other times they are over an extended period of time. Restrictions are most severe for Gazans, followed by restrictions on those from West Bank. The Israeli government states that the restrictions are in place for security reasons.


title: Al-Aqsa Mosque

text: Until 2000, non-Muslim visitors could enter the Al-Aqsa Mosque by getting a ticket from the Waqf. That procedure ended when the Second Intifada began. Fifteen years later, negotiation between Israel and Jordan might result in allowing visitors to enter once again.


title: Al-Aqsa Mosque

text: Several excavations outside the Temple Mount took place following the 1967 War. In 1970, Israeli authorities commenced intensive excavations outside the walls next to the mosque on the southern and western sides. Palestinians believed that tunnels were being dug under the Al-Aqsa Mosque in order to undermine its foundations, which was denied by Israelis, who claimed that the closest excavation to the mosque was some to its south. The Archaeological Department of the Israeli Ministry of Religious Affairs dug a tunnel near the western portion of the mosque in 1984. According to UNESCO's special envoy to Jerusalem Oleg Grabar, buildings and structures on the Temple Mount are deteriorating due mostly to disputes between the Israeli, Palestinian and Jordanian governments over who is actually responsible for the site.


title: Al-Aqsa Mosque

text: In February 2007, the department started to excavate a site for archaeological remains in a location where the government wanted to rebuild a collapsed pedestrian bridge leading to the Mughrabi Gate, the only entrance for non-Muslims into the Temple Mount complex. This site was away from the mosque. The excavations provoked anger throughout the Islamic world, and Israel was accused of trying to destroy the foundation of the mosque. Ismail Haniya—then Prime Minister of the Palestinian National Authority and Hamas leader—called on Palestinians to unite to protest the excavations, while Fatah said they would end their ceasefire with Israel. Israel denied all charges against them, calling them "ludicrous".


title: Al-Aqsa Mosque

text: In April 2021, during both Passover and Ramadan, the site was a focus of tension between Israeli settlers and Palestinians. Jewish settlers broke an agreement between Israel and Jordan and performed prayers and read from the Torah inside the compound, an area normally off limits to non-Muslims. On 14 April, Israeli police entered the area and forcibly cut wires to speakers in minarets around the mosque, silencing the call to prayer, claiming the sound was interfering with an event by the Israeli president at the Western Wall. On 16 April, seventy thousand Muslims prayed in the compound around the mosque, the largest gathering since the beginning of the COVID pandemic; police barred most from entering the structure itself. In May 2021, hundreds of Palestinians were injured following clashes in the compound after reports of Israel's intention to proceed to evict Palestinians from land claimed by Israeli settlers.


title: Al-Aqsa Mosque

text: On 15 April 2022, Israeli forces entered the Temple Mount and used tear gas shells and sound bombs to disperse Palestinians who, they said, were throwing stones at policemen. Some Palestinians barricaded themselves inside the Al-Aqsa mosque, where they were detained by Israeli police. Over 150 people ended up injured and 400 arrested.


title: Returnal (video game)

text: Returnal is a third-person shooter roguelike video game developed by Housemarque and published by Sony Interactive Entertainment. It was released for the PlayStation 5 on April 30, 2021. The game follows Selene Vassos, an astronaut who lands on the planet Atropos in search of the mysterious "White Shadow" signal and finds herself trapped in a time loop. "Returnal" received generally favorable reviews for its visuals, combat, audio design and technical achievements, though its difficulty and roguelike design were met with mixed opinions. It won several end-year accolades, including Best Game at the 18th British Academy Games Awards. The game is set to release on Windows in early 2023.


title: Returnal (video game)

text: "Returnal" is a third-person shooter video game featuring roguelike elements and covering the psychological horror genre. Set in a futuristic science fiction setting, the player controls Selene Vassos (Jane Perry), a space pilot, equipped with a suit and armed with high-tech weapons, who is stranded on the alien planet Atropos, and stuck in a time loop. After every death, Selene is resurrected, following a pattern of traversing foreign environments and combating extraterrestrial entities with growing visions in an ever changing world.


title: Returnal (video game)

text: The game is split into two halves- each consisting of three biomes. If the player dies during a run, they are sent to the beginning of the half. Selene has the ability to dash and can later unlock a grappling hook that lets her shoot to predefined points in a room. Players can find a variety of weapons in the game, ranging from a basic pistol to an Electropylon Driver. Each weapon has unique traits that can be leveled up to unlock enhanced perks that can deal more damage. Selene additionally has a melee weapon that can be used to attack enemies, destroy resource geodes, or destroy barriers.


title: Returnal (video game)

text: The "Ascension" update introduces online cooperative multiplayer, which allows up to two players to complete the game's campaign together.


title: Returnal (video game)

text: Disobeying orders, ASTRA Corporation explorer Selene Vassos attempts to land on the off-limits planet of Atropos to investigate what she dubs the "White Shadow" signal, which somehow seems familiar to her. Upon arrival, Selene's ship Helios suffers heavy damage and crash lands. Unable to contact ASTRA, Selene explores the planet and is shocked when she comes across corpses of herself. She learns that every time she dies, time loops back to the moment she crashed, sending her back to her starting point. The planet seems to change with every loop, and Selene begins experiencing vivid visions.


title: Returnal (video game)

text: Resolving to find the source of the White Shadow, Selene presses on, fighting hostile alien lifeforms and scavenging alien technology left over from the advanced, extinct alien civilization that used to reside on Atropos. As she tracks the White Shadow, Selene comes across what appears to be a replica of her childhood home. Every time she enters it, she recalls old memories and repeatedly encounters an astronaut wearing an antique space suit. Selene eventually learns that she apparently used an alien cannon to paradoxically shoot down her own ship which caused her to be stranded on Atropos.


title: Returnal (video game)

text: Eventually, Selene tracks down the source of the White Shadow. Afterwards, ASTRA is able to receive her distress call and sends a rescue ship. Selene returns to Earth and eventually dies of old age, only to reawaken back on Atropos, having looped back to the crash. Dismayed that she has failed to escape Atropos, Selene continues to explore the planet. Eventually, her search leads her to an underwater abyss below the planet's surface, where she finds a replica of an old car. From this point, the game diverges based on whether Selene fully investigated her house and recovered the car keys from it.


title: Returnal (video game)

text: "Returnal" was developed by the Finnish firm Housemarque and published by Sony Interactive Entertainment. The game was in development for more than four years. It takes advantage of the PlayStation 5's DualSense controller and Tempest Engine to support advanced haptic feedback, 3D spatial audio, and real-time ray tracing effects, enhancing the player immersion experience. With the increased processing power and inclusion of a custom solid state drive storage in the PlayStation 5, the game features reduced loading times and a wide variety of enemies, visual effects, and objects within gameplay scenes. Additionally, the game runs at 4K resolution and 60 frames per second. "Returnal"s native resolution is around 1080p. The developers used temporal upsampling to get to 1440p and then checkerboard rendering to get to 4K. "Returnal" also features an original score composed primarily by Bobby Krlic.


title: Returnal (video game)

text: "Returnal" was revealed at Sony's PlayStation 5 reveal stream on June 11, 2020. The game was exclusively developed for the PlayStation 5. The game was initially scheduled for a release on March 19, 2021. On January 28, 2021, it was announced the release date was pushed back a month to April 30, 2021. On March 25, 2021, it was announced that the game had gone gold. A free update titled "Ascension", which introduces a cooperative multiplayer mode and a new area known as the Tower of Sisyphus, was released on March 22, 2022. At The Game Awards 2022 on December 8, 2022, it was announced that the game would come to PC in "early 2023".


title: Returnal (video game)

text: "Returnal" received "generally favorable" reviews, according to review aggregator Metacritic. In a review for "IGN", Mitchell Saltzman enjoyed how the gameplay integrated with the story, writing that "It makes Selene an interesting protagonist who's in this weird repeating-but-different scenario along with us." Saltzman criticized the need to replay sections in order to reach a higher weapon proficiency, saying that it made the game "ridiculously difficult" and the only way the player could succeed was by grinding to reach a higher level. Writing for "The Guardian", Keza MacDonald gave the game a positive review, praising "Returnal" for its challenging difficulty, its rewarding combat, and engaging gameplay loop. MacDonald also praised the game for its visual and audio design, writing that "The planet looks and sounds extraordinary, each new area a distinctive biotechnological nightmare."


title: Returnal (video game)

text: The game's roguelike gameplay, which requires players to repeatedly play through levels following an in-game death, has been a divisive point among critics and players. In particular, "Returnal" has received some criticism from players for its lack of a save feature, while critics have been more mixed on its absence. Jon Bailes of "GamesRadar+" wrote that the lack of a save feature should be understood as a deliberate choice which highlights the game's themes of mortality. Bailes stated that "Selene's traumatic endeavours were in tune with my attempts to finish the game. The lack of a save feature and extra stuff to do added another dimension to the emotional experience."


title: Returnal (video game)

text: "Eurogamer"'s Chris Tapsell wrote that "checkpoints only work once per run, so you better be sure when you spend half a day's resources on one." He also noted that at one point during his time with "Returnal", "I'd paused the game while on my best-ever run, and came back not two minutes later to find my loaner PS5 in the middle of an auto-update. I lost all progress on the run, roughly a whole morning of my life. Turn auto-updates off!" Criticism of the save system from players and reviewers alike resulted in developer Housemarque issuing a statement that they were working to address the issue but did not know what form a save feature may take. In October 2021, Housemarque released Update 2.0 which allows players to "suspend cycle" to save their game during a run.


title: Returnal (video game)

text: "Returnal" sold 6,573 physical copies within its first week on sale in Japan, and was the 15th-best-selling retail game of the week in the country. Based on physical sales of the game in the UK, the game debuted at no. 2 on the sales charts for the week ending May 1, 2021. As of July 18, 2021, the game had sold over 560,000 copies.


title: Shawn Grate

text: Shawn Michael Grate (born August 8, 1976) is an American convicted serial killer, rapist, and former drifter who murdered five young women from 2006 to September 2016 in and around northern Ohio. Grate was convicted on two counts of aggravated murder on May 7, 2018, in Ashland County, pleaded guilty to two additional murders on March 1, 2019, in Richland County, and pleaded guilty to an additional murder on September 11, 2019, in Marion County.


title: Shawn Grate

text: Shawn Michael Grate was born in Marion, Ohio, on August 8, 1976, to Terry Grate and Theresa McFarland. He was said to have "lived a normal" early life, playing softball and football in his backyard and socializing with neighborhood children. Terry and Theresa married in 1974. That marriage produced two children, one in 1974 and Shawn in 1976.


title: Shawn Grate

text: In school, Grate was said to have had many problems and was held back for kindergarten and the first grade of his education. Despite these problems, he was said to be very charming and amicable, with a former female friend of his stating that "all the girls liked Shawn." Two days before Shawn's 6th birthday, his parents divorced on August 6, 1982.


title: Shawn Grate

text: When Grate was 11, his mother abandoned the family in Ohio to live with a man in Kentucky. Grate was upset with this affair and did not like Theresa's boyfriends, continuing to live with his father for the next four years. Living with his father, he attended River Valley High School, where he excelled as a baseball player but never played again after breaking his arm, which required surgery following the discovery of a tumor. Harboring murderous fantasies toward his mother from a young age, his half-sister would state that "it was a battle in the household, and that was apparent at a young age between the two of them."


title: Shawn Grate

text: According to a high school girlfriend, Grate would lay on the couch "for days" at a time before returning to normal. A court psychiatrist described Grate as "kind of a depressed kid" despite his reputation as a happy youth, stating that his condition hailed from "neglect and emotional detachment" faced in childhood. The custody of Shawn and his brother was transferred to their father, Terry, on June 28, 1994. He was arrested for grabbing his girlfriend's throat on November 24, 1994. After graduating from River Valley High School in 1995, he broke into a house in Marion County with a juvenile accomplice on October 23, 1996, to steal jewelry and money. Grate was given a felony burglary charge in January 1997 and sentenced to four years in prison before being released early in October 1997.


title: Shawn Grate

text: A grand jury indicted Grate on two counts of aggravated murder in the deaths of two women, Stacey Stanley and Elizabeth Griffith, and the kidnapping and multiple sexual assaults of an unidentified woman whose 911 call to Ashland police led to Grate's arrest on September 13, 2016. In court documents, her name has been redacted. She is being referred to as "Jane Doe." Grate was indicted on 23 counts, all first, second, or third-degree felonies; lesser charges include breaking and entering, burglary, and tampering with evidence.


title: Shawn Grate

text: Grate was represented in court by court-appointed attorney Rolf Whitney, who entered a plea of not guilty on all charges on his behalf. In a press interview Grate confessed to five murders. Grate's attorneys later filed a plea of not guilty by reason of insanity. His trial date was set for November 6, 2017, and was later delayed to April 9, 2018.


title: Shawn Grate

text: Ashland County prosecutor Christopher R. Tunnell said that given the "...depraved actions and the gruesome evidence", he would seek the death penalty.


title: Shawn Grate

text: Shawn Grate has also been charged in the deaths of his former girlfriends Candice Cunningham and Rebekah Leicy in neighboring Richland County, and has also been charged in the death of Dana Nicole Lowrey, 23, who died in 2006 and was found in 2007 in Marion County. In the second of two letters he sent to Cleveland news station WEWS (News 5 Cleveland) reporter Megan Hickey, Grate attributed his motives to "government assistance", writing that it took his victims' minds. "They were already dead, just their bodies were flopping wherever it can flop but their minds were already dead! The state took their minds. Once they started receiving their monthly checks." Grate claimed he once received a $197 food card and that he "never was able to receive any encouragement, though many bodies received 700".


title: Shawn Grate

text: After Grate gave details of the murders to two news organizations while in custody, attorneys for the defense and prosecution jointly requested and obtained a gag order preventing Grate from communicating any further with the media. On January 6, 2017, a competency hearing determined Grate fit to stand trial. An evaluation released March 6, based on a January 17 assessment to evaluate Grate's claim of insanity, declared that he was not insane at the time the crimes were committed. Grate's counsel then withdrew the plea of not guilty by reason of insanity on April 7, 2017.


title: Shawn Grate

text: In a settlement with the owner, the City of Ashland obtained ownership of the house where Grate was apprehended, two bodies were discovered, and police rescued a kidnapped woman. The city pursued a federal grant intending to demolish the house. According to Andrew Bush, assistant law director for the city of Ashland: "There is a settlement agreement among the parties that essentially obligates the Pump House to transfer all property that is the subject of this action to the city of Ashland and transfer their title thereto, provided that the city pays off the sums owed to the county for delinquent taxes and to the Muskingum Watershed District."


title: Shawn Grate

text: Grate's trial for the Ashland crimes began with two weeks of jury selection on April 9, 2018. The trial began with opening statements on April 23. On May 2, Grate, who showed no remorse pleaded guilty to 15 of the charges against him. On May 7, Grate was found guilty of murdering Stacey Stanley and Elizabeth Griffith. On June 1, Grate was sentenced to death. An initial execution date was set upon conviction for September 13, 2018, but the execution was stayed due to a pending appeal to the Ohio Supreme Court.


title: Shawn Grate

text: The defense counsel in the trial was Robert Whitney and Rolf Whitney. The prosecution team was Ashland Prosecutor Chris Tunnell, Medina County Assistant Prosecutor Michael McNamara, and Special Prosecutor Mark Weaver.


title: Shawn Grate

text: On March 1, 2019, Grate pleaded guilty to the murders of Rebekah Leicy and Candice Cunningham and was sentenced to life in prison without parole for the murder of Leicy and 17 years to life for the other charges, with the sentences running consecutively.


title: Shawn Grate

text: On September 11, 2019, Grate pleaded guilty to the murder of Dana Lowrey and was sentenced to life in prison without parole plus 16 years.


title: Shawn Grate

text: On December 10, 2020, it was reported that Grate lost his appeal against the death sentence, with the Ohio Supreme Court upholding the sentence by stating there is no mitigation or "reversible error" in Grate's case on the grounds of dismissing the appeal. Grate is scheduled to be executed on March 19, 2025. That date is when he is to be transferred to Lucasville. The method of execution is to be determined; Ohio no longer uses lethal injection as of 2020, but state law does not currently permit any other method.


title: Shawn Grate

text: While Grate slept, the victim identified by the indictment only as "Jane Doe" called 911 from the Ashland house where Grate had bound her to a bed and held her for three days, during which time he sexually assaulted her. She was safely rescued by the Ashland police. Because she was the victim of a sexual assault, police declined to reveal her identity. Grate claims he did not plan to kill her and that they were going to get married.


title: Shawn Grate

text: Having seen Shawn as something of an "older brother," the 38-year-old Doe had first met Grate in the summer of 2016 at the Ashland Salvation Army Ray & Joan Kroc Corps Community Center. There they would share lunch and go on long walks, frequently discussing the Bible and occasionally playing tennis at Brookside Park in Ashland. Despite Grate's attempts to sexually engage her, her relationship with him was described as completely platonic, refusing to exchange phone numbers.


title: Shawn Grate

text: On Sept. 11, 2016, Grate persuaded Doe to walk with him to the Ashland house on 363 Covert Court to receive some clothes he had in his possession. As Doe read the Bible in Grate's room, his friendly demeanor changed as he returned from the house's kitchen; Grate pulled the Bible out of her hand, telling her that she was not "going anywhere." Doe resisted Grate, to which he beat and strangled her.


title: Shawn Grate

text: Grate then proceeded to bind her in various "weird positions," including one that would allegedly strangle her to death as she attempted to break free. During the three-day assault, she had sustained head, bruise, and sexual orifice traumas as well as vaginal bleeding from the ordeal, claiming she'd been sexually assaulted by Grate in "every way imaginable." During the assault, Grate was also noted to have shaved a heart shape into her pubic hair, which was removed following an examination by a sexual assault forensic examiner.


title: Shawn Grate

text: Stanley's family had reported her missing the week before Grate was arrested. Her body was found at the Ashland house where Grate was arrested. She is also known as Stacy Hicks. An autopsy concluded she was strangled to death.


title: Shawn Grate

text: Elizabeth Griffith had been missing for about a month before Grate was arrested. Her body was found at the Yellow Ashland house where Grate was arrested. An autopsy concluded she was strangled to death.


title: Shawn Grate

text: Grate led police to what he claimed was Cunningham's body in neighboring Richland County on the day of his arrest. Police found the body behind a house that had previously burned down. The Richland County Sheriff's office officially confirmed that the body found was Cunningham's on November 1, 2016.


title: Shawn Grate

text: Based on information supplied by Grate, police have reopened the investigation into Leicy's death. Her body was found in March 2015, and her death was originally ruled a drug overdose. Grate says he strangled her after she stole $4.00 from him in his place of work.


title: Shawn Grate

text: Grate claims to have killed another woman who was found dead in Marion County, Ohio in 2006 and remained unidentified for 13 years. Grate has stated he believes her name was Dana. In January 2018, isotope analysis indicated she was likely from the Southern United States. The victim was identified in June 2019 by the DNA Doe Project as Dana Nicole Lowrey, 23, of Minden, Louisiana. Lowrey had two daughters aged 1 and 5 at the time of her death and was separated from her daughters’ father.


