Gunpowder Facts, History and Description

Gunpowder Facts, History and Description Gunpowder or black powder is of great historical importance in chemistry. Although it can explode, its principal use is as a propellant. Gunpowder was invented by Chinese alchemists in the 9th century. Originally, it was made by mixing elemental sulfur, charcoal, and saltpeter (potassium nitrate). The charcoal traditionally came from the willow tree, but grapevine, hazel, elder, laurel, and pine cones have all been used. Charcoal is not the only fuel that can be used. Sugar is used instead in many pyrotechnic applications. When the ingredients were carefully ground together, the end result was a powder that was called serpentine. The ingredients tended to require remixing prior to use, so making gunpowder was very dangerous. People who made gunpowder would sometimes add water, wine, or another liquid to reduce this hazard since a single spark could result in a smoky fire. Once the serpentine was mixed with a liquid, it could be pushed through a screen to make small pellets, which were then allowed to dry. How Gunpowder Works To summarize, black powder consists of a fuel (charcoal or sugar) and an oxidizer (saltpeter or niter), and sulfur, to allow for a stable reaction. The carbon from the charcoal plus oxygen forms carbon dioxide and energy. The reaction would be slow, like a wood fire, except for the oxidizing agent. Carbon in a fire must draw oxygen from the air. Saltpeter provides extra oxygen. Potassium nitrate, sulfur, and carbon react together to form nitrogen and carbon dioxide gases and potassium sulfide. The expanding gases, nitrogen and carbon dioxide, provide the propelling action. Gunpowder tends to produce a lot of smoke, which can impair vision on a battlefield or reduce the visibility of fireworks. Changing the ratio of the ingredients affects the rate at which the gunpowder burns and the amount of smoke that is produced. Difference Between Gunpowder and Black Powder While black powder and traditional gunpowder may both be used in firearms, the term black powder was introduced in the late 19th century in the United States to distinguish newer formulations from traditional gunpowder. Black powder produces less smoke than the original gunpowder formula. Its worth noting early black powder was actually off-white or tan in color, not black! Charcoal Versus Carbon in Gunpowder Pure amorphous carbon is not used in black powder. Charcoal, while it contains carbon, also contains cellulose from incomplete combustion of wood. This gives charcoal a relatively low ignition temperature. Black powder made from pure carbon would barely burn. Gunpowder Composition There is no single recipe for gunpowder. This is because varying the ratio of the ingredients produces different effects. Powder used in firearms needs to burn at a fast rate to quickly accelerate a projectile. A formulation used as a rocket propellant, on the other hand, needs to burn more slowly because it accelerates a body over a long period of time. Cannon, like rockets, use a powder with a slower burn rate. In 1879, the French prepared gunpowder using 75% saltpeter, 12.5% sulfur, and 12.5% charcoal. The same year, the English used gunpowder made from 75% saltpeter, 15% charcoal, and 10% sulfur. One rocket formula consisted of 62.4% saltpeter, 23.2% charcoal, and 14.4% sulfur. Gunpowder Invention Historians believe gunpowder originated in China. Originally, it was used as an incendiary. Later, it found use as a propellant and explosive. It remains unclear when, exactly, gunpowder made its way to Europe. Basically, this is because records describing the use of gunpowder are difficult to interpret. A weapon that produced smoke might have used gunpowder or could have used some other formulation. The formulas that came into use in Europe closely matched those used in China, suggesting the technology was introduced after it had already been developed. Sources Agrawal, Jai Prakash (2010). High Energy Materials: Propellants, Explosives and Pyrotechnics. Wiley-VCH.Andrade, Tonio (2016). The Gunpowder Age: China, Military Innovation, and the Rise of the West in World History. Princeton University Press. ISBN 978-0-691-13597-7.Ashford, Bob (2016). A New Interpretation of the Historical Data on the Gunpowder Industry in Devon and Cornwall.  J. Trevithick Soc.  43: 65–73.Partington, J.R. (1999). A History of Greek Fire and Gunpowder. Baltimore: Johns Hopkins University Press. ISBN 978-0-8018-5954-0.Urbanski, Tadeusz (1967),  Chemistry and Technology of Explosives,  III. New York: Pergamon Press.