An atomic bomb is so called because the explosion is created by splitting atoms,
and the power that is produced from one atomic bomb can as we know, destroy an entire city.

The atomic bomb was brought to world attention on Monday, August 6, 1945 at 08:15 am, when an atomic bomb called 'LittleBoy' yielding 14.5 kilotons of explosive power was dropped on Hiroshima, Japan from an American B-29 bomber Enola Gay.

The explosion initially killed around 80,000 people and finally killing another 60,000 due to their injuries and the acute radiation sickness. Approximately 70% of the city's buildings were completely destroyed, and 30% severely damaged.

 Japan initially did not believe that the USA had anymore than one bomb due to the complexity of their construction, so 3 days later on August 9, 1945 at 11:02 am,  a second atomic bomb called 'Fatman' which was a plutonium-239 bomb yielding 23.5 kilotons of destructive power was dropped on Nagasaki. (actual photo seen above)  It initially killed 75,000 with another 75,000 dying later due to radiation sickness and other injuries.  Japan now believed that the USA could have a whole arsenal of these new terrifying weapons and Emperor of Japan Hirohito ordered the surrender of his country a few days later and World War Two was effectively over.

Below is a modest image of the Fatman bomb that was 5 feet in diameter, 2 feet long, and weighed 10,300 lb.

To say that the entire city Hiroshima was turned into a  giant car park by the atomic blast may sound immature, except that it was true as the photo below testifies.

The youtube film below depicts an accurate representation of the atomic bomb that fell onto Hiroshima.

The atomic bomb was developed by American scientist J.R. Oppenheimer, who along with other scientists detonated the first atomic bomb at the Trinity test site near Alamogordo, New Mexico, on July 16, 1945. The test proved to  the United States government that such weapons were possible and indeed unimaginably powerful.  The economics were also just as appealing, one plane dropping one bomb to destroy one whole city.

Below is a photo of the very first atomic explosion at Trinity, it was that hot in the vicinity of the blast that the sand fused together into fragments of radioactive green jade which is similar to a dirty and rough bubbly type of glass

J.R. Oppenheimer was a professor of physics and director of science during the Manhattan Project which was America's program to develop this atomic bomb and indeed, develop it before anyone else did.  The atomic bomb was devised and developed at the secret military scientific research station at Los Alamos Laboratory in New Mexico.

" The Father of the A-Bomb "  Oppenheimer in full understanding and appreciation of this new terror weapon he had created famously quoted a passage from the Indian religious scripts Bhagavad Gita when he said "If the radiance of a thousand suns were to burst at once into the sky, that would be like the splendour of the mighty one." he then added " And Now I am become Death, the destroyer of worlds."

However, unbeknown to the Americans at the time, there was a network of Soviet agents working right in the heart of the program as part of the atomic bomb development team  and every single piece of technical information, blueprints, sketches and diagrams about the A-bomb found its way into Russian hands.  It was because of these spies that almost every developed country in the world finally got their hands on the A-bomb.  After which, the world then became a most unstable place with the possibility of nuclear war never being too far away.

Below is the list of spies that gave the Russians all the secrets on the A-Bomb.

Treason charges and the death penalty were not applicable to most of these spies, since the United States and the Soviet Union were supposed to be allies at the time.

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My explanation below of how an atomic bomb works is at a basic level, obviously it is more complex than this, but this is the general idea...

For an atomic bomb to explode there has to be a chain reaction from fast moving atoms that break apart in a collision, and plenty of enriched uranium-235 is needed to compound a chain reaction.  In 1945 uranium-235 was exceedingly hard to produce, it is extracted from crude and basic uranium ore at a rate of 1 part per every 500.

When this more pure uranium is extracted, uranium-238 is the result.  However, this is still practically useless for an atomic bomb as its atoms wont split as desired when it is compressed.  A huge uranium enrichment laboratory was built at Oak Ridge, Tennessee, USA where a system of altering the uranium-238 was put into practise.  Using magnetic separation, the atomic isotopes of the uranium were successfully completed.  These isotopes were then subjected to a gas centrifuge to separate the lighter atomic element of uranium-235 from the junk uranium-238.

When all of this difficult and complex work was completed, the requirement was to test the theory behind atomic fission or splitting the atom. It was mathematically calculated that  a super massive explosion should occur when two  pure uranium-235 blocks of metal was disintegrated into each other, i.e. nuclear fission...

...basically, a large 33lb uranium-235 bullet is super accelerate ( fired ) down a barrel via the detonation of high explosives, but instead of the shell exiting from the barrel it slams into a metal block also made of uranium-235 that is sealed in at the other end.  The speed of the collision is about 4 miles per second.

Below: The basic concept of the A-Bomb, using the "LittleBoy" atomic bomb as dropped on Hiroshima, to illustrate.

When this collision happens the uranium shell and the uranium block are compressed almost into infinity due to the massive force of the impact.  The atoms cannot compress any more so therefore there is only one way to go and that's to expand back out.  When this occurs, the uranium  has reached a stage called super critical mass.

The 'Fatman' atomic bomb used plutonium-239 and instead of firing the plutonium down a barrel it was centred in a sphere with the explosives all around the outside so that the plutonium was compressed in the middle when detonated.

Either way, the atoms now reverberate amongst one another and this continues creating a chain reaction of impacts and eventually  the atoms break apart, otherwise know as splitting the atom, all occurring in millionths of a second.

At least one neutron from each impact strikes another Uranium-235 nucleus and initiates nuclear fission, thus the chain reaction is sustained.

Therefore, when these atoms split, (not just one atom but billions of them) the universal force of nature that held them together releases massive amounts of stored neutron energy and that's when we get the atomic explosion.

The atomic bomb is detonated via an altitude set barometer fuse so that it explodes about 1850 feet (+/- 100 feet) from the ground, this amplifies the force even more as a downward blast that impacts and spreads the devastation further.

It isn't just metals that get compressed, they also experimented with gases, the most renown being hydrogen, and when fission is applied to this element the title of 'Hydrogen bomb' is given along with its explosive properties that are then labelled as thermonuclear, due to the fantastic heat that is generated.  It has been calculated that the initial explosion of a H-bomb reaches temperatures that are similar to the surface of the Sun.

The explosive power can be onwards and upwards to the equivalent of ½ million tons of dynamite exploding.  With the appliance of science and the improvement of the principles of fission along with different materials much larger yielding bombs have over the past several decades been created.

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