Atomic Bomb

Atomic Bomb

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


The blast from an atomic bombís 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 bombís latent energy a great deal of destruction

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