The Encyclopedia
of Differences

Difference Between Atomic and Nuclear Bomb

Table of Contents

The main difference between an atomic bomb and a nuclear bomb is that the term "nuclear bomb" refers to all explosives that produce massive energy from nuclear reactions, whereas atomic bombs are considered as a sub-category of nuclear bombs.

In other words, all atomic bombs are nuclear bombs, but not all nuclear bombs can be considered as atomic bombs.

What are Nuclear Bombs?

tsar bomba
Tsar Bomba, the Soviet Union's most powerful Nuclear Bomb ever created and tested

Nuclear bombs create explosions that release massive amounts of energy from nuclear fission or fusion. Usually, chemical reactions take place through the exchange or sharing of electrons.

Nuclear reactions differ from this because they result in creating a chemical species by altering the nucleus of the reactants. A nuclear reaction is done through nuclear fission or fusion, in which nuclei are either split or merged respectively. These reactions are frequently chain reactions that repeatedly occur once activated.

There are mainly two categories of nuclear bombs, atomic and hydrogen bombs. Atomic bombs are born from nuclear fission, while hydrogen bombs use fusion reactions.

Hydrogen bombs are also known as thermonuclear weapons due to the large amount of activation energy they require.

What are Atomic Bombs?

little boy atomic bomb
Little Boy, the codename of the Atomic Bomb dropped by the United States on Hiroshima on 6 August 1945

Atomic bombs are explosives that produce energy specifically through nuclear fission. Nuclear fission is a phenomenon that occurs when a nucleus is split into two other atoms half its size. Plutonium-239 and Uranium-235 are used; these are known as primary fissionable materials.

Nuclear fission was first discovered by German nuclear physicists Otto Hahn, Lise Meitner, and Fritz Strassman in 1938. Later, the United States of America weaponized this discovery to create the first atomic bomb during World War II.

Theoretical physicist J. Robert Oppenheimer is known as the “father of the atomic bomb.” The first-ever atomic bomb was tested in a deserted area in New Mexico in 1945. It was known as the Trinity Test.

Differences between Atomic and Nuclear Bombs 

Source of Energy

Both bombs stem from nuclear reactions. As previously stated, fission and fusion can occur in nuclear bombs, whereas atomic bombs are only those which produce energy through fission.

Fission occurs automatically, and a massive amount of energy is produced through a chain reaction. This occurs when a neutron strikes principal fissile material, splitting the nucleus into two.

The reaction results in the release of thermal energy, gamma radiation, and a few stray neutrons. These stray neutrons then strike more fissionable material, producing more fission reactions.

On the other hand, nuclear bombs are created through fusion reactions. Two light-weight atoms are combined to make a new chemical species. Usually, Tritium and Deuterium are combined to form Helium. This type of bomb is also called a hydrogen bomb (since Tritium and Deuterium are hydrogen isotopes).

Nuclear bombs can also be multi-stage explosives that perform both fission and fusion reactions consecutively.

Amount of Energy Involved

Some nuclear bombs differ from atomic bombs in terms of efficiency and amount of energy involved. As mentioned previously, atomic bombs require little energy to split atoms; this is not the case for other nuclear bombs such as hydrogen bombs.

Hydrogen bombs often require extremely high temperatures and a large amount of energy to trigger them. Therefore we use fission reactions to provide the needed activation energy for such nuclear bombs.

Not only that, but other nuclear bombs also differ from atomic bombs relative to the amount of energy released. Hydrogen bombs are much more efficient and release a higher amount of energy than atomic bombs.

Tested Vs Used 

Almost all nuclear bombs are tested, but only atomic bombs have been used. The United States used these weapons of mass destruction during World War II on Hiroshima and Nagasaki.

The Little Boy and The Fat Man were both atomic bombs used by the US. They had a blast radius of roughly 1.6km and killed around 160,000-200,000 people in total. This was the only time a nuclear weapon was used.

On the other hand, hydrogen bombs have only been tested so far. In 1961 the Soviet Union tested the Tsar Bomba, the largest nuclear weapon ever exploded.

Comparison Chart: Atomic Bombs Vs Nuclear Bombs

FeaturesAtomic BombsNuclear Bombs
Source of EnergyNuclear fissionNuclear fission, nuclear fusion or both
Amount of energy needed for activation/releasedA little amount of energy is needed for activation while energy released is less than that in other nuclear bombsA massive amount of energy is needed for activation and the amount of energy released is more than that in atomic bombs
Tested or UsedTested & usedTested

Similarities Between Atomics and Nuclear Bombs

There are quite a few similarities between atomic bombs and other nuclear bombs. For one, they’re both based on nuclear reactions, as atomic bombs are a sub-category of nuclear bombs. 

Other than that, all nuclear bombs produce a signature mushroom cloud when they explode. All nuclear bombs also have an extremely large blast radius and can cause massive destruction. Leftover radiation and fallout from the bomb is also a common after-effect of all nuclear bombs.

The Nuclear Non-Proliferation Treaty (NPT)

Around nine countries worldwide possess nuclear weapons. The Treaty on the Non-Proliferation of Nuclear Weapons, which came into effect in 1968, was made to halt the spread of nuclear weapons worldwide.

According to the treaty, no country possessing nuclear weapons can help another country develop its nuclear program while slowly depleting its stock of nuclear weaponry.

Although Russia, the USA, China, and France have always been a part of the treaty, Pakistan, South Sudan, Israel, India, and North Korea are the five nuclear countries that are still not members.

It is estimated that around 13,000 nuclear weapons are currently present worldwide, some of which are 3000 times as powerful as that dropped on Hiroshima.


How long do radiation and fallout last?

Fallout radiation tends to decay quickly. The area would be safe to travel to within 3-5 weeks. For the survivors, lingering radiation could be a hazard for up to 5 years.

Are hydrogen bombs more powerful than atomic bombs?

Yes, hydrogen bombs are more powerful than atomic bombs.

How many tons of TNT is an atomic and hydrogen bomb equivalent to?

Atomic bombs dropped on Hiroshima and Nagasaki were the equivalent of 15,000-21,000 tons of TNT. In comparison, a hydrogen bomb could be equivalent to several megatons of TNT.


It’s not so easy to draw a contrast between nuclear and atomic bombs, especially since the atomic bomb is a type of nuclear bomb in itself. Nuclear bombs are a wide variety of bombs that can stem from fission or fusion reactions, whereas atomic bombs result from only fission reactions.

Hydrogen bombs are another type of nuclear bomb. These are much more powerful and destructive than atomic bombs and require a higher amount of activation energy.

The common goal for humanity is to never use nuclear weapons, especially after the destruction seen in Hiroshima and Nagasaki. The NPT is a step towards that, but as countries continue to threaten each other with their nuclear arsenal, we can only pray that we stay safe.

Feel free to comment and discuss about the article in the comment space below if you have any information or remarks to add. If you think we made a mistake, you can also report it there.
Share our Article on:

Table of Contents

About the Author: Tom Vincent

Tom Vincent graduated with a bachelor's degree in economics and social studies. He then started his higher education at the University of François Rabelais in Tours with a DUT Information Communication. To expand his knowledge, he also followed a professional degree in e-commerce and digital marketing at the Lumière University of Lyon. On this project, he is in charge of articles covering language, industry and social.
All Posts Written By Tom Vincent

Leave a Reply

Your email address will not be published. Required fields are marked *

magnifiercrosschevron-downarrow-right linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram