A brief history of the Atomic Bomb
Created | Updated Feb 23, 2005
Introduction
The atomic bomb is a nuclear device that when detonated releases energy equivalent too many 1000's of tons of conventional explosives. The atomic bomb is scientifically called a nuclear fission bomb as it uses the energy released in the process of nuclear fission to cause the detonation of the device.
History
The first atomic bomb was developed, built, and tested by the United States of America, in what was known as the Manhattan Project - launched in 1942. The project's leading scientist was J. Robert Oppenheimer, an American physicist who was born in 1904. The first atom bomb 'Gadget' was exploded at Alamogordo, New Mexico on July 16th 1945. The atom bomb was used for the first time in anger in 1945, when two bombs, code named 'Little Boy' and 'Fat Man' where dropped on the Japanese cities of Hiroshima and Nagasaki on August the 6th and August 9th respectively. With the immediate result that Japan surrendered unconditionally, thus ending the Second World War. The atomic bomb was however made obsolete in 1953 when Hydrogen bomb was developed. This device used the opposite to nuclear fission which is nuclear fusion which was much more powerful.
How it works
Fission and Chain Reactions
The atomic bomb works by causing a chain reaction using nuclear fission. Nuclear fission is possible because of the peculiar characteristics of certain heavy elements, such as Uranium or Plutonium. When an atom of one of these elements is hit by a neutron, it breaks up into lighter elements, whilst at the same time emits neutrons itself, these neutrons go on to split further atoms, and the process continues. With each release of neutrons, there is also an enormous release of energy, which is the reason for the incredible output of nuclear chain reactions.
The Design of the first A-Bombs
There are two basic design concepts for atomic weapon construction.
The implosion device; as used for Gadget1 and Fatman2, wherein a sphere of approximately 6kg of Plutonium was surrounded by conventional high explosives. The relatively large surface area of a sphere kept the plutonium from reaching super-criticality. In the hollow centre of the sphere was an initiator - the initiator was used to produce neutrons, in effect to 'kick start' the chain reaction within the plutonium. The initiator itself was a beryllium shell. Beryllium having the peculiar property that when subjected to alpha radiation it emits neutrons. The shell was then coated in Gold plating, to isolate it from stray alpha particles and in its centre was a minute quantity of polonium - a radioactive element and alpha particle source.
Effects
Blast Effects
The effects of an atomic blast come in three ways.
The first effect is the effect of the blast itself. The rapid expansion of the bomb material causes a shock wave which damages buildings and structures in two ways, first by being hit by shock wave itself, which is like hitting everything with giant sledge hammers and then being blown back the other way by extreme wind. This is caused by air rushing back to fill the vacuum left by the shock wave.
Thermal Effects
The second effect is the Thermal effect, which is caused by the fireball the bombs explosions creates. This causes heat radiation to be spread over a vast area although the farther away you go the less effective the heat flash is. For example up to 32 kilometers from the site of a 10-megaton blast bare skin would suffer 2nd degree burns and 64 Kilometers away only first degree burns. This flash also ignites dry flammable materials like paper and certain fabrics causing fires, which is why they often spread in urban area. In Certain condition s these small fires can even combine to form giant firestorms.
Radiation Effects
The third effect is the radiation a bomb releases. This radiation comes in two forms called prompt radiation, which is the sudden bust of radiation the bomb gives out like the heat radiation flash and fallouts. Fallout is where the radioactive atoms created when the uranium or plutonium is split get mixed in with the material in the mushroom cloud produced by the bomb and then rain back down over a large area increasing the normal background radiation to dangerous levels.
The radiation produced by an atomic bomb is a mixture of gamma rays and more neutrons, which is called beta particle radiation. Beta particles are the least dangerous as they can be blocked by a sheet of aluminum but gamma rays can penetrate thick lead. There are to main effects of radiation on a human being. First is a person can suffer radiation poisoning or the radiation can cause damage to cells DNA causing cancer.