title: Electrical resistivity and conductivity

text: Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter  (rho). The SI unit of electrical resistivity is the ohm-meter (Ω⋅m). For example, if a solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is , then the resistivity of the material is .


title: Electrical resistivity and conductivity

text: Electrical conductivity or specific conductance is the reciprocal of electrical resistivity. It represents a material's ability to conduct electric current. It is commonly signified by the Greek letter  (sigma), but  (kappa) (especially in electrical engineering) and  (gamma) are sometimes used. The SI unit of electrical conductivity is siemens per metre (S/m). Resistivity and conductivity are intensive properties of materials, giving the opposition of a standard cube of material to current. Electrical resistance and conductance are corresponding extensive properties that give the opposition of a specific object to electric current.


title: Electrical resistivity and conductivity

text: In an ideal case, cross-section and physical composition of the examined material are uniform across the sample, and the electric field and current density are both parallel and constant everywhere. Many resistors and conductors do in fact have a uniform cross section with a uniform flow of electric current, and are made of a single material, so that this is a good model. (See the adjacent diagram.) When this is the case, the electrical resistivity  (Greek: rho) can be calculated by:


title: Electrical resistivity and conductivity

text: The resistivity can be expressed using the SI unit ohm metre (Ω⋅m) — "i.e." ohms multiplied by square metres (for the cross-sectional area) then divided by metres (for the length).


title: Electrical resistivity and conductivity

text: Both "resistance" and "resistivity" describe how difficult it is to make electrical current flow through a material, but unlike resistance, resistivity is an intrinsic property. This means that all pure copper wires (which have not been subjected to distortion of their crystalline structure etc.), irrespective of their shape and size, have the same resistivity, but a long, thin copper wire has a much larger resistance than a thick, short copper wire. Every material has its own characteristic resistivity. For example, rubber has a far larger resistivity than copper.


title: Electrical resistivity and conductivity

text: In a hydraulic analogy, passing current through a high-resistivity material is like pushing water through a pipe full of sand - while passing current through a low-resistivity material is like pushing water through an empty pipe. If the pipes are the same size and shape, the pipe full of sand has higher resistance to flow. Resistance, however, is not "solely" determined by the presence or absence of sand. It also depends on the length and width of the pipe: short or wide pipes have lower resistance than narrow or long pipes.


title: Electrical resistivity and conductivity

text: formula_2The resistance of a given element is proportional to the length, but inversely proportional to the cross-sectional area. For example, if  = , formula_3 = (forming a cube with perfectly conductive contacts on opposite faces), then the resistance of this element in ohms is numerically equal to the resistivity of the material it is made of in Ω⋅m.


title: Electrical resistivity and conductivity

text: For less ideal cases, such as more complicated geometry, or when the current and electric field vary in different parts of the material, it is necessary to use a more general expression in which the resistivity at a particular point is defined as the ratio of the electric field to the density of the current it creates at that point:


title: Electrical resistivity and conductivity

text: For example, rubber is a material with large and small  — because even a very large electric field in rubber makes almost no current flow through it. On the other hand, copper is a material with small and large  — because even a small electric field pulls a lot of current through it.


title: Electrical resistivity and conductivity

text: As shown below, this expression simplifies to a single number when the electric field and current density are constant in the material.


title: Electrical resistivity and conductivity

text: When the resistivity of a material has a directional component, the most general definition of resistivity must be used. It starts from the tensor-vector form of Ohm's law, which relates the electric field inside a material to the electric current flow. This equation is completely general, meaning it is valid in all cases, including those mentioned above. However, this definition is the most complicated, so it is only directly used in anisotropic cases, where the more simple definitions cannot be applied. If the material is not anisotropic, it is safe to ignore the tensor-vector definition, and use a simpler expression instead.


title: Electrical resistivity and conductivity

text: Here, anisotropic means that the material has different properties in different directions. For example, a crystal of graphite consists microscopically of a stack of sheets, and current flows very easily through each sheet, but much less easily from one sheet to the adjacent one. In such cases, the current does not flow in exactly the same direction as the electric field. Thus, the appropriate equations are generalized to the three-dimensional tensor form:


title: Electrical resistivity and conductivity

text: where the conductivity and resistivity are rank-2 tensors, and electric field and current density are vectors. These tensors can be represented by 3×3 matrices, the vectors with 3×1 matrices, with matrix multiplication used on the right side of these equations. In matrix form, the resistivity relation is given by:


title: Electrical resistivity and conductivity

text: Since the choice of the coordinate system is free, the usual convention is to simplify the expression by choosing an -axis parallel to the current direction, so . This leaves:


title: Electrical resistivity and conductivity

text: Looking at the two expressions, formula_17 and formula_18 are the matrix inverse of each other. However, in the most general case, the individual matrix elements are not necessarily reciprocals of one another; for example, may not be equal to . This can be seen in the Hall effect, where formula_19 is nonzero. In the Hall effect, due to rotational invariance about the -axis, formula_20 and formula_21, so the relation between resistivity and conductivity simplifies to:


title: Electrical resistivity and conductivity

text: If the electric field is parallel to the applied current, formula_19 and formula_24 are zero. When they are zero, one number, formula_25, is enough to describe the electrical resistivity. It is then written as simply formula_26, and this reduces to the simpler expression.


title: Electrical resistivity and conductivity

text: According to elementary quantum mechanics, an electron in an atom or crystal can only have certain precise energy levels; energies between these levels are impossible. When a large number of such allowed levels have close-spaced energy values – i.e. have energies that differ only minutely – those close energy levels in combination are called an "energy band". There can be many such energy bands in a material, depending on the atomic number of the constituent atoms and their distribution within the crystal.


title: Electrical resistivity and conductivity

text: The material's electrons seek to minimize the total energy in the material by settling into low energy states; however, the Pauli exclusion principle means that only one can exist in each such state. So the electrons "fill up" the band structure starting from the bottom. The characteristic energy level up to which the electrons have filled is called the Fermi level. The position of the Fermi level with respect to the band structure is very important for electrical conduction: Only electrons in energy levels near or above the Fermi level are free to move within the broader material structure, since the electrons can easily jump among the partially occupied states in that region. In contrast, the low energy states are completely filled with a fixed limit on the number of electrons at all times, and the high energy states are empty of electrons at all times.


title: Electrical resistivity and conductivity

text: Electric current consists of a flow of electrons. In metals there are many electron energy levels near the Fermi level, so there are many electrons available to move. This is what causes the high electronic conductivity of metals.


title: Electrical resistivity and conductivity

text: An important part of band theory is that there may be forbidden bands of energy: energy intervals that contain no energy levels. In insulators and semiconductors, the number of electrons is just the right amount to fill a certain integer number of low energy bands, exactly to the boundary. In this case, the Fermi level falls within a band gap. Since there are no available states near the Fermi level, and the electrons are not freely movable, the electronic conductivity is very low.


title: Electrical resistivity and conductivity

text: A metal consists of a lattice of atoms, each with an outer shell of electrons that freely dissociate from their parent atoms and travel through the lattice. This is also known as a positive ionic lattice. This 'sea' of dissociable electrons allows the metal to conduct electric current. When an electrical potential difference (a voltage) is applied across the metal, the resulting electric field causes electrons to drift towards the positive terminal. The actual drift velocity of electrons is typically small, on the order of magnitude of meters per hour. However, due to the sheer number of moving electrons, even a slow drift velocity results in a large current density. The mechanism is similar to transfer of momentum of balls in a Newton's cradle but the rapid propagation of an electric energy along a wire is not due to the mechanical forces, but the propagation of an energy-carrying electromagnetic field guided by the wire.


title: Electrical resistivity and conductivity

text: Most metals have electrical resistance. In simpler models (non quantum mechanical models) this can be explained by replacing electrons and the crystal lattice by a wave-like structure. When the electron wave travels through the lattice, the waves interfere, which causes resistance. The more regular the lattice is, the less disturbance happens and thus the less resistance. The amount of resistance is thus mainly caused by two factors. First, it is caused by the temperature and thus amount of vibration of the crystal lattice. Higher temperatures cause bigger vibrations, which act as irregularities in the lattice. Second, the purity of the metal is relevant as a mixture of different ions is also an irregularity. The small decrease in conductivity on melting of pure metals is due to the loss of long range crystalline order. The short range order remains and strong correlation between positions of ions results in coherence between waves diffracted by adjacent ions.


title: Electrical resistivity and conductivity

text: In metals, the Fermi level lies in the conduction band (see Band Theory, above) giving rise to free conduction electrons. However, in semiconductors the position of the Fermi level is within the band gap, about halfway between the conduction band minimum (the bottom of the first band of unfilled electron energy levels) and the valence band maximum (the top of the band below the conduction band, of filled electron energy levels). That applies for intrinsic (undoped) semiconductors. This means that at absolute zero temperature, there would be no free conduction electrons, and the resistance is infinite. However, the resistance decreases as the charge carrier density (i.e., without introducing further complications, the density of electrons) in the conduction band increases. In extrinsic (doped) semiconductors, dopant atoms increase the majority charge carrier concentration by donating electrons to the conduction band or producing holes in the valence band. (A "hole" is a position where an electron is missing; such holes can behave in a similar way to electrons.) For both types of donor or acceptor atoms, increasing dopant density reduces resistance. Hence, highly doped semiconductors behave metallically. At very high temperatures, the contribution of thermally generated carriers dominates over the contribution from dopant atoms, and the resistance decreases exponentially with temperature.


