An explosive is a stable substance or device that upon detonation produces a volume of rapidly expanding gas that exerts sudden pressure on its surroundings.

An explosive is a stable substance or device that upon detonation produces a volume of rapidly expanding gas that exerts sudden pressure on its surroundings. In general, explosives are divided into two general types: propellants and detonators. Propellants, such as gunpowder and jet fuel, are used to accelerate Projectiles;propellants forprojectiles, particularly bullets and rockets. Detonators, such as dynamite (trinitrotoluene, or TNT), are often used to ignite PropellantsDetonatorspropellants. Detonators that can be touched off only by a high-energy source are termed high explosives.GunpowderExplosivesGunpowderExplosives

Explosives are further classified as blasting Blasting explosivesexplosives and military Explosivesexplosives. Blasting explosives are typically used in mining, construction, and tunnel building. Military explosives are used in bombs, explosive shells, torpedoes, and missile warheads. Military explosives must be physically and chemically stable over extreme ranges of temperature and humidity for long periods of time. They must also be insensitive to impacts, such as those experienced by an artillery shell when it is fired from a gun or penetrates steel armor. Military explosives are used for a wide range of purposes: They are fired in projectiles and dropped in aerial time bombs without premature explosion. Raw materials necessary to manufacture such explosives must be readily available for high rates of production during wartime.

Another classification of explosives separates them into chemical, mechanical, and nuclear types. Chemical Chemical weapons;explosivesexplosives, such as gunpowder and dynamite, are the most commonly used and explode through chemical reactions. Mechanical Mechanical explosivesexplosives involve physical reactions, such as a container’s being overloaded with compressed air. Nuclear Nuclear weapons and warfare;explosivesexplosives produce a sustained nuclear reaction and are the most powerful explosives.

A hand grenade.

(©IMV/Dreamstime.com)

The first known explosive was black powder, also known as gunpowder. It was developed in China;gunpowderChina during the tenth century or possibly earlier. The initial purpose was for use in fireworks and signals. The first European mention of gunpowder was by thirteenth century scientist and educator Roger Bacon, RogerBacon, RogerBacon (1220-1292), who recorded a recipe in 1267. His term, “fire for burning up the enemy,” suggests that Bacon regarded Gunpowder;recipes forgunpowder as an incendiary, not a propellant. The composition he suggested endured for more than three hundred years and consisted of 75 percent potassium nitrate (saltpeter), 15 percent charcoal, and 10 percent sulfur. The charcoal and sulfur constitute the fuel of the powdered mixture, whereas the saltpeter acts as the oxidizer.

Black Black powderpowder revolutionized warfare and played a significant role in the development of European patterns of living up until modern times. The Chinese first used black powder as a gun propellant as early as 1130, placing it in bamboo tubes that were reinforced with iron to propel stone projectiles and arrows. When used in war, gunpowder was often more successful in creating fear in the enemy ranks than in inflicting actual damage. Chinese records indicate that the Chinese used black powder in Bombs;Chinabombs for military purposes. Torches, glowing tinder, or heated iron rods were used to ignite the powder, and usually, a trail of the powder led to the main charge in order to give the firer time to reach safety.

Firearms Firearms;gunpowderthat use gunpowder are frequently mentioned in fourteenth century manuscripts from many different countries. By the end of the fourteenth century, many countries were using gunpowder as a military aid to breach the walls of castles and cities. Although black powder remained the standard gun propellant until the late nineteenth century, it is now used only in igniters, safety fuses, and fireworks.

In 1425 the mixing process for the ingredients of black powder was greatly improved when the Corned powdercorning, or granulating, process was developed in England. Heavy wheels ground and pressed the fuel and oxidizer into a solid mass that was subsequently broken down into smaller grains. The first gunpowder mill was erected near Nuremberg, Germany, in about 1435. Corned gunpowder was used for small guns and hand grenades during the fifteenth century.

By 1540 the French had become the first people to control explosive pressure in wheeled cannons by using relatively large, slow-burning powder grains of uniform size. In the seventeenth century, the English and Dutch militaries developed the Howitzershowitzer, a short cannon firing explosive shells in a high arc to hit a distant target. Large muskets were used in America with some success during the French and Indian War (1754-1763). Shorter, lighter Musketsmuskets were the most widely used weapon in the American Revolution American Revolution (1775-1783)(1775-1783). If the French had developed more fieldworthy muskets, they might have had more success in the Napoleonic Wars (1793-1815).

In the 1790’s Henry ShrapnelShrapnel (1761-1842), an English Artillery;and explosives[explosives]artillery officer, developed the “shrapnel shell,” consisting of a spherical shell packed with a small charge of black powder and several musket balls. These single-shot multiple explosives were effective against concentrations of enemy troops. By using batteries of many guns, massed artillery fire was employed to destroy attacking enemy formations or to disrupt defending forces before they could launch an attack. During the early 1800’s, mobile artilleries, including horse-drawn units, were used to shift explosives from one strategic location to another on the battlefield.

