- When Alfred Nobel invented dynamite in 1867, the invention made him rich beyond his wildest dreams--rich enough to fund the Nobel Prizes which are still awarded for scientific and cultural achievements today. Dynamite was such a success because it was the first explosive stronger than black powder (gunpowder) that could be safely handled. It revolutionized the construction and mining industries, as well as becoming a military weapon.
- Nobel, however, didn't actually invent a new explosive at all. The explosive in dynamite is simple nitroglycerin. Nitroglycerin is a very powerful explosive but, just as it's portrayed in the movies, "nitro" is very unstable and extremely dangerous to work with. A sudden shock can indeed set it off with deadly results. Nobel's innovation was to make nitroglycerin much safer to handle.
- He did it by soaking the liquid nitroglycerin into diatomaceous earth. Diatomaceous earth is a soft, chalky stone made up mainly of the shells of diatoms, tiny algae that live in a crystalline shell. The diatoms lived and died in ancient seas. Over millions of years their shells accumulated on the sea floor and were compressed into a soft stone that today is mined and used for filters and other uses. One of these uses is to absorb liquids. For example, diatomaceous earth is often used in making cat litter. Nobel found that it would absorb nitroglycerin as well. The resulting substance would still explode, but it was much harder to set it off. After Nobel's discovery, a number of dynamite variants were created using different materials to hold the nitroglycerin, such as sawdust or cellulose.
- Formed into explosive sticks of various sizes for particular purposes, dynamite is much safer to handle than nitroglycerin. (Of course caution is always called for when handling explosives and they should never be handled by anyone without proper training.) Dynamite is set off by the shock of a smaller explosion. This typically comes from a blasting cap, a small explosive charge that's inserted into the stick. When the blasting cap explodes, the shock is enough to then set off the dynamite.
- Dynamite is otherwise fairly difficult to set off. It does not ignite and explode in fire for example. While movies often show a burning fuse attached to dynamite, the fuse is to set off the blasting cap, not the dynamite itself. Without a blasting cap, dynamite can actually be burned. In fact, bomb disposal squads often burn old dynamite in place rather than risk moving it.
- Old dynamite is dangerous because, over time, the nitroglycerin starts to "sweat" out of the material its been absorbed into. This can result in a pool of liquid at the bottom of the box or a crystalline coating on the stick. In either case, this is raw nitroglycerin which can easily explode, possibly with enough force to set off the dynamite. More modern dynamite formulations are designed to resist this effect.
