Bomb is a weapon that explodes. Bombs have been used chiefly in warfare, though terrorists also use them. Bombs kill or injure people and destroy buildings, airplanes, ships, and other targets. Most bombs consist of a metal case filled with explosives or chemicals and a means of exploding or scattering the contents. Some bombs are small enough to be carried by hand. Terrorists often use such bombs. In warfare, small bombs may be thrown as grenades or fired from artillery. However, most bombs are large and dropped from airplanes.
Bombs dropped from planes are considered gravity weapons because Earth's attraction pulls the bombs downward. Missiles, which fly under their own power, are sometimes said to carry bombs. However, warhead is the correct term for the explosive part of a missile.
Bombs dropped from the air have small tail wings called fins. The fins stabilize the bomb and make it fall on a more predictable path. Bombs released from low-flying planes may have small panels called retardation devices that open to slow the bomb down. The plane can then fly from the area before the bomb explodes. Parachutes are sometimes used to slow a falling bomb, especially a nuclear weapon.
A device called a fuse triggers most bomb explosions. Bombs with contact fuses explode when the bomb strikes a target. Bombs with proximity fuses explode a short distance above the ground. One type of proximity fuse uses radar to measure the distance from the ground. Another type reacts to increases in air pressure as the bomb nears the ground. A delay fuse can be set to explode the bomb minutes or hours after it hits the ground. This type of fuse makes it difficult for the enemy to clear the wreckage from a bombing attack.
There are two main categories of bombs. They are (1) conventional bombs and (2) nuclear bombs.
