nuke bomb explosion
Weapons and Kit

How Did The Atomic Bomb Work?

nuke bomb explosion

The UK's nuclear arsenal is set to benefit from increased funding, announced as part of the Integrated Review by Prime Minister Boris Johnson. 

It has been described as the "biggest review of our foreign, defence, security and development policy since the end of the Cold War".

When the USA dropped an Atomic Bomb over the Japanese city of Hiroshima on August 6, 1945, a culmination of several years’ work by the brightest minds on the planet was realised. At that time, the bomb was the most powerful weapon ever created and it wreaked devastation the likes of which had never been seen. It had been a race. A race that in the final months of the war had become a single-entry competition following the dropping out of the Germans with the fall of the Third Reich in May 1945. The challenge that was left for the Americans was one of creating the weapon before, as they saw it, considerably more Allied lives were lost fighting a war in the frequently difficult environment of the Far East. 

In August 1945, President Harry Truman had the means to settle the war … and he used them.

But How Did 'The Bomb' Work?

Here, BFBS looks at the science behind creating an Atomic Bomb. But, for those who think this is a feat achievable in your garden shed, think again, the materials required to create a nuclear weapon are some of the most controlled on the planet.

atomic bomb animation

The Basics

The fundamental basic principle in the creation of an Atomic Bomb is Albert Einstein’s law of relatively.

E = mc²

In the most layman terms, this means matter equals energy and therefore, each can be transferred to the other … matter can become energy and energy can become matter.

A basic example of this is heating water (matter) until it turns into steam (energy) and vice versa.

The matter in question for the Atomic Bomb is Uranium and turning that into energy is essentially what the weapon achieved when it detonated on August 6, 1945.

The Specifics

To create the explosive yield recorded at the atomic bombing of Hiroshima, the scientists behind the weapon used just 600 milligrams of Uranium.

This is about the same weight as a ten pence piece.

From that small amount of matter, enough energy to kill 140,000 people was created. But how?

As discussed earlier, the unleashing of this energy lay in the splitting of the atom.

The process of which is called fission.

reaction diagram


Fission is all about splitting atoms into smaller pieces. As this occurs, literally as the atom splits into two, a cast-off bit of matter called a neutron collides with other pieces of the atom. As the atom splits, it releases energy, and so as the process continues, more and more energy is created.

This is called, like the 1985 pop hit by Diana Ross, a 'chain reaction'.

The atoms of uranium are continually being split by the cast-off neutrons resulting in the production of energy (an explosion).

In a controlled environment this ‘chain reaction’ producing energy can be most helpful … this is what a nuclear power station is.

But in an uncontrolled environment, the resulting energy can be devastating … this is what a nuclear bomb is.

What Else?

Uranium is not the only matter capable of achieving this. Also able to unleash terrific energy is Plutonium. Both these materials are highly radioactive, which basically means they give off neutrons capable of splitting atoms, generating energy.

bomb drawing

What Causes A Chain Reaction?

To create the chain reaction and resulting release of energy (explosion), some uranium has to be brought into violent contact with more uranium. In a bomb, like the one used at Hiroshima, this is achieved when Uranium is fired into a separate piece of Uranium at great speed, like a bullet from a gun.

The resulting impact creates the required chain reaction and there you have your nuclear explosion. Simple.

So, what are you amateur physicists waiting for?

Note: we are not really encouraging you to go into the garage and attempt a nuclear bomb. The uranium and plutonium required is heavily controlled and regulated by the International Atomic Energy Agency and safeguards afforded under the Nuclear Non-proliferation Treaty.

Maybe stick to building model rockets in the garage instead …

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