The blast from an atomic bomb’s explosion will last for only one-half to one second. 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 creates dynamic pressure. These two tremendous forces are what destroys everything in the area of the epicenter. The blast pressure and fireball together only last for approximately eleven seconds, but because it contains 50% of the atomic bomb’s latent energy, a great deal of damage is done.

In Hiroshima the blast from the atomic bomb was measured to be about four and a half to six 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. The static overpressure in Hiroshima caused 91% of all the buildings to be destroyed, while in Nagasaki it caused 36% of all of the buildings to be 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 happen when people are hit with glass fragments that are flying through the air. The total number of people affected in Hiroshima was approximately seventy-eight thousand, while in Nagasaki the total number affected was approximately forty-five thousand.

The thermal radiation produced by an atomic bomb explosion will account for 35% of the atomic bomb’s damage. Thermal radiation can come in 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. These flash burns are produced by the flash of thermal radiation right after the explosion. Flash burns can be either first degree burns (bad sun burns), second degree burns ( blisters, and infections), or third degree burns (chared flesh). The second type is known as flame burns. These are burns that come from one of two different types of fires, which are created when flammable materials are ignited by the thermal radiation. The first type is called firestorms. A firestorm is violent, has raging winds, and has extremely high temperatures; but fortunately it does not spread very rapidly. The second type is called a conflagration. A conflagration is when the fire spreads in a front, almost like the forest fires in California. The thermal radiation produced by the atomic bomb’s explosion will account for most of the deaths or injuries.

In Hiroshima and Nagasaki the thermal radiation accounted for approximately 20% - 30% of the deaths or injuries from the atomic bomb’s explosion. Those that were at a distance of 4.2 kilometers from the hypocenter received first degree burns. Those that were at a distance of 3.5 kilometers from the hypocenter received second degree burns. Those that were at a distance of less the 1 kilometer from the hypocenter received third degree burns. 95% of the burns created from the thermal radiation were by flash burns, and only 5% of the burns were by flame burns. The reason for this low number of flame burns is that only 2% - 10% percent of the buildings caught on fire. By combining the damage from both the flash and flame burns one can begin to see the effects that an atomic bomb’s thermal radiation had. Approximately sixty thousand in Hiroshima, and approximately forty-one thousand people were either killed or injured from the thermal radiation.

The final effect that an atomic bomb caused is the nuclear radiation produced from the fission process. The nuclear radiation comes in the form of either Gamma rays or Beta particles. Gamma rays are electromagnetic radiation originating in the atomic nuclei, physically identical to x-rays. They can enter into living tissue extremely easily. Beta particles are negatively charged particles, identical to an electron moving at a high velocity. These forms of nuclear radiation are measured in rads (radiation-absorbed-dose), which is defined as the absorption of five ten millionths joule per gram of abosorbing material. During the initial nuclear radiation mostly Gamma rays are emitted from the fireball. This period of initial nuclear radiation lasts for approximately one minute. During the residual nuclear period (fallout) the Beta particles and more of the Gamma rays are emitted. The residual radiation has two stages: early fallout and delayed fallout. In early fallout, the heavy and highly radioactive particles fall back to the earth, usually within the first twenty-four hours. In delayed fallout, the tiny and often invisible particles fall back to the earth, and usually last from a couple of days to several years. The nuclear radiation from the atomic bomb’s explosion was not the main cause of death, but it did still have serious results(Feinburg,p.10-13).