title: Electrical resistivity and conductivity

text: In electrolytes, electrical conduction happens not by band electrons or holes, but by full atomic species (ions) traveling, each carrying an electrical charge. The resistivity of ionic solutions (electrolytes) varies tremendously with concentration – while distilled water is almost an insulator, salt water is a reasonable electrical conductor. Conduction in ionic liquids is also controlled by the movement of ions, but here we are talking about molten salts rather than solvated ions. In biological membranes, currents are carried by ionic salts. Small holes in cell membranes, called ion channels, are selective to specific ions and determine the membrane resistance.


title: Electrical resistivity and conductivity

text: The concentration of ions in a liquid ("e.g.", in an aqueous solution) depends on the degree of dissociation of the dissolved substance, characterized by a dissociation coefficient formula_27, which is the ratio of the concentration of ions formula_28 to the concentration of molecules of the dissolved substance formula_29:


title: Electrical resistivity and conductivity

text: where formula_33: module of the ion charge, formula_34 and formula_35: mobility of positively and negatively charged ions, formula_29: concentration of molecules of the dissolved substance, formula_27: the coefficient of dissociation.


title: Electrical resistivity and conductivity

text: The electrical resistivity of a metallic conductor decreases gradually as temperature is lowered. In normal (that is, non-superconducting) conductors, such as copper or silver, this decrease is limited by impurities and other defects. Even near absolute zero, a real sample of a normal conductor shows some resistance. In a superconductor, the resistance drops abruptly to zero when the material is cooled below its critical temperature. In a normal conductor, the current is driven by a voltage gradient, whereas in a superconductor, there is no voltage gradient and the current is instead related to the phase gradient of the superconducting order parameter. A consequence of this is that an electric current flowing in a loop of superconducting wire can persist indefinitely with no power source.


title: Electrical resistivity and conductivity

text: In a class of superconductors known as type II superconductors, including all known high-temperature superconductors, an extremely low but nonzero resistivity appears at temperatures not too far below the nominal superconducting transition when an electric current is applied in conjunction with a strong magnetic field, which may be caused by the electric current. This is due to the motion of magnetic vortices in the electronic superfluid, which dissipates some of the energy carried by the current. The resistance due to this effect is tiny compared with that of non-superconducting materials, but must be taken into account in sensitive experiments. However, as the temperature decreases far enough below the nominal superconducting transition, these vortices can become frozen so that the resistance of the material becomes truly zero.


title: Electrical resistivity and conductivity

text: The potential as it exists on average in the space between charged particles, independent of the question of how it can be measured, is called the "plasma potential", or "space potential". If an electrode is inserted into a plasma, its potential generally lies considerably below the plasma potential, due to what is termed a Debye sheath. The good electrical conductivity of plasmas makes their electric fields very small. This results in the important concept of "quasineutrality", which says the density of negative charges is approximately equal to the density of positive charges over large volumes of the plasma (), but on the scale of the Debye length there can be charge imbalance. In the special case that "double layers" are formed, the charge separation can extend some tens of Debye lengths.


title: Electrical resistivity and conductivity

text: The magnitude of the potentials and electric fields must be determined by means other than simply finding the net charge density. A common example is to assume that the electrons satisfy the Boltzmann relation:


title: Electrical resistivity and conductivity

text: It is possible to produce a plasma that is not quasineutral. An electron beam, for example, has only negative charges. The density of a non-neutral plasma must generally be very low, or it must be very small. Otherwise, the repulsive electrostatic force dissipates it.


title: Electrical resistivity and conductivity

text: In astrophysical plasmas, Debye screening prevents electric fields from directly affecting the plasma over large distances, i.e., greater than the Debye length. However, the existence of charged particles causes the plasma to generate, and be affected by, magnetic fields. This can and does cause extremely complex behavior, such as the generation of plasma double layers, an object that separates charge over a few tens of Debye lengths. The dynamics of plasmas interacting with external and self-generated magnetic fields are studied in the academic discipline of magnetohydrodynamics.


title: Electrical resistivity and conductivity

text: Plasma is often called the "fourth state of matter" after solid, liquids and gases. It is distinct from these and other lower-energy states of matter. Although it is closely related to the gas phase in that it also has no definite form or volume, it differs in a number of ways, including the following:


title: Electrical resistivity and conductivity

text: The degree of semiconductors doping makes a large difference in conductivity. To a point, more doping leads to higher conductivity. The conductivity of a water/aqueous solution is highly dependent on its concentration of dissolved salts, and other chemical species that ionize in the solution. Electrical conductivity of water samples is used as an indicator of how salt-free, ion-free, or impurity-free the sample is; the purer the water, the lower the conductivity (the higher the resistivity). Conductivity measurements in water are often reported as "specific conductance", relative to the conductivity of pure water at . An EC meter is normally used to measure conductivity in a solution. A rough summary is as follows:


title: Electrical resistivity and conductivity

text: This table shows the resistivity (), conductivity and temperature coefficient of various materials at .


title: Electrical resistivity and conductivity

text: The effective temperature coefficient varies with temperature and purity level of the material. The 20 °C value is only an approximation when used at other temperatures. For example, the coefficient becomes lower at higher temperatures for copper, and the value 0.00427 is commonly specified at .


title: Electrical resistivity and conductivity

text: The extremely low resistivity (high conductivity) of silver is characteristic of metals. George Gamow tidily summed up the nature of the metals' dealings with electrons in his popular science book "One, Two, Three...Infinity" (1947):


title: Electrical resistivity and conductivity

text: Wood is widely regarded as an extremely good insulator, but its resistivity is sensitively dependent on moisture content, with damp wood being a factor of at least worse insulator than oven-dry. In any case, a sufficiently high voltage – such as that in lightning strikes or some high-tension power lines – can lead to insulation breakdown and electrocution risk even with apparently dry wood.


title: Electrical resistivity and conductivity

text: The electrical resistivity of most materials changes with temperature. If the temperature does not vary too much, a linear approximation is typically used:


title: Electrical resistivity and conductivity

text: where formula_27 is called the "temperature coefficient of resistivity", formula_42 is a fixed reference temperature (usually room temperature), and formula_43 is the resistivity at temperature formula_42. The parameter formula_27 is an empirical parameter fitted from measurement data. Because the linear approximation is only an approximation, formula_27 is different for different reference temperatures. For this reason it is usual to specify the temperature that formula_27 was measured at with a suffix, such as formula_48, and the relationship only holds in a range of temperatures around the reference. When the temperature varies over a large temperature range, the linear approximation is inadequate and a more detailed analysis and understanding should be used.


title: Electrical resistivity and conductivity

text: In general, electrical resistivity of metals increases with temperature. Electron–phonon interactions can play a key role. At high temperatures, the resistance of a metal increases linearly with temperature. As the temperature of a metal is reduced, the temperature dependence of resistivity follows a power law function of temperature. Mathematically the temperature dependence of the resistivity of a metal can be approximated through the Bloch–Grüneisen formula:


title: Electrical resistivity and conductivity

text: where formula_50 is the residual resistivity due to defect scattering, A is a constant that depends on the velocity of electrons at the Fermi surface, the Debye radius and the number density of electrons in the metal. formula_51 is the Debye temperature as obtained from resistivity measurements and matches very closely with the values of Debye temperature obtained from specific heat measurements. n is an integer that depends upon the nature of interaction:


title: Electrical resistivity and conductivity

text: The Bloch–Grüneisen formula is an approximation obtained assuming that the studied metal has spherical Fermi surface inscribed within the first Brillouin zone and a Debye phonon spectrum.


title: Electrical resistivity and conductivity

text: If more than one source of scattering is simultaneously present, Matthiessen's rule (first formulated by Augustus Matthiessen in the 1860s) states that the total resistance can be approximated by adding up several different terms, each with the appropriate value of .


title: Electrical resistivity and conductivity

text: As the temperature of the metal is sufficiently reduced (so as to 'freeze' all the phonons), the resistivity usually reaches a constant value, known as the residual resistivity. This value depends not only on the type of metal, but on its purity and thermal history. The value of the residual resistivity of a metal is decided by its impurity concentration. Some materials lose all electrical resistivity at sufficiently low temperatures, due to an effect known as superconductivity.


title: Electrical resistivity and conductivity

text: An investigation of the low-temperature resistivity of metals was the motivation to Heike Kamerlingh Onnes's experiments that led in 1911 to discovery of superconductivity. For details see History of superconductivity.


title: Electrical resistivity and conductivity

text: The Wiedemann–Franz law states that the coefficient of electrical conductivity of metals at normal temperatures is inversely proportional to the temperature:


title: Electrical resistivity and conductivity

text: where formula_54 is the thermal conductivity of the metal, formula_55 is the Boltzmann constant, formula_56 is the electron charge, formula_57 is temperature, and formula_31 is the electrical conductivity coefficient.


title: Electrical resistivity and conductivity

text: In general, intrinsic semiconductor resistivity decreases with increasing temperature. The electrons are bumped to the conduction energy band by thermal energy, where they flow freely, and in doing so leave behind holes in the valence band, which also flow freely. The electric resistance of a typical intrinsic (non doped) semiconductor decreases exponentially with temperature:


title: Electrical resistivity and conductivity

text: An even better approximation of the temperature dependence of the resistivity of a semiconductor is given by the Steinhart–Hart equation:


title: Electrical resistivity and conductivity

text: Extrinsic (doped) semiconductors have a far more complicated temperature profile. As temperature increases starting from absolute zero they first decrease steeply in resistance as the carriers leave the donors or acceptors. After most of the donors or acceptors have lost their carriers, the resistance starts to increase again slightly due to the reducing mobility of carriers (much as in a metal). At higher temperatures, they behave like intrinsic semiconductors as the carriers from the donors/acceptors become insignificant compared to the thermally generated carriers.


