When we mention gunpowder, one of my country's "four great inventions", we often think of explosions and fireworks, but it is difficult to connect it with "medicine". However, as the name suggests, gunpowder should be "fire medicine" - its main characteristic is that it ignites when exposed to fire. So why is it called "fire medicine"? This starts with the composition of gunpowder and the history of the invention of gunpowder in our country.
The gunpowder invented in our country is now called black gunpowder. It is a mixture of three powders: saltpeter, sulfur, and charcoal in a certain proportion. The chemical composition of saltpeter is potassium nitrate, which is an oxidizing agent and releases oxygen when heated. Sulfur and carbon are easily oxidized and are common reducing agents. When the three are mixed together and burned, the oxidation-reduction reaction proceeds rapidly, releasing high heat and producing a large amount of gas. The volume expands rapidly and is prone to explosion.
Saltpeter and sulfur are commonly used medical drugs and alchemy drugs in ancient my country. my country's earliest medicinal classic "Shen Nong's Materia Medica", written as late as the Han Dynasty, lists saltpeter as a top-grade medicine and sulfur as a traditional Chinese medicine. It is said that sulfur "can transform gold, silver, copper and iron" and is a "wonderful thing". In order to change the properties of saltpeter and sulfur, the alchemists in ancient my country often used the fire-subduing method to refine them. The so-called fire-subduing method is to tame "violent" drugs by burning them to achieve the desired purpose. Alchemists discovered in a fire that mixing saltpeter, sulfur and charcoal was very easy to burn, so they named it "gunpowder". The invention of gunpowder comes from people's long-term practice of refining alchemy and medicine. Even after the invention of gunpowder, gunpowder itself was still introduced into medicine. For example, in Li Shizhen's "Compendium of Materia Medica" in the Ming Dynasty, gunpowder was used to "treat sores and tinea, kill insects, and avoid moisture and plague."
It was only in the late Tang Dynasty that gunpowder broke through the limitations of "medicine" and was used in military affairs. During the Fifth Dynasty, in addition to rockets and artillery, fireballs, fire caltrops and other firearms were also manufactured and used. The gunpowder arrow invented in my country during the Song and Yuan Dynasties used the reaction force generated by gunpowder injection to launch the arrow. It can be said to be the originator of modern rockets.