Key Difference: The primary difference between a Hydrogen Bomb and an Atomic Bomb is that an Atomic Bomb used nuclear fission of create the energy blast, whereas a Hydrogen Bomb uses nuclear fusion. A Hydrogen Bomb is far deadlier and dangerous than an Atomic Bomb.

The term Atomic Bomb or atom bomb tends to make people nervous and even scared, and with good reason. It is a devastating device that can kill millions of people in one go, and can level a whole city within seconds, not accounting for the years of radioactive radiation it leaves behind. It is not a power that anyone should have over someone else.

One of the largest atomic bombs developed has the destruction power of up to 500 kilotons of TNT. In comparison, the first ever atomic bomb used in warfare in Hiroshima, Japan in 1945 had a blast yield of 15 kilotons of TNT. While an atom bomb is bad, a hydrogen bomb is even worse. It is capable of much more damage than an atomic bomb. The most powerful hydrogen bomb developed till date has a blast yield of15000 kilotons, which is a thousand times worse than the first atom bomb. Technically speaking, there is no limit to the blast yield of a hydrogen bomb, which makes it even more dangerous.

Both are types of nuclear weapons, also colloquially known as weapons of mass destruction. Both are capable of great destruction; however they differ in the manner that they react in order to bring about this said destruction. The atomic bomb is a type of fission based nuclear weapon, which basically means that it uses a fission reaction to create heat and energy. Here, the energy is created by assembling enriched uranium or plutonium into a supercritical mass and then by either by shooting one piece of sub-critical material into another, which is called the gun method, or by compressing using explosive lenses a sub-critical sphere of material using chemical explosives to many times its original density, which is known as the implosion method. The implosion method is used only with plutonium and does not work with uranium. For uranium, the gun method is more popular.