A bomb is a hollow case filled with explosive or other destructive chemicals and exploded by percussion or a timing device. The outer case may be metal, plastic, concrete, or glass; the shape, size, and contents of a bomb depend on its application.
The term bomb was first applied to the short-barreled cannons of the 14th century, which were known as bombards; because the cast iron or stone shot fired from these weapons was lobbed upward in a high arc, the word bomb is still used to refer to the ammunition fired from mortars, where the projectile follows a high trajectory. More commonly, the word bomb refers to a hollow-cased projectile delivered from the air by an aircraft or a rocket. Sometimes bombs are designed to be placed in position or thrown by hand.
Development of bombing
Shortly after balloons were invented in 1783, attempts were made to deliver bombs from the air. In 1849, during the Austro–Venetian War, the Austrians loaded paper hot-air balloons with small bombs fitted with time fuses and released them so that they drifted toward Venice. Reports say they caused more psychological than material damage.
Strangely enough, the ingenious idea re-appeared in the autumn of 1944. The Japanese released on the easterly winds about 1,000 hydrogen-filled paper balloons, each 33 ft. (10 m) in diameter and loaded with a small antipersonnel or incendiary bomb. They were carried toward the United States and Canada, but most fell in remote areas and only 300 or so were recovered.
Throughout the 19th century, there were attempts to use balloons to bomb enemies, but the practice stopped in 1899 when it was forbidden by the Hague Convention. In December 1903, the Wright brothers made their first successful flight in a heavier-than-air machine, and in 1907 the Hague restriction was dropped. Many countries, but mainly the United States and Italy, then began experimenting again with bombs dropped from the air.
The earliest recorded bomb dropping from aircraft was by the Italians in their campaign against the Turks. On November 1, 1911, Lieu-tenant Gavotti of the Italian army dropped four 4.5 lb. (2 kg) bombs, converted Spanish hand grenades, on the Turkish encampment at Ain Zara in Libya. Although the Turks protested, the Italians quickly pointed out that they had shortly before bombarded the camp with 152 naval shells without eliciting any form of protest. Inevitably, this started a discussion on the ethics of air bombardment. Bombing techniques improved steadily and the advantages over the gun—increased range and greater projectile weight—were realized. During World War I, when both airships and airplanes were used, German zeppelins made more than 200 flights over London, dropping some 200 tons (180 tonnes) of bombs and killing or wounding 1,700 people. In 1923, draft rules for air warfare were drawn up but never ratified.
By the end of World War II, the Allies had dropped about 2 million tons of bombs on Germany and German-occupied territory, and although there has since been much controversy over its value, air bombardment has continued to play a large part in all subsequent conflicts. Nearly 7 million tons (6 million tonnes) of bombs were dropped by the United States on Indo-Chinese targets between 1965 and 1973. The use of so-called smart bombs in the Gulf War and during the Balkans crisis in the 1990s played a strategic part in avoiding ground troop losses and civilian casualties but reopened the debate on sustained bombing as a means of resolving conflict.
The early aerial bombs were ordinary shells with fins and new fuses added. Because they were primed by eye and hand-launched, they tended to be small, about 25 lbs. (11 kg), and inaccurate. During and after World War I, great improvements were made. Mounting racks and aiming devices were fitted to aircraft, and a variety of special-purpose bombs appeared: fragmentation, incendiary, chemical, illuminating, and so on. That bombing had become an important part of warfare was amply demonstrated in the Spanish Civil War (1936–1939) by the German contingent, who gained much practical experience there.
In World War II, despite the development of more lethal bombs, the major problem was accuracy. Techniques were developed, such as the use of radio beacons to fix targets and illuminating flares for night bombing. A recent improvement in accuracy is the use of lasers to guide the bomb, which enables pin-point targets to be hit with certainty. This system was successfully used in 1971 by the United States in Vietnam.
Bombs that carry their own aiming devices—such as infrared or magnetic seekers—have also been developed, with an emphasis on maximizing stability, range, and accuracy.
