# What is the difference between an atomic bomb and a nuclear/hydrogen bomb? **URL:** \ **Category:** Factual Questions\ **Created:** [August 9, 2004, 9:36pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-an-atomic-bomb-and-a-nuclear-hydrogen-bomb/259099 "2004-08-09T21:36:21Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![bummerboy](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bummerboy](https://boards.straightdope.com/u/bummerboy)\ **Post date:** [August 9, 2004, 9:36pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-an-atomic-bomb-and-a-nuclear-hydrogen-bomb/259099/1 "2004-08-09T21:36:21Z")
Fission and fusion? ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [August 9, 2004, 9:49pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-an-atomic-bomb-and-a-nuclear-hydrogen-bomb/259099/2 "2004-08-09T21:49:24Z")
Have you considered consulting a dictionary or online encyclopedia? ---
**Author:** ![bummerboy](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bummerboy](https://boards.straightdope.com/u/bummerboy)\ **Post date:** [August 9, 2004, 10:39pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-an-atomic-bomb-and-a-nuclear-hydrogen-bomb/259099/3 "2004-08-09T22:39:28Z")
Ahh, nevermind, Cecil already had [one](http://www.straightdope.com/classics/a960112b.html) I was right, fission and fusion ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [August 9, 2004, 11:54pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-an-atomic-bomb-and-a-nuclear-hydrogen-bomb/259099/4 "2004-08-09T23:54:58Z")
Sort of. Nuclear=atomic=fission, usually. You could call a fusion bomb by both these names, as well. Hydrogen = fusion. ---
**Author:** ![JohnM](https://avatars.discourse-cdn.com/v4/letter/j/848f3c/32.png) [@JohnM](https://boards.straightdope.com/u/JohnM)\ **Post date:** [August 10, 2004, 12:47am UTC](https://boards.straightdope.com/t/what-is-the-difference-between-an-atomic-bomb-and-a-nuclear-hydrogen-bomb/259099/5 "2004-08-10T00:47:17Z")
To elaborate further on what **Smeghead** said: atomic=nuclear=fission hydrogen=thermonuclear=fusion Plus, to make things more confusing, all fusion weapons have a fission trigger, and high-yield weapons are three stage, fission-fusion-fission. The primary, or trigger, in a two- or three-stage thermonuclear device may also be boosted with tritium for a higher yield. ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [August 10, 2004, 2:34am UTC](https://boards.straightdope.com/t/what-is-the-difference-between-an-atomic-bomb-and-a-nuclear-hydrogen-bomb/259099/6 "2004-08-10T02:34:51Z")
Here ya go: the [binding energy per nucleon curve](http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin.html) (scroll down a little bit for the graph). (“Nucleon” is a generic name for either neutrons or protons – the particles that give an atom the lion’s share of its atomic mass). At the peak of the graph is iron. It’s subatomic particles have the most “binding energy” per particle, meaning that it is the most tightly bound. In general, any change that causes subatomic particles to become more tightly bound will release energy. What this translates to is that if you convert atom(s) on a low part of the curve (relative to the vertical axis), to atom(s) on a higher part of the curve, you get some energy. Said in another way, if you convert atoms that are far in mass from iron to atoms that are closer in mass to iron, you get energy out. Reactions that combine atoms to make heavier atoms are fusion; these can be plotted on the graph as movement from left to right since the horizontal axis measures atomic mass. Reactions that split heavier atoms into lighter atoms are fission; these can be seen as movement from right to left on the graph. It boils down to this: If you can travel on the curve from a low spot to a high spot, you get energy out. As you can see, there is a huge amount of energy to be had by converting atoms on the far left to atoms closer to iron. This is fusion. There is a much smaller (but not insignificant) amount of energy to be had by converting very heavy things on the right to lighter elements that are closer to iron. This is fission. ---
**Author:** ![N9IWP](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/n9iwp/32/3154_2.png) [@N9IWP](https://boards.straightdope.com/u/N9IWP)\ **Post date:** [August 10, 2004, 3:30am UTC](https://boards.straightdope.com/t/what-is-the-difference-between-an-atomic-bomb-and-a-nuclear-hydrogen-bomb/259099/7 "2004-08-10T03:30:46Z")
Wow, [sup]62[/sup]Ni has the most binding energy. Always thought it was Iron. [http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin2.html#c1](http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin2.html#c1) Brian