In 1805 English artillerist Sir William Congreve, WilliamCongreve, WilliamCongreve (1772-1828) used gunpowder to develop Rockets;earlyrockets for warfare and launching tubes to greatly improve the rockets’ accuracy. Congreve’s inventions expanded the use of rockets for military purposes, greatly changing the way war was waged in Europe. Hand-to-hand Hand-to-hand combat[hand to hand combat];decline ofcombat with specific implied rules of chivalry became outdated, as more powerful gunpowder weapons that produced a higher number of casualties and more serious wounds were adopted. Congreve’s rockets were used to bombard Boulogne, Copenhagen, and Danzig in the Napoleonic Wars and in the British attack on Fort McHenry (1814), near Baltimore, Maryland, during the War of 1812 (1812-1815).

The development of different types of guns to propel explosive charges became critical in warfare. In the Crimean War Crimean War (1853-1856)(1853-1856), Russian troops armed with smoothbore Smoothbore weaponsmuskets were no match for the British, with their more advanced musket Riflesrifles. The deadly effect of rifled muskets was clearly demonstrated during the American Civil War American Civil War (1861-1865);firearms(1861-1865). Because individual soldiers could hit their enemies with accurate fire out to 250 yards, frontal attacks, in which soldiers advanced in ordered ranks across open fields, had to be abandoned. By 1862 both Union and Confederate troops had built field entrenchments and barricades to provide protection from artillery explosives. During the Battle ofKöniggrätz, Battle of (1866)[Koniggratz]Königgrätz in the Seven Weeks’ War Seven Weeks’ War (1866)(1866), Prussian soldiers were able to overwhelm the Austrians by firing six shots from their high-powered rifles for every shot discharged by the Austrian muzzle-loading rifles.

During the Battle of Königgrätz, Prussian soldiers were able to overwhelm the Austrians by firing six shots from their high-powered rifles for every shot discharged by the Austrian muzzle-loading rifles.

(F. R. Niglutsch)

Until the discovery of fulminating gold in the early 1600’s, gunpowder was the only known explosive. Gunpowder remained in wide use until the mid-1800’s, when the first modern explosives, Nitroglycerinnitroglycerin and dynamite, were invented. Nitroglycerin was discovered by an Italian chemist, Ascanio Sobrero, AscanioSobrero, AscanioSobrero (1812-1888), in 1847. Its value for blasting was later demonstrated by Swedish inventor Alfred B. Nobel, Alfred B.Nobel, Alfred B.Nobel (1833-1896), who also invented Dynamitedynamite in 1866. Stable ammonia dynamites began to appear in the late 1880’s, followed by low-freezing dynamites after 1925.

Since black powder is relatively low in energy, leaves a large proportion of corrosive solids after explosion, and absorbs moisture readily, it was succeeded in the late 1800’s by smokeless Smokeless powdergunpowder and picric acid. The first smokeless powder, known as Corditecordite, was invented by English chemists Sir James Dewar, JamesDewar, JamesDewar (1842-1923) and Sir Frederick Augustus Abel, Frederick AugustusAbel, Frederick AugustusAbel (1827-1902) in 1889. It was made in two forms: a gelatinized nitrocellulose and a mixture of nitrocellulose and nitroglycerin, with a small quantity of petroleum jelly to act as a stabilizer. Smokeless powder soon became the primary ammunition used in Pistols;gunpowder inpistols.

As early as 1873 picric Picric acidacid was detonated to produce explosions, and it was found in 1885 to be a suitable replacement for black powder. From 1888 into World War I, it was used as the basic explosive for military purposes. Because it required prolonged heating at high temperatures in order to melt, and because it also caused shells to corrode in the presence of water, an active search for better explosives continued.

During the twentieth century, TNT was the most commonly used conventional military explosive. Although it had been used extensively in the dye industry during the late 1800’s, it was not adopted for use as a military explosive until 1902, when the German army used it to replace picric acid. TNT was first used in warfare during the Russo-Japanese War (1904-1905). The U.S. Army began using it in 1912. After an economical process was developed for nitrating toluene, TNT became the chief artillery ammunition in World War I (1914-1918). The most valuable property of TNT is that it can be safely melted and cast alone or with other explosives as a slurry.

During World War World War I (1914-1918)[World War 01];rifles inI, all of the major powers adopted smokeless powder, bolt-action, magazine-fed repeating rifles. These rapid-fire weapons rendered the battlefield a “no-man’s-land.” Massed artillery explosive fire denied both sides the ability to maneuver forces, a condition that led to trench Trench warfare;World War I[World War 01]warfare, such as at the Battle of the Marne, Battle of the (1914)Marne (1914), where the Allies stopped the Germans from advancing farther into France. As a result, gas shell Projectiles;gas shellGas;World War I[World War 01]projectiles loaded with chlorine and mustard gas were employed against the enemy. The Germans also made wide use of liquid oxygen explosives during World War I.