title: Electrical resistivity and conductivity

text: In non-crystalline semiconductors, conduction can occur by charges quantum tunnelling from one localised site to another. This is known as variable range hopping and has the characteristic form of


title: Electrical resistivity and conductivity

text: When analyzing the response of materials to alternating electric fields (dielectric spectroscopy), in applications such as electrical impedance tomography, it is convenient to replace resistivity with a complex quantity called impedivity (in analogy to electrical impedance). Impedivity is the sum of a real component, the resistivity, and an imaginary component, the reactivity (in analogy to reactance). The magnitude of impedivity is the square root of sum of squares of magnitudes of resistivity and reactivity.


title: Electrical resistivity and conductivity

text: Conversely, in such cases the conductivity must be expressed as a complex number (or even as a matrix of complex numbers, in the case of anisotropic materials) called the "admittivity". Admittivity is the sum of a real component called the conductivity and an imaginary component called the susceptivity.


title: Electrical resistivity and conductivity

text: An alternative description of the response to alternating currents uses a real (but frequency-dependent) conductivity, along with a real permittivity. The larger the conductivity is, the more quickly the alternating-current signal is absorbed by the material (i.e., the more opaque the material is). For details, see Mathematical descriptions of opacity.


title: Electrical resistivity and conductivity

text: Even if the material's resistivity is known, calculating the resistance of something made from it may, in some cases, be much more complicated than the formula formula_62 above. One example is spreading resistance profiling, where the material is inhomogeneous (different resistivity in different places), and the exact paths of current flow are not obvious.


title: Electrical resistivity and conductivity

text: where and are now vector fields. This equation, along with the continuity equation for and the Poisson's equation for , form a set of partial differential equations. In special cases, an exact or approximate solution to these equations can be worked out by hand, but for very accurate answers in complex cases, computer methods like finite element analysis may be required.


title: Electrical resistivity and conductivity

text: In some applications where the weight of an item is very important, the product of resistivity and density is more important than absolute low resistivity – it is often possible to make the conductor thicker to make up for a higher resistivity; and then a low-resistivity-density-product material (or equivalently a high conductivity-to-density ratio) is desirable. For example, for long-distance overhead power lines, aluminium is frequently used rather than copper (Cu) because it is lighter for the same conductance.


title: Electrical resistivity and conductivity

text: Silver, although it is the least resistive metal known, has a high density and performs similarly to copper by this measure, but is much more expensive. Calcium and the alkali metals have the best resistivity-density products, but are rarely used for conductors due to their high reactivity with water and oxygen (and lack of physical strength). Aluminium is far more stable. Toxicity excludes the choice of beryllium. (Pure beryllium is also brittle.) Thus, aluminium is usually the metal of choice when the weight or cost of a conductor is the driving consideration.


title: Gary Payton II

text: Gary Dwayne Payton II (born December 1, 1992) is an American professional basketball player for the Portland Trail Blazers of the National Basketball Association (NBA). As a junior and senior playing college basketball for the Oregon State Beavers, Payton was named first-team All-Pac-12 as well as Pac-12 Defensive Player of the Year. He won an NBA championship with the Golden State Warriors in 2022.


title: Gary Payton II

text: He is the son of Hall of Famer Gary Payton. He is sometimes called "Young Glove" in reference to his father's nickname, "the Glove." His other nickname is “the Mitten”, but he prefers Young Glove. He is also commonly referred to as "GP2".


title: Gary Payton II

text: Payton was born in Seattle to Monique and Gary Payton, while his father was a member of the Seattle SuperSonics. He attended Spring Valley High School where he lettered two years in basketball and one year in swimming before graduating in 2011. He then enrolled at Westwind Preparatory Academy for the 2011–12 season.


title: Gary Payton II

text: Payton played two seasons at Salt Lake Community College in Salt Lake City, Utah. He averaged 9.4 points, 6.2 rebounds, 3.7 assists, and 1.9 steals per game as a freshman (2012–13) and led the Bruins to a 29–5 overall record and 14–1 mark in the Scenic West Athletic Conference (SWAC), where they won the Region 18 Championship and outright SWAC title in 2013. Payton was named First Team All-SWAC and made Region 18 All-Tournament Team as a freshman. In his sophomore year, he averaged 14.1 points, 7.9 rebounds, 3.8 assists, and 1.9 steals per game, earning him Second Team NJCAA Division I All-American honors, and was voted 2014 Region 18 Co-Player of the Year and Region 18 Tournament Most Valuable Player. The Bruins finished with a 27–7 overall record and won their second consecutive Region 18 Championship.


title: Gary Payton II

text: During Payton's sophomore season at Salt Lake CC he signed a letter of intent to play for his father's alma mater Oregon State under coach Craig Robinson. Robinson was fired before the start of the 2014–15 basketball season and was replaced by University of Montana head coach Wayne Tinkle. Having lost their top five scorers from the previous season, Pac-12 coaches picked Oregon State to finish 12th in the 2014–15 season. Instead, the up-tempo Beavers finished 7th with a 4–1 record against the conference's top three teams, Arizona, Oregon and Utah. In their game against Grambling State, Payton recorded 10 points, 12 rebounds and 10 assists, becoming only the second Beaver ever with a triple-double in a game. His father, Hall of Famer Gary Payton, is the other Beaver with a triple-double when he had 20 points, 14 rebounds and 11 assists against the University of Portland in 1988. Following a home sweep of the Los Angeles schools Payton was named the January 26, 2015 Pac-12 Conference Player of the Week. During his first season at Oregon State Payton led his team in multiple categories: scoring, rebounds, and steals. On March 9, 2015, Pac-12 coaches voted Payton to the All-Pac-12 First Team, All-Pac-12 Defensive Team and named him the Pac-12 Defensive Player of the Year.


title: Gary Payton II

text: On February 1, 2016, he was named one of 10 finalists for the Bob Cousy Award for top point guard of the year. He was named to the 35-man mid-season watchlist for the Naismith Player of the Year on February 11.


title: Gary Payton II

text: After going undrafted in the 2016 NBA draft, Payton II joined the Houston Rockets for the 2016 NBA Summer League. On September 23, 2016, he signed with the Rockets, but was later waived on October 24 after appearing in six preseason games. On October 31, 2016, he was acquired by the Rio Grande Valley Vipers of the NBA Development League as an affiliate player of the Rockets. On December 3, 2016, he scored 51 points on 20-of-29 shooting to go with 11 rebounds in a 140–125 win over the Los Angeles D-Fenders.


title: Gary Payton II

text: On April 2, 2017, Payton II signed with the Milwaukee Bucks. He made his debut for the Bucks that night, scoring five points in nine minutes off the bench in a 109–105 loss to the Dallas Mavericks. Payton II was waived on October 14 as one of the team's final 2017–18 preseason roster cuts. On October 17, 2017, Payton II was given a two-way contract with the Bucks via their NBA G League affiliate the Wisconsin Herd, meaning he would officially return to Milwaukee for the start of the season. Payton II would have his first start in the NBA on November 22, 2017, against the Phoenix Suns, playing as the starting small forward for the Bucks that night due to team injuries. While he would end the night early due to an injury of his own, the Bucks would win that night in overtime. On December 13, Payton II was waived from the Bucks in favor of Sean Kilpatrick.


title: Gary Payton II

text: On January 15, 2018, the Los Angeles Lakers signed Payton II to a two-way contract. Throughout the rest of the season, he split his playing time between the Los Angeles Lakers and their NBA G League affiliate, the South Bay Lakers. On the final game of the season, Payton scored a career-high 25 points and also posted a career-high 12 rebounds against the Los Angeles Clippers. He was the last Laker to wear number #23 before LeBron James.


title: Gary Payton II

text: On September 4, 2018, Payton signed a training camp contract with the Portland Trail Blazers. On October 13, 2018, Payton was waived by the Trail Blazers.


title: Gary Payton II

text: On December 12, 2018, the Rio Grande Valley Vipers of the NBA G League announced via Twitter that they had re-acquired Payton.


title: Gary Payton II

text: On January 21, 2019, Payton signed with the Washington Wizards on a 10-day contract, and Payton made his debut for the Wizards on January 22 in a 101–87 win over the Detroit Pistons, but was not offered a second 10-day contract.


title: Gary Payton II

text: On October 24, 2019, the Canton Charge acquired the returning right from Rio Grande Valley Vipers for Payton in exchange for Jaron Blossomgame. Two days later on October 26, 2019, Payton was traded to the South Bay Lakers for Sheldon Mac and Robert Heyer. Two days later on October 28, 2019, Payton was added to the training camp roster of the South Bay Lakers. On November 4, 2019, Payton was included in the opening night roster of the South Bay Lakers.


title: Gary Payton II

text: On December 23, 2019, Payton signed with the Washington Wizards. On July 9, 2020, he tested positive for COVID-19.


title: Gary Payton II

text: On January 11, 2021, Payton was selected 15th overall by the Raptors 905 in the first 2021 NBA G League draft, where he averaged 10.8 points on 55.5 percent shooting from the field, 5.6 rebounds, 2.6 assists and 2.54 steals in 21.9 minutes per game. At the end of the shortened single-site season in Orlando, he was named the 2021 Defensive Player of the Year.


title: Gary Payton II

text: On April 8, 2021, Payton signed a 10-day contract with the Golden State Warriors. On April 19, he signed a second 10-day contract and on May 16, he was signed for the rest of the season and the next season.


