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Gunpowder, also known as black powder, is a chemical explosive—the earliest known. It is a mixture of sulfur, charcoal, and potassium nitrate (saltpeter). The sulfur and charcoal act as fuels, and the saltpeter is an oxidizer.〔David Cressy, ''Saltpeter: The Mother of Gunpowder'' (Oxford University Press, 2013)〕 Because of its burning properties and the amount of heat and gas volume that it generates, gunpowder has been widely used as a propellant in firearms and as a pyrotechnic composition in fireworks. Formulations used in blasting rock (such as in quarrying) are called blasting powder. Gunpowder is mainly used in older guns now because the propellants used today are too powerful and could break the already fragile barrels. Gunpowder is assigned the UN number UN0027 and has a hazard class of 1.1D. It has a flash point of approximately 427–464 °C (801–867 °F). The specific flash point may vary based on the specific composition of the gunpowder. Gunpowder's specific gravity is 1.70–1.82 (mercury method) or 1.92–2.08 (pycnometer), and it has a pH of 6.0–8.0. It is also considered to be an insoluble material. Gunpowder was, according to prevailing academic consensus, invented in the 9th century in China,〔(【引用サイトリンク】title=Who Built It First? )〕〔(【引用サイトリンク】title=Gunpowder Facts, History and Description )〕 and the earliest record of a written formula for gunpowder appears in the 11th century Song dynasty text, ''Wujing Zongyao''.〔 : "the earliest surviving formulas for gunpowder can be found in the Wujing zongyao, a military work from around 1040"〕 This discovery led to the invention of fireworks and the earliest gunpowder weapons in China. In the centuries following the Chinese discovery, gunpowder weapons began appearing in the Muslim world, Europe, and India. The technology spread from China through the Middle East or Central Asia, and then into Europe.〔 The earliest Western accounts of gunpowder appear in texts written by English philosopher Roger Bacon in the 13th century.〔 Gunpowder is classified as a low explosive because of its relatively slow decomposition rate and consequently low brisance. Low explosives deflagrate (i.e., burn) at ''subsonic'' speeds, whereas high explosives detonate, producing a ''supersonic'' wave. Gunpowder's burning rate increases with pressure, so it will burst containers but just burns in the open. Ignition of the powder packed behind a bullet must generate enough pressure to force it from the muzzle at high speed, but not enough to rupture the gun barrel. Gunpowder thus makes a good propellant, but is less suitable for shattering rock or fortifications. Gunpowder was widely used to fill artillery shells and in mining and civil engineering to blast rock roughly until the second half of the 19th century, when the first high explosives (nitro-explosives) were devised and formulated. Gunpowder is no longer used in modern explosive military warheads, nor is it used as main explosive in mining operations due to its cost relative to that of newer alternatives such as ammonium nitrate/fuel oil (ANFO). Black powder is still used as a delay element in various munitions where its slow-burning properties are valuable. ==History== (詳細はChina when Taoists attempted to create a potion of immortality. Chinese military forces used gunpowder-based weapons (i.e. rockets, guns, cannons) and explosives (i.e. grenades and different types of bombs) against the Mongols when the Mongols attempted to invade and breach city fortifications on China's northern borders. After the Mongols conquered China and founded the Yuan Dynasty, they used the Chinese gunpowder-based weapons technology in their attempted invasion of Japan; they also used gunpowder to fuel rockets. The mainstream scholarly consensus is that gunpowder was invented in China, spread through the Middle East, and then into Europe,〔 although there is a dispute over how much the Chinese advancements in gunpowder warfare influenced later advancements in the Middle East and Europe.〔Jack Kelly ''Gunpowder: Alchemy, Bombards, and Pyrotechnics: The History of the Explosive that Changed the World'', Perseus Books Group: 2005, ISBN 0-465-03722-4, ISBN 978-0-465-03722-3: 272 pages〕〔St. C. Easton: "Roger Bacon and his Search for a Universal Science", Oxford (1962)〕 The spread of gunpowder across Asia from China is widely attributed to the Mongols. One of the first examples of Europeans encountering gunpowder and firearms is at the Battle of Mohi in 1241. At this battle the Mongols not only used gunpowder in early Chinese firearms but in the earliest grenades as well. A major problem confronting the study of the early history of gunpowder is ready access to sources close to the events described. Often enough, the first records potentially describing use of gunpowder in warfare were written several centuries after the fact, and may well have been colored by the contemporary experiences of the chronicler. It is also difficult to accurately translate original alchemy texts, especially medieval Chinese texts that try to explain phenomena through metaphor, into modern scientific language with rigidly defined terminology. The translation difficulty has led to errors or loose interpretations bordering on artistic licence.〔Ingham-Brown, George (1989) ''The Big Bang: A History of Explosives'', Sutton Publishers, ISBN 0-7509-1878-0, ISBN 978-0-7509-1878-7, page vi〕〔Kelly, Jack (2005) ''Gunpowder: Alchemy, Bombards, and Pyrotechnics: The History of the Explosive that Changed the World'', Perseus Books Group, ISBN 0-465-03722-4, ISBN 978-0-465-03722-3, page 22〕 Early writings potentially mentioning gunpowder are sometimes marked by a linguistic process where old words acquired new meanings.〔Bert S. Hall, "Introduction, 1999" pp. xvi–xvii to the reprinting of 〕 For instance, the Arabic word ''naft'' transitioned from denoting naphtha to denoting gunpowder, and the Chinese word ''pao'' evolved from meaning catapult to referring to cannon. According to science and technology historian Bert S. Hall: "It goes without saying, however, that historians bent on special pleading, or simply with axes of their own to grind, can find rich material in these terminological thickets."〔Bert S. Hall, "Introduction, 1999" p. xvii to the reprinting of 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gunpowder」の詳細全文を読む スポンサード リンク
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