Fuse (explosive)

An explosion is a powerful and rapid release of energy, often due to a fuse triggering a sudden violent chemical reaction.

Gunpowder, and other early explosives, relied on very rapid combustion, and so could be triggered by a spark of flame. Striking a piece of flint, a rock that sparks, when hit, could form the core of a fuse.

In the late 19th century chemists developed high explosives -- chemical compounds that could release violent chemical reactions, without being surrounded by oxygen for combustion.

Nitro-glycerine was a dangerous high-explosive, that had to be used with great care, as it could explode merely by being shaken.

Alfred Nobel, and his brother, manufactured nitro-glycerine, and after his brother died, in spite of precautions, he worked to develop a safer alternative to nitro-glycerine.

Once relatively stable high explosives were available fuses to trigger them were required. The "blasting cap" is one such fuse. These pencil shaped fuses contain a pinch of a relatively volatile high explosive, like mercury fulminate. That pinch of volatile high explosive detonates when energized by a small electric current. That explosion is strong enough to trigger an explosion in the safer high explosives.

Atomic bombs, that rely on the nuclear fission of unstable isotopes of Uranium, or other heavy elements, also require fuses. Uranium 235 and Plutonium 239 radiate neutrons. When a critical mass of radioactive heavy elements are brought together those neutrons strike other atoms, triggering them to release more neutrons. An explosion takes place when the release of neutrons is so intense there is a runaway chain reaction. The fuses for these fission bombs relied on high explosives to force fissionable elements together quickly.