title: Gary Payton II

text: Payton was waived shortly before the start of the 2021–22 NBA season, but was re-signed by the Warriors on October 19 after he cleared waivers. Payton had a breakout season and started the first two games of the Western Conference semifinals against the Memphis Grizzlies. In Game 2, he fractured his left elbow when he went up for a fast-break layup but fell hard after the Grizzlies' Dillon Brooks chased him down and hit him in the head while he was in the air.


title: Gary Payton II

text: In Game 5 of the Finals, Payton posted 15 points, five rebounds and three steals in a 104–94 win over the Boston Celtics. The Warriors went on to win Game 6, where Payton played a major defensive role, and Payton won his first NBA championship. He and his father became the fifth father-son duo to win an NBA title, with one of the other pairs including Payton's teammate Klay Thompson.


title: SIM card

text: A SIM card (full form Subscriber Identity Module or Subscriber Identification Module) is an integrated circuit (IC) intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers). Technically the actual physical card is known as a universal integrated circuit card (UICC); this smart card is usually made of PVC with embedded contacts and semiconductors, with the SIM as its primary component. In practise the term "SIM card" refers to the entire unit and not simply the IC.


title: SIM card

text: A SIM contains a unique serial number (ICCID), international mobile subscriber identity (IMSI) number, security authentication and ciphering information, temporary information related to the local network, a list of the services the user has access to, and two passwords: a personal identification number (PIN) for ordinary use, and a personal unblocking key (PUK) for PIN unlocking. In Europe, the serial SIM number (SSN) is also sometimes accompanied by an international article number (IAN) or a European article number (EAN) required when registering online for the subscription of a prepaid card. It is also possible to store contact information on many SIM cards.


title: SIM card

text: SIMs are always used on GSM phones; for CDMA phones, they are needed only for LTE-capable handsets. SIM cards can also be used in satellite phones, smart watches, computers, or cameras.


title: SIM card

text: The first SIM cards were the size of credit and bank cards; sizes were reduced several times over the years, usually keeping electrical contacts the same, so that a larger card could be cut down to a smaller size.


title: SIM card

text: SIMs are transferable between different mobile devices by removing the card itself. eSIM is replacing physical SIM cards in some domains, including cellular telephony. eSIM uses a software-based SIM embedded into an unremovable eUICC.


title: SIM card

text: The SIM card is a type of smart card, the basis for which is the silicon integrated circuit (IC) chip. The idea of incorporating a silicon IC chip onto a plastic card originates from the late 1960s. Smart cards have since used MOS integrated circuit chips, along with MOS memory technologies such as flash memory and EEPROM (electrically erasable programmable read-only memory).


title: SIM card

text: The SIM was initially specified by the European Telecommunications Standards Institute in the specification with the number TS 11.11. This specification describes the physical and logical behaviour of the SIM. With the development of UMTS, the specification work was partially transferred to 3GPP. 3GPP is now responsible for the further development of applications like SIM (TS 51.011) and USIM (TS 31.102) and ETSI for the further development of the physical card UICC.


title: SIM card

text: The first SIM card was developed in 1991 by Munich smart-card maker Giesecke & Devrient, who sold the first 300 SIM cards to the Finnish wireless network operator Radiolinja.


title: SIM card

text: Today, SIM cards are ubiquitous, allowing over 7 billion devices to connect to cellular networks around the world. According to the International Card Manufacturers Association (ICMA), there were 5.4 billion SIM cards manufactured globally in 2016 creating over $6.5 billion in revenue for traditional SIM card vendors. The rise of cellular IoT and 5G networks is predicted to drive the growth of the addressable market for SIM card manufacturers to over 20 billion cellular devices by 2020. The introduction of embedded-SIM (eSIM) and remote SIM provisioning (RSP) from the GSMA may disrupt the traditional SIM card ecosystem with the entrance of new players specializing in "digital" SIM card provisioning and other value-added services for mobile network operators.


title: SIM card

text: There are three operating voltages for SIM cards: , and (ISO/IEC 7816-3 classes A, B and C, respectively). The operating voltage of the majority of SIM cards launched before 1998 was . SIM cards produced subsequently are compatible with and . Modern cards support , and .


title: SIM card

text: Modern SIM cards allow applications to load when the SIM is in use by the subscriber. These applications communicate with the handset or a server using SIM Application Toolkit, which was initially specified by 3GPP in TS 11.14. (There is an identical ETSI specification with different numbering.) ETSI and 3GPP maintain the SIM specifications. The main specifications are: ETSI TS 102 223 (the toolkit for smart cards), ETSI TS 102 241 (API), ETSI TS 102 588 (application invocation), and ETSI TS 131 111 (toolkit for more SIM-likes). SIM toolkit applications were initially written in native code using proprietary APIs. To provide interoperability of the applications, ETSI chose Java Card. A multi-company collaboration called GlobalPlatform defines some extensions on the cards, with additional APIs and features like more cryptographic security and RFID contactless use added.


title: SIM card

text: SIM cards store network-specific information used to authenticate and identify subscribers on the network. The most important of these are the ICCID, IMSI, authentication key (K), local area identity (LAI) and operator-specific emergency number. The SIM also stores other carrier-specific data such as the SMSC (Short Message service center) number, service provider name (SPN), service dialling numbers (SDN), advice-of-charge parameters and value-added service (VAS) applications. (Refer to GSM 11.11.)


title: SIM card

text: SIM cards can come in various data capacities, from to at least . All can store a maximum of 250 contacts on the SIM, but while the has room for 33 mobile network codes (MNCs) or "network identifiers", the version has room for 80 MNCs. This is used by network operators to store data on preferred networks, mostly used when the SIM is not in its home network but is roaming. The network operator that issued the SIM card can use this to have a phone connect to a preferred network that is more economic for the provider instead of having to pay the network operator that the phone discovered first. This does not mean that a phone containing this SIM card can connect to a maximum of only 33 or 80 networks, instead it means that the SIM card issuer can specify only up to that number of preferred networks. If a SIM is outside these preferred networks, it uses the first or best available network.


title: SIM card

text: Each SIM is internationally identified by its integrated circuit card identifier (ICCID). ICCID is the identifier of the actual SIM card itself: i.e. an identifier for the SIM chip. Nowadays ICCID numbers are also used to identify eSIM profiles, and not only physical SIM cards. ICCIDs are stored in the SIM cards and are also engraved or printed on the SIM card body during a process called personalisation. The ICCID is defined by the ITU-T recommendation E.118 as the "primary account number". Its layout is based on ISO/IEC 7812. According to E.118, the number can be up to 19 digits long, including a single check digit calculated using the Luhn algorithm. However, the GSM Phase 1 defined the ICCID length as an opaque data field, 10 octets (20 digits) in length, whose structure is specific to a mobile network operator.


title: SIM card

text: With the GSM Phase 1 specification using 10 octets into which ICCID is stored as packed BCD, the data field has room for 20 digits with hexadecimal digit "F" being used as filler when necessary.


title: SIM card

text: In practice, this means that on GSM SIM cards there are 20-digit (19+1) and 19-digit (18+1) ICCIDs in use, depending upon the issuer. However, a single issuer always uses the same size for its ICCIDs.


title: SIM card

text: To confuse matters more, SIM factories seem to have varying ways of delivering electronic copies of SIM personalization datasets. Some datasets are without the ICCID checksum digit, others are with the digit.


title: SIM card

text: As required by E.118, the ITU-T updates a list of all current internationally assigned IIN codes in its Operational Bulletins which are published twice a month (the last as of January 2019 was No. 1163 from 1 January 2019). ITU-T also publishes complete lists: as of January 2019, the list issued on 1 December 2018 was current, having all issuer identifier numbers before 1 December 2018.


title: SIM card

text: SIM cards are identified on their individual operator networks by a unique international mobile subscriber identity (IMSI). Mobile network operators connect mobile phone calls and communicate with their market SIM cards using their IMSIs. The format is:


title: SIM card

text: The K is a 128-bit value used in authenticating the SIMs on a GSM mobile network (for USIM network, the K is still needed but other parameters are also needed). Each SIM holds a unique K assigned to it by the operator during the personalisation process. The K is also stored in a database (termed authentication center or AuC) on the carrier's network.


title: SIM card

text: The SIM card is designed to prevent someone from getting the K by using the smart-card interface. Instead, the SIM card provides a function, "Run GSM Algorithm", that the phone uses to pass data to the SIM card to be signed with the K. This, by design, makes using the SIM card mandatory unless the K can be extracted from the SIM card, or the carrier is willing to reveal the K. In practice, the GSM cryptographic algorithm for computing a signed response (SRES_1/SRES_2: see steps 3 and 4, below) from the K has certain vulnerabilities that can allow the extraction of the K from a SIM card and the making of a duplicate SIM card.


title: SIM card

text: The SIM stores network state information, which is received from the location area identity (LAI). Operator networks are divided into location areas, each having a unique LAI number. When the device changes locations, it stores the new LAI to the SIM and sends it back to the operator network with its new location. If the device is power cycled, it takes data off the SIM, and searches for the prior LAI.


title: SIM card

text: Most SIM cards store a number of SMS messages and phone book contacts. It stores the contacts in simple "name and number" pairs. Entries that contain multiple phone numbers and additional phone numbers are usually not stored on the SIM card. When a user tries to copy such entries to a SIM, the handset's software breaks them into multiple entries, discarding information that is not a phone number. The number of contacts and messages stored depends on the SIM; early models stored as few as five messages and 20 contacts, while modern SIM cards can usually store over 250 contacts.


title: SIM card

text: SIM cards have been made smaller over the years; functionality is independent of format. Full-size SIM was followed by mini-SIM, micro-SIM, and nano-SIM. SIM cards are also made to embed in devices.


