Abomb is anexplosive weapon that uses theexothermic reaction of anexplosive material to provide an extremely sudden and violent release ofenergy.Detonations inflict damage principally through ground- and atmosphere-transmittedmechanical stress, the impact and penetration of pressure-driven projectiles, pressure damage, and explosion-generated effects.[1] Bombs have been utilized since the 11th century starting inEast Asia.[2]
The termbomb is not usually applied to explosive devices used forcivilian purposes such asconstruction ormining, although the people using the devices may sometimes refer to them as a "bomb". The military use of the term "bomb", or more specificallyaerial bomb action, typically refers to airdropped, unpowered explosive weapons most commonly used byair forces andnaval aviation. Other military explosive weapons not classified as "bombs" includeshells,depth charges (used in water), orland mines. Inunconventional warfare, other names can refer to a range of offensive weaponry. For instance, in recentasymmetric conflicts, homemade bombs called "improvised explosive devices" (IEDs) have been employed byirregular forces to great effectiveness.
The word comes from theLatinbombus, which in turn comes from theGreekβόμβοςromanizedbombos,[3] anonomatopoetic term meaning 'booming', 'buzzing'.
A "wind-and-dust" bomb depicted in theMing Dynasty bookHuolongjing. The pot contains a tube of gunpowder, and was thrown at invaders.[4]
An illustration depicting bombs thrown at Manchu assault ladders during the siege of Ningyuan, from the bookThai Tsu Shih Lu Thu (Veritable Records of the Great Ancestor) written in 1635. The bombs are known as "thunder crash bombs."[5]
Gunpowder bombs had been mentioned since the 11th century. In 1000 AD, a soldier by the name of Tang Fu (唐福) demonstrated a design of gunpowder pots (a proto-bomb which spews fire) and gunpowder caltrops, for which he was richly rewarded.[6] In the same year, Xu Dong wrote that trebuchets used bombs that were like "flying fire", suggesting that they were incendiaries.[7] In the military textWujing Zongyao of 1044, bombs such as the "ten-thousand fire flying sand magic bomb", "burning heaven fierce fire unstoppable bomb", and "thunderclap bomb" (pilipao) were mentioned. However these were soft-shell bombs and did not use metal casings.[8][9]
Bombs made of cast iron shells packed with explosive gunpowder date to 13th century China.[10] Explosive bombs were used in East Asia in 1221, by aJurchen Jin army against aChinese Song city.[2] The term for this explosive bomb seems to have been coined the "thunder crash bomb" during aJin dynasty (1115–1234) naval battle in 1231 against theMongols.[10]
TheHistory of Jin (金史) (compiled by 1345) states that in 1232, as the Mongol generalSubutai (1176–1248) descended on the Jin stronghold ofKaifeng, the defenders had a "thunder crash bomb" which "consisted of gunpowder put into an iron container ... then when the fuse was lit (and the projectile shot off) there was a great explosion the noise whereof was like thunder, audible for more than thirty miles, and the vegetation was scorched and blasted by the heat over an area of more thanhalf amou. When hit, eveniron armour was quite pierced through."[10]
The Song Dynasty (960–1279) official Li Zengbo wrote in 1257 thatarsenals should have several hundred thousand iron bomb shells available and that when he was inJingzhou, about one to two thousand were produced each month for dispatch of ten to twenty thousand at a time toXiangyang and Yingzhou.[10] The Ming Dynasty textHuolongjing describes the use of poisonous gunpowder bombs, including the "wind-and-dust" bomb.[4]
During theMongol invasions of Japan, the Mongols used the explosive "thunder-crash bombs" against the Japanese. Archaeological evidence of the "thunder-crash bombs" has been discovered in an underwater shipwreck off the shore of Japan by the Kyushu Okinawa Society for Underwater Archaeology. X-rays by Japanese scientists of the excavated shells confirmed that they contained gunpowder.[11]
Shock waves produced by explosive events have two distinct components, the positive and negative wave. The positive wave shoves outward from the point of detonation, followed by the trailing vacuum space "sucking back" towards the point of origin as the shock bubble collapses. The greatest defense against shock injuries is distance from the source of shock.[13] As a point of reference, the overpressure at theOklahoma City bombing was estimated in the range of28MPa.[14]
Heat
A thermal wave is created by the sudden release of heat caused by an explosion. Military bomb tests have documented temperatures of up to 2,480 °C (4,500 °F). While capable of inflicting severe to catastrophic burns and causing secondary fires, thermal wave effects are considered very limited in range compared to shock and fragmentation. This rule has been challenged, however, by military development ofthermobaric weapons, which employ a combination of negative shock wave effects and extreme temperature to incinerate objects within the blast radius.