With the advent of tanks, World War II (1939-1945) saw a return to maneuver tactics, with artillery explosives continuing to provide the most destructive force on the battlefield. NitroguanidineNitroguanidine, referred to as Gudol Gudol PulverPulver, was a primary explosive used during World War World War II (1939-1945)[World War 02];explosives inII. It produced very little smoke, had no evidence of a muzzle flash on firing, and also increased the lifetime of the gun barrel. Pentaerythitol tetranitrate Pentaerythitol tetranitrate (PETN)(PETN) and cyclotrimethylene trinitramine RDX (explosive)(RDX) were developed for use as detonators and for filling hand and antitank grenades. A mixture of TNT, RDX, and wax was used to detonate bombs. A mixture of PETN and TNT was used for detonating demolition charges. TorpedoesTorpedo warheads were often made of cast mixtures of RDX, TNT, and aluminum.

Some of the most effective weapons used during World War II were Missiles;World War II[World War 02]missiles, consisting of a rocket that delivered an explosive charge called a Warheadswarhead. The first successful long-range ballistic Ballistic missilesRockets;World War II[World War 02]missile was the German V-2 that was principally developed by Wernher von Braun, Wernher vonBraun, Wernher vonBraun (1912-1977), a pioneer of German rocketry. These missiles were launched into England from German-occupied countries in Europe. Most ballistic missiles, aircraft munitions, and artillery use solid rocket propellants.

The atomic Atomic bombbomb was the first nuclear weapon to be developed, tested, and used. Developed under the direction of American physicist J. Robert Oppenheimer, J. RobertOppenheimer, J. RobertOppenheimer (1904-1967), it was implemented near the end of World War II. On August 6, 1945, an atomic bomb was dropped by an American B-29 bomber, the Enola Gay (bomber) Enola Gay, over Hiroshima, Japan Hiroshima, Japan, instantly killing more than 70,000 people. On August 9, the United States dropped a second atomic bomb, killing some 40,000 people in Nagasaki, Nagasaki, Japan Japan. Due to such devastation, this explosive device has never again been used in a war.

In more recent conflicts, such as the Korean War Korean War (1950-1953)(1950-1953) and the Vietnam War (1961-1975)Vietnam War (1961-1975), artillery explosives provided most of the fire support for ground forces. Laser-guided projectiles were developed to destroy tanks. During this period the United States began using medium-sized Howitzershowitzers capable of firing chemical and nuclear explosives. Grenade Grenades;launcherslaunchers saw a great deal of action in Vietnam, and search-and-destroy air explosives razed numerous Vietnamese villages.

During the 1990’s advances in onboard Computers;weapons usecomputer systems and self-locating capabilities enabled modern cannons and missile launchers to move independently around the battlefield, stopping to fire explosives and then quickly moving to a new firing position. Some modern artillery cannons and launchers can deliver “smart” explosives. These projectiles and warheads use sophisticated seekers and sensors to locate and home in on stationary or moving targets.GunpowderExplosives

• Akhavan, Jacqueline. The Chemistry of Explosives. Cambridge, England: The Royal Society of Chemistry, 1998.
• Brown, G. I. The Big Bang: A History of Explosives. Stroud, Gloucestershire, England: Sutton, 1998.
• Buchanan, Brenda J. Gunpowder: The History of an International Technology. Bath, England: Bath University Press, 1996.
• _______, ed. Gunpowder, Explosives, and the State: A Technological History. Burlington, Vt.: Ashgate, 2006.
• Cooper, Paul W., and Stanley R. Kurowski. Introduction to the Technology of Explosives. New York: Wiley-VCH, 1996.
• Guilmartin, John Francis, Jr. Gunpowder and Galleys: Changing Technology and Mediterranean Warfare at Sea in the Sixteenth Century. Rev. ed. Annapolis, Md.: Naval Institute Press, 2003.
• Kelly, Jack. Gunpowder–Alchemy, Bombards, and Pyrotechnics: The History of the Explosive That Changed the World. New York: Basic Books, 2004.
• Neiberg, Michael S. “The Emergence of Gunpowder Weapons, 1450 to 1776.” In Warfare in World History. London: Routledge, 2001.
• Partington, James R. A History of Greek Fire and Gunpowder. Baltimore: Johns Hopkins University Press, 1998.
• Wilson, Clay. Improvised Explosive Devices in Iraq: Effects and Countermeasures. Washington, D.C.: Congressional Research Service, Library of Congress, 2005.

• Deadly Explosives. Documentary. Paladin Press, 1997.
• High Explosives. Documentary. History Channel, 1998.
• Modern Marvels: Bombs. Documentary. History Channel, 2005.
• Tactical Use of Explosives. Documentary. Spy Tech Agency, 1996.

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