During wartime, horrible atrocities against all of humanity must be dealt with. Crimes against humanity, as never witnessed before, and hopefully to never be seen again, occurred during the course of World War II. America has always, and most likely will always place a high value on American lives. In order to protect these lives and to insure that the world is safe for democracy, American leaders had to make a very tough decision, whether or not to drop the atomic bomb on Japan. This act would essentially trade Japanese lives for American lives. The Japanese were responsible for hundreds of thousands of American casualties in the Pacific, including the unprovoked attack on Pearl Harbor. With Japanese forces showing no signs of surrender, American leaders made a decision. This decision essentially changed the history of warfare forever.
An atomic bomb is any weapon that gets its destructive power from an atom. This power comes when the matter inside of the atoms is transformed into energy. The process by which this is done is known as fission. The only two atoms suitable for fission are the uranium isotope U-235 and the plutonium isotope Pu-239. Fission occurs when a neutron, a subatomic particle with no electrical charge, strikes the nucleus of one of these isotopes and causes it to split apart. When the nucleus is split, a large amount of energy is produced, and more free neutrons are also released. These neutrons strike other atoms, which causes more energy to be released. If this process is repeated, a self-sustaining chain reaction will occur, and it is this chain reaction that causes the atomic bomb to have its destructive power.
The first type of atomic bomb ever used was a gun-type. In this type two subcritical pieces of U-235 are placed in a device similar to the barrel of an artillery shell. One piece is placed at one end of the barrel and will remain there at rest. The other subcritical mass is placed at the other end of the barrel. A conventional explosive is packed behind the second subcritical mass. When the fuse is triggered, a conventional explosion causes the second subcritical mass to be propelled at a high velocity into the first subcritical mass. The resulting combination causes the two subcritical masses to become a supercritical mass. When this supercritical mass is obtained, a rapid self-sustained chain reaction is caused. This type of atomic bomb was used on Hiroshima, and given the nickname ?Little Boy? after Franklin D. Roosevelt.
The second type of atomic bomb is an implosion bomb. In this type a subcritical mass, which is in the shape of a ball, is placed in the center of the weapon. This subcritical mass is surrounded in a spherical arrangement of conventional explosives. When the fuse is triggered all of the conventional explosives explode at the same time. This causes the subcritical mass to be compressed into a smaller volume, thus creating a supercritical mass to be formed. After this supercritical mass is obtained, a self-sustained chain reaction takes place and causes the atomic explosion. This type of atomic bomb was used on Nagasaki, and given the nickname ?Fat Man? after Winston Churchill.
The blast from an atomic bomb's explosion will last for only one-half to one second, but in this amount of time a great deal of damage is done. A fireball is created by the blast, which consists mainly of dust and gasses. The dust produced in this fireball has no substantial effect on humans or their environment. However, as the gasses expand a blast wave is produced. As this blast wave moves, it creates static overpressure. This static overpressure then in turn creates dynamic pressure. The static overpressure has the power to crush buildings. The dynamic pressure creates winds, which have the power to blow down trees. The blast pressure and fireball together only last for approximately eleven seconds, but because it contains fifty percent of the atomic bomb's latent energy a great deal of destruction occurs.
In Hiroshima, the blast from the atomic bomb was measured to be about four and a half to six and seven tenths tons of pressure per square meter, while in Nagasaki the blast was measured to be about six to eight tons of pressure per square meter. Because of this dramatic change in the pressure most of the cities were destroyed. The static overpressure in Hiroshima destroyed between sixty-two and ninety thousand buildings, while in Nagasaki all of the buildings within three thousand feet of the center of the blast were completely destroyed. The static overpressure created a dynamic pressure that had winds up to four hundred miles per hour. These winds caused minor scratches, lacerations, or compound fractures, which came about when people and glass fragments were projected through the air. By combining the results of the static overpressure and the dynamic pressure one can begin to see what damage was caused by the atomic bomb's blast.
The thermal radiation produced by an atomic bomb explosion will account for thirty-five percent of the atomic bomb's damage. Thermal radiation can come in one of three forms: ultraviolet radiation, visible radiation, or infrared radiation. The ultraviolet radiation is absorbed so rapidly by air particles that it has no substantial effect on people. However, the visible and infrared radiation creates an enormous amount of heat to be produced, approximately ten million degrees Celsius at the hypocenter. This heat has two main effects. The first is known as flash burns. The flash of thermal radiation produces these flash burns right after the explosion. Flash burns can be either first-degree burns (bad sun burns), second-degree burns (blisters, infections, and scars), or third-degree burns (destroyed skin tissue). The second type is known as flame burns. These are burns that come from one of two different ...