火药的英语介绍

火药：power指南针：compass造纸术：paper-making活字印刷：movable type

四大发明”,英文名为“TheFourGreatInventions

分别是“造纸术”英文名为“Papermaking”、“火药”英文名为“Gunpowder”、“印刷术”英文名为“Priniting Technique”、“指南针”英文名为“Compass”

1、造纸术：发明时期于汉朝西汉时期，改进时期于汉朝东汉时期。它是人类文明史上的一项杰出的发明创造。中国古代造纸术的起源同丝絮有着渊源关系。东汉元兴元年蔡伦改进了造纸术。 他用树皮、麻头及敝布、渔网等原料，经过挫、捣、炒、烘等工艺制造的纸，是现代纸的渊源。

2、指南针：古代叫司南，主要组成部分是一根装在轴上的磁针，磁针在天然地磁场的作用下可以自由转动并保持在磁子午线的切线方向上，磁针的南极指向地理南极(磁场北极)，利用这一性能可以辨别方向。常用于航海、大地测量、旅行及军事等方面。

物理上指示方向的指南针的发明有三类部件，分别是司南、罗盘和磁针，都是古代中国的发明。在中国古代，指南针应用于祭祀、礼仪、军事和占卜与看风水时确定方位。

3、火药：顾名思义，可由火花、火焰等引起剧烈燃烧的药剂。据记载在春秋时代的中国就已经用于民间民生应用，范子计然说“硝石出陇道”。火药的发明是人们长期炼丹，制药实践结果，至今已有一千多年历史。

4、印刷术：雕版印刷术发明于唐朝，并在唐朝中后期普遍使用。 宋仁宗时毕升发明了活字印刷术。虽然出现活字印刷术，但并未普遍使用，而仍然是普遍使用雕版印刷术。

印刷术是人类近代文明的先导，为知识的广泛传播、交流创造了条件。印刷术先后传到朝鲜、日本、中亚，西亚和欧洲地区。

四大发明历史意义：

四大发明是中国古代先民为世界留下的一串光耀的足迹，是人类文明进步作出巨大贡献的象征

1、造纸术的发明：为人类提供了经济﹑便利的书写材料，掀起一场人类文字载体革命

2、 雕版印刷术的发明：大大促进了文化的传播

3、指南针的发明：为欧洲航海家的航海活动，提供了条件

4、火药武器的发明：火药武器的使用，改变了作战方式，帮助欧洲资产阶级摧毁了封建堡垒，加速了欧洲的历史进程。

Gunpowder, also called black powder, is an explosive mixture of sulfur, charcoal and potassium nitrate, KNO3 (also known as saltpetre/saltpeter) that burns rapidly, producing volumes of hot solids and gases which can be used as a propellant in firearms and as a pyrotechnic composition in fireworks. The term gunpowder is also often used more broadly to describe any propellant powder used in firearms. Modern firearms do not use the traditional gunpowder (black powder) described in this article, but instead use smokeless powder. In this article, the terms gunpowder and black powder are used interchangeably.Gunpowder is classified as a low explosive because of its slow decomposition rate and consequently low brisance. Low explosives produce a subsonic deflagration wave rather than the supersonic detonation wave produced by brisants, or high explosives. The gases produced by burning gunpowder generate enough pressure to propel a bullet, but not enough to destroy the barrel of a firearm. This makes gunpowder less suitable for shattering rock or fortifications, where high explosives such as TNT are preferred.The term "black powder" was coined in the late 19th century to distinguish prior gunpowder formulations from the new smokeless powders and semi-smokeless powders. (Semi-smokeless powders featured bulk volume properties that approximated black powder in terms of chamber pressure when used in firearms, but had significantly reduced amounts of smoke and combustion products; they ranged in color from brownish tan to yellow to white. Most of the bulk semi-smokeless powders ceased to be manufactured in the 1920s.)[1][2][3]Black powder is a granular mixture ofa nitrate—typically potassium nitrate (KNO3)—which supplies oxygen for the reaction; charcoal, which provides fuel for the reaction in the form of carbon (C); sulfur (S), which, while also a fuel, lowers the temperature of ignition and increases the speed of combustion. Potassium nitrate is the most important ingredient in terms of both bulk and function because the combustion process releases oxygen from the potassium nitrate, promoting the rapid burning of the other ingredients.[4] To reduce the likelihood of accidental ignition by static electricity, the granules of modern black powder are typically coated with graphite, which prevents the build-up of electrostatic charge.The current standard composition for black powder manufactured by pyrotechnicians was adopted as long ago as 1780. It is 75% potassium nitrate, 15% softwood charcoal, and 10% sulfur.[5] These ratios have varied over the centuries and by country, and can be altered somewhat depending on the purpose of the powder. For instance, coarser grades of black powder, unsuitable for use in firearms but adequate for blasting rock in quarrying operations, is called blasting powder rather than gun powder; it is often made with the cheaper sodium nitrate substituted for potassium nitrate in proportions of 60% nitrate, 20% charcoal and 20% sulfur.[citation needed]The burn rate of black powder can be changed by corning. Corning first compresses the fine black powder meal into blocks with a fixed density (1.7 g/cm³). The blocks are then broken up into granules. These granules are then sorted by size to give the various grades of black powder. In the United States, standard grades of black powder run from the coarse Fg grade used in large bore rifles and small cannons, through FFg (medium and smallbore arms such as muskets and fusils), FFFg (smallbore rifles and pistols), and FFFFg (extreme small bore, short pistols and most commonly for priming flintlocks). In the United Kingdom, the gunpowder grains are categorised by mesh size: the BSS sieve mesh size, being the smallest mesh size on which no grains were retained. Recognised grain sizes are Gunpowder 'G 7', 'G 20', 'G 40', and 'G 90'.