title: SIM card

text: The "full-size SIM" (or 1FF, 1st form factor) was the first form factor to appear. It was the size of a credit card (85.60 mm × 53.98 mm × 0.76 mm). Later smaller SIMs are often supplied embedded in a full-size card from which they can be removed.


title: SIM card

text: The "mini-SIM" (or 2FF) card has the same contact arrangement as the full-size SIM card and is normally supplied within a full-size card carrier, attached by a number of linking pieces. This arrangement (defined in ISO/IEC 7810 as ID-1/000) lets such a card be used in a device that requires a full-size card or in a device that requires a mini-SIM card, after breaking the linking pieces. As the full-size SIM is no longer used, some suppliers refer to the mini-SIM as a "standard SIM" or "regular SIM".


title: SIM card

text: The "micro-SIM" (or 3FF) card has the same thickness and contact arrangements, but reduced length and width as shown in the table above.


title: SIM card

text: The micro-SIM was introduced by the European Telecommunications Standards Institute (ETSI) along with SCP, 3GPP (UTRAN/GERAN), 3GPP2 (CDMA2000), ARIB, GSM Association (GSMA SCaG and GSMNA), GlobalPlatform, Liberty Alliance, and the Open Mobile Alliance (OMA) for the purpose of fitting into devices too small for a mini-SIM card.


title: SIM card

text: The form factor was mentioned in the December 1998 3GPP SMG9 UMTS Working Party, which is the standards-setting body for GSM SIM cards, and the form factor was agreed upon in late 2003.


title: SIM card

text: The micro-SIM was designed for backward compatibility. The major issue for backward compatibility was the contact area of the chip. Retaining the same contact area makes the micro-SIM compatible with the prior, larger SIM readers through the use of plastic cutout surrounds. The SIM was also designed to run at the same speed (5 MHz) as the prior version. The same size and positions of pins resulted in numerous "How-to" tutorials and YouTube videos with detailed instructions how to cut a mini-SIM card to micro-SIM size.


title: SIM card

text: Micro-SIM cards were introduced by various mobile service providers for the launch of the original iPad, and later for smartphones, from April 2010. The iPhone 4 was the first smartphone to use a micro-SIM card in June 2010, followed by many others.


title: SIM card

text: The "nano-SIM" (or 4FF) card was introduced on 11 October 2012, when mobile service providers in various countries started to supply it for phones that supported the format. The nano-SIM measures and reduces the previous format to the contact area while maintaining the existing contact arrangements. A small rim of isolating material is left around the contact area to avoid short circuits with the socket. The nano-SIM is thick, compared to the of its predecessors. 4FF can be put into adapters for use with devices designed for 2FF or 3FF SIMs, and is made thinner for that purpose, and telephone companies give due warning about this.


title: SIM card

text: The iPhone 5, released in September 2012, was the first device to use a nano-SIM card, followed by other handsets.


title: SIM card

text: In July 2013, Karsten Nohl, a security researcher from SRLabs, described vulnerabilities in some SIM cards that supported DES, which, despite its age, is still used by some operators. The attack could lead to the phone being remotely cloned or let someone steal payment credentials from the SIM. Further details of the research were provided at BlackHat on 31 July 2013.


title: SIM card

text: In response, the International Telecommunication Union said that the development was "hugely significant" and that it would be contacting its members.


title: SIM card

text: In February 2015, it was reported by The Intercept that the NSA and GCHQ had stolen the encryption keys (Ki's) used by Gemalto (the manufacturer of 2 billion SIM cards annually), enabling these intelligence agencies to monitor voice and data communications without the knowledge or approval of cellular network providers or judicial oversight. Having finished its investigation, Gemalto claimed that it has “reasonable grounds” to believe that the NSA and GCHQ carried out an operation to hack its network in 2010 and 2011, but says the number of possibly stolen keys would not have been massive.


title: SIM card

text: In September 2019, Cathal Mc Daid, a security researcher from Adaptive Mobile Security, described how vulnerabilities in some SIM cards that contained the S@T Browser library were being actively exploited. This vulnerability was named Simjacker. Attackers were using the vulnerability to track the location of thousands of mobile phone users in several countries. Further details of the research were provided at VirusBulletin on 3 October 2019.


title: SIM card

text: When GSM was already in use, the specifications were further developed and enhanced with functionality such as SMS and GPRS. These development steps are referred as releases by ETSI. Within these development cycles, the SIM specification was enhanced as well: new voltage classes, formats and files were introduced.


title: SIM card

text: In GSM-only times, the SIM consisted of the hardware and the software. With the advent of UMTS, this naming was split: the SIM was now an application and hence only software. The hardware part was called UICC. This split was necessary because UMTS introduced a new application, the universal subscriber identity module (USIM). The USIM brought, among other things, security improvements like mutual authentication and longer encryption keys and an improved address book.


title: SIM card

text: "SIM cards" in developed countries today are usually UICCs containing at least a SIM application and a USIM application. This configuration is necessary because older GSM only handsets are solely compatible with the SIM application and some UMTS security enhancements rely on the USIM application.


title: SIM card

text: On cdmaOne networks, the equivalent of the SIM card is the R-UIM and the equivalent of the SIM application is the CSIM.


title: SIM card

text: A "virtual SIM" is a mobile phone number provided by a mobile network operator that does not require a SIM card to connect phone calls to a user's mobile phone.


title: SIM card

text: An embedded SIM (eSIM) is a form of programmable SIM that is embedded directly into a device. The surface mount format provides the same electrical interface as the full size, 2FF and 3FF SIM cards, but is soldered to a circuit board as part of the manufacturing process. In M2M applications where there is no requirement to change the SIM card, this avoids the requirement for a connector, improving reliability and security. An eSIM can be provisioned remotely; end-users can add or remove operators without the need to physically swap a SIM from the device.


title: SIM card

text: An integrated SIM (iSIM) is a form of SIM directly integrated into the modem chip or main processor of the device itself. As a consequence they are smaller, cheaper and more reliable than eSIMs, they can improve security and ease the logistics and production of small devices i.e. for IoT applications. In 2021, the German Telekom introduced the nuSIM, an "Integrated SIM for IoT".


title: SIM card

text: The satellite phone networks Iridium, Thuraya and Inmarsat's BGAN also use SIM cards. Sometimes, these SIM cards work in regular GSM phones and also allow GSM customers to roam in satellite networks by using their own SIM cards in a satellite phone.


title: SIM card

text: Japan's 2G PDC system (which was shut down in 2012; SoftBank Mobile has already shut down PDC from 31 March 2010) also specifies a SIM, but this has never been implemented commercially. The specification of the interface between the Mobile Equipment and the SIM is given in the RCR STD-27 annexe 4. The Subscriber Identity Module Expert Group was a committee of specialists assembled by the European Telecommunications Standards Institute (ETSI) to draw up the specifications (GSM 11.11) for interfacing between smart cards and mobile telephones. In 1994, the name SIMEG was changed to SMG9.


title: SIM card

text: Japan's current and next-generation cellular systems are based on W-CDMA (UMTS) and CDMA2000 and all use SIM cards. However, Japanese CDMA2000-based phones are locked to the R-UIM they are associated with and thus, the cards are not interchangeable with other Japanese CDMA2000 handsets (though they may be inserted into GSM/WCDMA handsets for roaming purposes outside Japan).


title: SIM card

text: CDMA-based devices originally did not use a removable card, and the service for these phones is bound to a unique identifier contained in the handset itself. This is most prevalent in operators in the Americas. The first publication of the TIA-820 standard (also known as 3GPP2 C.S0023) in 2000 defined the Removable User Identity Module (R-UIM). Card-based CDMA devices are most prevalent in Asia.


title: SIM card

text: The equivalent of a SIM in UMTS is called the universal integrated circuit card (UICC), which runs a USIM application. The UICC is still colloquially called a "SIM card".


title: SIM card

text: The SIM card introduced a new and significant business opportunity for who lease capacity from one of the network operators rather than owning or operating a cellular telecoms network and only provide a SIM card to their customers. MVNOs first appeared in Denmark, Hong Kong, Finland and the UK. Today they exist in over 50 countries, including most of Europe, the United States, Canada, Mexico, Australia and parts of Asia, and account for approximately 10% of all mobile phone subscribers around the world.


title: SIM card

text: On some networks, the mobile phone is locked to its carrier SIM card, meaning that the phone only works with SIM cards from the specific carrier. This is more common in markets where mobile phones are heavily subsidised by the carriers, and the business model depends on the customer staying with the service provider for a minimum term (typically 12, 18 or 24 months). SIM cards that are issued by providers with an associated contract are called "SIM-only" deals. Common examples are the GSM networks in the United States, Canada, Australia, the UK and Poland. Many businesses offer the ability to remove the SIM lock from a phone, effectively making it possible to then use the phone on any network by inserting a different SIM card. Mostly, GSM and 3G mobile handsets can easily be unlocked and used on any suitable network with any SIM card.


title: SIM card

text: In countries where the phones are not subsidised, e.g., India, Israel and Belgium, all phones are unlocked. Where the phone is not locked to its SIM card, the users can easily switch networks by simply replacing the SIM card of one network with that of another while using only one phone. This is typical, for example, among users who may want to optimise their carrier's traffic by different tariffs to different friends on different networks, or when travelling internationally.


title: SIM card

text: In 2016, carriers started using the concept of automatic SIM reactivation whereby they let users reuse expired SIM cards instead of purchasing new ones when they wish to re-subscribe to that operator. This is particularly useful in countries where prepaid calls dominate and where competition drives high churn rates, as users had to return to a carrier shop to purchase a new SIM each time they wanted to churn back to an operator.


title: SIM card

text: Commonly sold as a product by mobile telecommunications companies, "SIM-only" refers to a type of legally binding contract between a mobile network provider and a customer. The contract itself takes the form of a credit agreement and is subject to a credit check.