An illustration of a fragmentation bomb from the 14th century Ming Dynasty textHuolongjing. The black dots represent iron pellets.
Fragmentation is produced by the acceleration of shattered pieces of bomb casing and adjacent physical objects. The use of fragmentation in bombs dates to the 14th century, and appears in theMing Dynasty textHuolongjing. The fragmentation bombs were filled with iron pellets and pieces of broken porcelain. Once the bomb explodes, the resulting fragments are capable of piercing the skin and blinding enemy soldiers.[15]
While conventionally viewed as small metal shards moving at super-supersonic andhypersonic speeds, fragmentation can occur in epic proportions and travel for extensive distances. When the SSGrandcamp exploded in theTexas City Disaster on April 16, 1947, one fragment of that blast was a two-ton anchor which was hurled nearly two miles inland to embed itself in the parking lot of the Pan American refinery.
Effects on living things
To people who are close to a blast incident, such as bomb disposal technicians, soldiers wearing body armor, deminers, or individuals wearing little to no protection, there are four types of blast effects on the human body:overpressure (shock),fragmentation,impact, andheat. Overpressure refers to the sudden and drastic rise in ambient pressure that can damage the internal organs, possibly leading to permanent damage or death. Fragmentation can also include sand, debris and vegetation from the area surrounding the blast source. This is very common in anti-personnel mine blasts.[16] The projection of materials poses a potentially lethal threat caused by cuts in soft tissues, as well as infections, and injuries to the internal organs. When the overpressure wave impacts the body it can induce violent levels of blast-induced acceleration. Resulting injuries may range from minor to unsurvivable. Immediately following this initial acceleration, deceleration injuries can occur when a person impacts directly against a rigid surface or obstacle after being set in motion by the force of the blast. Finally, injury and fatality can result from the explosive fireball as well as incendiary agents projected onto the body.Personal protective equipment, such as abomb suit or demining ensemble, as well as helmets, visors and foot protection, can dramatically reduce the four effects, depending upon the charge, proximity and other variables.
Experts commonly distinguish between civilian and military bombs. The latter are almost always mass-produced weapons, developed and constructed to a standard design out of standard components and intended to be deployed in a standard explosive device.IEDs are divided into three basic categories by basic size and delivery. Type 76, IEDs are hand-carried parcel or suitcase bombs, type 80, are "suicide vests" worn by a bomber, and type 3 devices are vehicles laden with explosives to act as large-scale stationary or self-propelled bombs, also known asVBIED (vehicle-borne IEDs).[citation needed]
Improvised explosive materials are typically unstable and subject to spontaneous, unintentional detonation triggered by a wide range of environmental effects, ranging fromimpact andfriction toelectrostatic shock. Even subtlemotion, change intemperature, or the nearby use of cellphones or radios can trigger an unstable or remote-controlled device. Any interaction with explosive materials or devices by unqualified personnel should be considered a grave and immediate risk of death or dire injury. The safest response to finding an object believed to be an explosive device is to get as far away from it as possible.
Atomic bombs are based on the theory ofnuclear fission, that when a large atom splits, it releases a massive amount of energy.Thermonuclear weapons, (colloquially known as "hydrogen bombs") use the energy from an initialfission explosion to create an even more powerfulfusion explosion.
The term "dirty bomb" refers to a specialized device that relies on a comparatively low explosive yield to scatter harmful material over a wide area. Most commonly associated withradiological or chemical materials, dirty bombs seek to kill or injure and then to deny access to a contaminated area until a thorough clean-up can be accomplished. In the case of urban settings, this clean-up may take extensive time, rendering the contaminated zone virtually uninhabitable in the interim.
