I dont understand why country's make weapons of mass destruction, when they can eventually result to the end of the world if a nuclear war was to happen.
Nuclear weapon designs are phisical, chemical, and engineering placements which follow up to the detonation of the weapon. Nuclear weapons are often divided into two classes, fission and fusion bombs.
Fission bombs get their power from nuclear fission, where heavy uranium or plutonium in the nuclei which is hit by neutrons and split into lighter elements. A nuclear chain reaction occurs which releases large amounts of energy. These are called atomic bombs from the fact that chemical reactions release energy from atomic bonds.
Fusion bombs are based on nuclear fusion where light nuclei such as deuteriom and tritium join together into heavier elements and release large amounts of energy. Fusion requires extremely high temperatures to occur.
These two types of weapon is blurred by the fact that they are combined in other complex modern weapons. Other specific types of bombs are the neutron bomb and cobalt bomb.
The simplest technique for assembling a nuclear weapon is to shoot one piece of fissile material as a projectile against a second part as a target, usually uranium. This is called the Gun method
Perfect example of a Gun method detonation.
Some more complex weapons are made by detonation of an implosion method. Basically an implosion device creates smaller explosivies surrounding the material to rapidly compress the mass to detonate the main bomb.
Perfect example of an implosion detonation.
Staged thermonuclear weapons, or hydrogen bombs, use the power of a fission bomb to ingnite fusion fuel. This is in a staged process in that they chain together different weapon components for large explosion.
This is an example of the staged process of hydrogen bombs.
These pictures are found on this site and to learn more about weapons design go to <http://en.wikipedia.org/wiki/Nuclear_weapon_design>