title: SIM card

text: Within a SIM-only contract, the mobile network provider supplies their customer with just one piece of hardware, a SIM card, which includes an agreed amount of network usage in exchange for a monthly payment. Network usage within a SIM-only contract can be measured in minutes, text, data or any combination of these. The duration of a SIM-only contract varies depending on the deal selected by the customer, but in the UK they are available over 1, 3, 6, and 12-month periods.


title: SIM card

text: SIM-only contracts differ from mobile phone contracts in that they do not include any hardware other than a SIM card. In terms of network usage, SIM-only is typically more cost-effective than other contracts because the provider does not charge more to offset the cost of a mobile device over the contract period. The short contract length is one of the key features of SIM-only made possible by the absence of a mobile device.


title: SIM card

text: SIM-only is increasing in popularity very quickly. In 2010 pay monthly based mobile phone subscriptions grew from 41 per cent to 49 per cent of all UK mobile phone subscriptions. According to German research company GfK, 250,000 SIM-only mobile contracts were taken up in the UK during July 2012 alone, the highest figure since GfK began keeping records.


title: SIM card

text: Increasing smartphone penetration combined with financial concerns is leading customers to save money by moving onto a SIM-only when their initial contract term is over.


title: SIM card

text: Dual SIM devices have two SIM card slots for the use of two SIM cards, from one or multiple carriers. Multiple SIM devices are commonplace in developing markets such as in Africa, East Asia, South Asia and Southeast Asia, where variable billing rates, network coverage and speed make it desirable for consumers to use multiple SIMs from competing networks. Dual-SIM phones are also useful to separate one's personal phone number from a business phone number, without having to carry multiple devices. Some popular devices, such as the BlackBerry KeyOne, have dual-SIM variants; however, dual-SIM devices were not common in the US or Europe due to lack of demand. This has changed with mainline products from Apple and Google featuring either two SIM slots or a combination of a physical SIM slot and an eSIM.


title: SIM card

text: In September 2018, Apple introduced iPhone XS, iPhone XS Max, and iPhone XR featuring Dual SIM (nano-SIM and eSIM) and Apple Watch Series 4 featuring Dual eSIM.


title: SIM card

text: A thin SIM (or overlay SIM or SIM overlay) is a very thin device shaped like a SIM card, approximately 120 microns thick. It has contacts on its front and back. It is used by placing it on top of a regular SIM card. It provides its own functionality while passing through the functionality of the SIM card underneath. It can be used to bypass the mobile operating network and run custom applications, particularly on non-programmable cell phones.


title: SIM card

text: Its top surface is a connector that connects to the phone in place of the normal SIM. Its bottom surface is a connector that connects to the SIM in place of the phone. With electronics, it can modify signals in either direction, thus presenting a modified SIM to the phone, and/or presenting a modified phone to the SIM. It is a similar concept to the Game Genie, which connects between a game console and a game cartridge, creating a modified game. Similar devices have also been developed for iPhones to circumvent SIM card restrictions on carrier-locked models, thus allowing otherwise SIM-locked iPhones to accept SIM cards other than the ones they were authorised to accept.


title: SIM card

text: In 2014, Equitel, an MVNO operated by Kenya's Equity Bank, announced its intention to begin issuing thin SIMs to customers, raising security concerns by competition, particularly concerning the safety of mobile money accounts. However, after months of security testing and legal hearings before the country's Parliamentary Committee on Energy, Information and Communications, the Communications Authority of Kenya (CAK) gave the bank the green light to roll out its thin SIM cards.


title: Stairway to Heaven

text: "Stairway to Heaven" is a song by English rock band Led Zeppelin, released in late 1971. It was composed by the band's guitarist Jimmy Page and lead singer Robert Plant for their untitled fourth studio album (often titled "Led Zeppelin IV"). The song is widely regarded as one of the greatest rock songs of all time.


title: Stairway to Heaven

text: The song has three sections, each one progressively increasing in tempo and volume. The song begins in a slow tempo with acoustic instruments (guitar and recorders) before introducing electric instruments. The final section is an uptempo hard rock arrangement highlighted by Page's guitar solo (considered by many to be one of the greatest ever) accompanying Plant's vocals that end with the plaintive a cappella line: "And she's buying a stairway to heaven."


title: Stairway to Heaven

text: "Stairway to Heaven" was voted number three in 2000 by VH1 on its list of the 100 Greatest Rock Songs, in 2004 "Rolling Stone" magazine ranked "Stairway to Heaven" number 31 on its list of "500 Greatest Songs of All Time". It was the most requested song on FM radio stations in the United States in the 1970s, despite never having been commercially released as a single in the US. In November 2007, through download sales promoting Led Zeppelin's "Mothership" release, "Stairway to Heaven" reached number 37 on the UK Singles Chart.


title: Stairway to Heaven

text: Led Zeppelin began recording "Stairway to Heaven" in December 1970 at Island Records' new recording studios on Basing Street in London. The song was completed by the addition of lyrics by Plant during the sessions for "Led Zeppelin IV" at Headley Grange, Hampshire, in 1971. Page then returned to Island Studios to record his guitar solo.


title: Stairway to Heaven

text: The song originated in 1970 when Jimmy Page and Robert Plant were spending time at Bron-Yr-Aur, a remote cottage in Wales, following Led Zeppelin's fifth American concert tour. According to Page, he wrote the music "over a long period, the first part coming at Bron-Yr-Aur one night". Page always kept a cassette recorder around, and the idea for "Stairway to Heaven" came together from bits of taped music. The first attempts at lyrics, written by Robert Plant next to an evening log fire at Headley Grange, were partly spontaneously improvised and Page claimed, "a huge percentage of the lyrics were written there and then". Jimmy Page was strumming the chords, and Robert Plant had a pencil and paper.


title: Stairway to Heaven

text: The complete studio recording was released on "Led Zeppelin IV" in November 1971. The band's record label, Atlantic Records, wanted to issue it as a single, but the band's manager Peter Grant refused requests to do so in both 1972 and 1973. This led many people to buy the fourth album as if it were the single.


title: Stairway to Heaven

text: "Stairway to Heaven" is described as progressive rock, folk rock, and hard rock. The song consists of three distinct sections, beginning with a quiet introduction on a finger-picked, six-string acoustic guitar and four recorders (ending at 2:15) and gradually moving into a slow electric middle section (2:16–5:33), then a long guitar solo (5:34–6:44), before the faster hard rock final section (6:45–7:45), ending with a short vocals-only epilogue. Plant sings the opening, middle, and epilogue sections in his mid-vocal range; he sings the hard rock section in his higher range, which borders on falsetto.


title: Stairway to Heaven

text: Written in the key of A minor, the song opens with an arpeggiated, finger-picked guitar chord progression with a chromatic descending bassline A-G♯-G-F♯-F. John Paul Jones contributed overdubbed wooden bass recorders in the opening section (he used a Mellotron and, later, a Yamaha CP-70B Grand Piano and Yamaha GX1 to synthesise this arrangement in live performances) and a Hohner Electra-Piano electric piano in the middle section.


title: Stairway to Heaven

text: The sections build with more guitar layers, each complementary to the intro, with the drums entering at 4:18. The extended Jimmy Page guitar solo in the song's final section was played for the recording on a 1959 Fender Telecaster given to him by Jeff Beck (an instrument he used extensively with the Yardbirds) plugged into a Supro amplifier, although in an interview he gave to "Guitar World" magazine, Page said, "It could have been a Marshall, but I can't remember". Three different improvised solos were recorded, with Page agonising about which to keep. Page later revealed, "I did have the first phrase worked out, and then there was the link phrase. I did check them out beforehand before the tape ran." He has likened the song to an orgasm. The Am–G–F–G chord sequence in the third section of the song, centred on A minor, is typical of a chord progression in the Aeolian mode.


title: Stairway to Heaven

text: The inaugural public performance of the song took place at Belfast's Ulster Hall on 5 March 1971. Bassist John Paul Jones recalls that the crowd was unimpressed: "They were all bored to tears waiting to hear something they knew."


title: Stairway to Heaven

text: The world radio premiere of "Stairway to Heaven" was recorded at the Paris Cinema on 1 April 1971, in front of a live studio audience, and broadcast three days later on the BBC. The song was performed at almost every subsequent Led Zeppelin concert, only being omitted on rare occasions when shows were cut short for curfews or technical issues. The band's final performance of the song was in Berlin on 7 July 1980, which was also their last full-length concert until 10 December 2007 at London's O2 Arena; the version was the longest, lasting almost 15 minutes, including a seven-minute guitar solo.


title: Stairway to Heaven

text: When playing the song live, the band would often extend it to over 10 minutes, with Page playing an extended guitar solo and Plant adding a number of lyrical ad-libs, such as "Does anybody remember laughter?", "And I think you can see that", "wait a minute!" and "I hope so". For performing this song live, Page used a Gibson EDS-1275 double neck guitar so he would not have to pause when switching from a six to a 12-string guitar, while John Paul Jones utilized a mellotron to replicate the recorders used on the studio recording.


title: Stairway to Heaven

text: By 1975, the song had a regular place as the finale of every Led Zeppelin concert. However, after their concert tour of the United States in 1977, Plant began to tire of "Stairway to Heaven": "There's only so many times you can sing it and mean it... It just became sanctimonious."


title: Stairway to Heaven

text: The song was played again by the surviving members of Led Zeppelin at the Live Aid concert in 1985; at the Atlantic Records 40th Anniversary concert in 1988, with Jason Bonham on drums; and by Jimmy Page as an instrumental version on his solo tours.