Below is a list of five different types of bombs based on the fundamental explosive mechanism they employ.
Compressed gas
Relatively small explosions can be produced by pressurizing a container until catastrophic failure such as with adry ice bomb. Technically, devices that create explosions of this type can not be classified as "bombs" by the definition presented at the top of this article. However, the explosions created by these devices can cause property damage, injury, or death. Flammable liquids, gasses and gas mixtures dispersed in these explosions may also ignite if exposed to a spark or flame.
Low explosive
The simplest and oldest bombs store energy in the form of alow explosive.Black powder is an example of a low explosive. Low explosives typically consist of a mixture of an oxidizing salt, such aspotassium nitrate (saltpeter), with solid fuel, such as charcoal or aluminium powder. These compositions deflagrate upon ignition, producing hot gas. Under normal circumstances, thisdeflagration occurs too slowly to produce a significant pressure wave; low explosives, therefore, must generally be used in large quantities or confined in a container with a high burst pressure to be useful as a bomb.
High explosive
A high explosive bomb is one that employs a process called "detonation" to rapidly go from an initially high energy molecule to a very low energy molecule.[18] Detonation is distinct from deflagration in that the chemical reaction propagates faster than the speed of sound (often many times faster) in an intense shock wave. Therefore, the pressure wave produced by a high explosive is not significantly increased by confinement as detonation occurs so quickly that the resulting plasma does not expand much before all the explosive material has reacted. This has led to the development ofplastic explosive. A casing is still employed in some high explosive bombs, but with the purpose offragmentation. Most high explosive bombs consist of an insensitivesecondary explosive that must be detonated with ablasting cap containing a more sensitiveprimary explosive.
Thermobaric
Athermobaric bomb is a type ofexplosive that utilizes oxygen from the surrounding air to generate an intense, high-temperature explosion, and in practice theblast wave typically produced by such a weapon is of a significantly longer duration than that produced by a conventional condensed explosive. The fuel-air bomb is one of the best-known types of thermobaric weapons.
Nuclear fission
Nuclear fission type atomic bombs utilize the energy present in very heavy atomic nuclei, such as U-235 or Pu-239. In order to release this energy rapidly, a certain amount of the fissile material must be very rapidly consolidated while being exposed to a neutron source. If consolidation occurs slowly, repulsive forces drive the material apart before a significant explosion can occur. Under the right circumstances, rapid consolidation can provoke a chain reaction that can proliferate and intensify by many orders of magnitude within microseconds. The energy released by a nuclear fission bomb may be tens of thousands of times greater than a chemical bomb of the same mass.
Nuclear fusion
Athermonuclear weapon is a type of nuclear bomb that releases energy through the combination of fission andfusion of the light atomic nuclei of deuterium and tritium. With this type of bomb, a thermonuclear detonation is triggered by the detonation of a fission type nuclear bomb contained within a material containing high concentrations of deuterium and tritium. Weapon yield is typically increased with a tamper that increases the duration and intensity of the reaction through inertial confinement and neutron reflection. Nuclear fusion bombs can have arbitrarily high yields making them hundreds or thousands of times more powerful than nuclear fission.
Apure fusion weapon is a hypothetical nuclear weapon that does not require a primary fission stage to start a fusion reaction.
Antimatter
Antimatter bombs can theoretically be constructed, but antimatter is very costly to produce and hard to store safely.
Bunker buster – capable of penetrating hardened or fortified surfaces before detonating
Concrete bomb – contains dense, inert material (typically concrete) instead of explosives, using thekinetic energy of the falling bomb to destroy target
Thefirst air-dropped bombs were used by the Austrians in the 1849siege of Venice. Two hundred unmanned balloons carried small bombs, although few bombs actually hit the city.[19]
The first bombing from a fixed-wing aircraft took place in 1911 when the Italians dropped bombs by hand on the Turkish lines in what is nowLibya, during theItalo-Turkish War.[20] The first large scale dropping of bombs took place duringWorld War I starting in 1915 with the GermanZeppelin airship raids onLondon, England, and the same war saw the invention of the firstheavy bombers. One Zeppelin raid on 8 September 1915 dropped 4,000 lb (1,800 kg) of high explosives and incendiary bombs, including one bomb that weighed 600 lb (270 kg).[21]
DuringWorld War II bombing became a major military feature, and a number of novel delivery methods were introduced. These includedBarnes Wallis'sbouncing bomb, designed to bounce across water, avoidingtorpedo nets and other underwater defenses, until it reached adam,ship, or other destination, where it would sink and explode. By the end of the war, planes such as the allied forces'Avro Lancaster were delivering with 50 yd (46 m) accuracy from 20,000 ft (6,100 m), ten tonearthquake bombs (also invented by Barnes Wallis) named "Grand Slam", which, unusually for the time, were delivered from high altitude in order to gain high speed, and would, upon impact, penetrate and explode deep underground ("camouflet"), causing massive caverns or craters, and affecting targets too large or difficult to be affected by other types of bomb.
Modern militarybomber aircraft are designed around a large-capacity internalbomb bay, whilefighter-bombers usually carry bombs externally on pylons or bomb racks or on multiple ejection racks, which enable mounting several bombs on a single pylon. Some bombs are equipped with aparachute, such as the World War II "parafrag" (an 11 kg (24 lb) fragmentation bomb), theVietnam War-eradaisy cutters, and the bomblets of some moderncluster bombs. Parachutes slow the bomb's descent, giving the dropping aircraft time to get to a safe distance from the explosion. This is especially important with air-burstnuclear weapons (especially those dropped from slower aircraft or with very high yields), and in situations where the aircraft releases a bomb at low altitude.[22] A number of modern bombs are alsoprecision-guided munitions, and may be guided after they leave an aircraft by remote control, or by autonomous guidance.
A bomb may also be positioned in advance and concealed.
A bomb destroying arail track just before atrain arrives will usually cause the train toderail. In addition to the damage to vehicles and people, a bomb exploding in atransport network often damages, and is sometimes mainly intended to damage, the network itself. This applies torailways,bridges,runways, andports, and, to a lesser extent (depending on circumstances), to roads.
In the case ofsuicide bombing, the bomb is often carried by the attacker on their body, or in a vehicle driven to the target.
TheBlue Peacock nuclear mines, which were also termed "bombs", were planned to be positioned during wartime and be constructed such that, if disturbed, they would explode within ten seconds.
The explosion of a bomb may be triggered by adetonator or afuse. Detonators are triggered byclocks,remote controls likecell phones or some kind of sensor, such as pressure (altitude),radar, vibration or contact. Detonators vary in ways they work, they can be electrical, firefuze or blast initiated detonators and others,
Blast seat
Inforensic science, the point of detonation of a bomb is referred to as its blast seat, seat of explosion, blast hole orepicenter. Depending on the type, quantity and placement of explosives, the blast seat may be either spread out or concentrated (i.e., anexplosion crater).[23]
Other types ofexplosions, such asdust orvapor explosions, do not cause craters or even have definitive blast seats.[23]
^abcdNeedham, Joseph. (1987).Science and Civilization in China: Volume 5, Chemistry and Chemical Technology, Part 7, Military Technology; the Gunpowder Epic. Cambridge University Press. pp. 170–174.
^Delgado, James (February 2003)."Relics of the Kamikaze".Archaeology.56 (1). Archaeological Institute of America.Archived from the original on 2013-12-29.
^Marks, Michael E. (2002).The Emergency Responder's Guide to Terrorism. Red Hat Publishing Co., Inc. p. 30.ISBN1-932235-00-0.
^Wong, Henry (2002). "Blast-Resistant Building Design Technology Analysis of its Application to Modern Hotel Design". WGA Wong Gregerson Architects, Inc. p. 5.
^Coupland, R.M. (1989). Amputation for antipersonnel mine injuries of the leg: preservation of the tibial stump using a medial gastrocnemius myoplasty. Annals of the Royal College of Surgeons of England. 71, pp. 405–408.
Andrade, Tonio (2016),The Gunpowder Age: China, Military Innovation, and the Rise of the West in World History, Princeton University Press,ISBN978-0-691-13597-7.
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