It has been more than a thousand years since our ancestors invented gunpowder. Gunpowder, which was invented at that time, is now called black powder; Because of its brown color, some people call it brown gunpowder. It is a mixture of nitric acid, sulfur, and charcoal. This mixture is extremely easy and quite intense to come up with. This is because nitric acid is an oxidizing agent that releases oxygen when heated. Sulfur and carbon are susceptible to oxidation and are common reducing agents. When they are mixed, the redox reaction proceeds rapidly, with high heat and a large amount of gas being released. If the mixture is wrapped in paper, cloth, skin, or stuffed in a clay pot or stone hole, and the volume suddenly expands to several thousand times, it will explode. This is how the explosion of black powder works.

As the name suggests, gunpowder is "the powder that catches fire". Ignition on fire is its main characteristic. So why is it called "medicine"?

In the late Spring and Autumn Period (the sixth century B.C.), there was a person named Ji Ran who said: "Shiliu Huang out of Hanzhong" and "Stone out of Longdao". Stone flow yellow is sulfur yellow; Eliminated stone is saltpeter, in ancient times also called flame nitrate, fire nitrate, bitter nitrate, frost and so on. It can be seen that as early as the Spring and Autumn Period and the Warring States Period, charcoal, sulfur, and saltpeter have been well known to people. In China's first medicinal material classic, the Han Dynasty's "Shennong's Materia Medica". Saltpeter and sulfur are both listed as important medicinal materials. Even after the invention of gunpowder, gunpowder itself was still introduced as a medicine. In the "Compendium of Materia Medica" written by Li Shizhen, a famous medical scientist in the Ming Dynasty, it is said that gunpowder can cure sores and ringworm, kill insects, and dispel dampness and plague. What's more, the invention of gunpowder came from people's long-term practice of alchemy and medicine. This is how the name of gunpowder was obtained.

Like other inventions, the invention of gunpowder has also undergone a long process of practice and understanding, and has been gradually perfected with the development of production and the progress of society.

First of all, there is a certain understanding of the properties of the three components that make up gunpowder. As early as the Shang and Zhou dynasties, charcoal was widely used in metallurgy. In practice, it has been learned that charcoal is a better fuel than firewood. Sulfur is naturally occurring and people have mined it for a long time. At the same time, in the smelting, the pungent sulfur dioxide escaping and the sulfur gas overflowing from the hot springs directly stimulate people's sensual palaces. It was during these exposures that some of the properties of sulfur were gradually recognized. In addition to the fact that it is known to have special curative effects on certain skin diseases, it also has certain peculiar properties. As said in "Shennong's Materia Medica": "Stone sulfur yellow...... It can turn gold, silver, copper, iron, and strange things. "That is, sulfur can be combined with metals such as copper and iron. In the "Zhou Yi Shen Tong Deed", the earliest alchemy book in China, the Eastern Han Dynasty, recorded the reaction of sulfur and mercury to form red mercury sulfide. These properties of sulfur are highly valued in the eyes of alchemists. Sulfur can not only combine with metals such as copper and iron, but also subdue the magic of mercury. Therefore, the monks often used sulfur in their vain attempts to refine the so-called "gold liquid" and "return the pill" with mercury. In experiments, it was also found that sulfur is easy to fly when ignited, and it is very difficult to catch it. How can we make it easier to control when it is mild? The monks used a method called the "fire method", which was mixed with certain flammable substances and heated or denatured to some extent. The invention of gunpowder is closely related to the experiments of this type of sulfur fire. The introduction of nitrate is the key to the production of gunpowder. The chemical properties of nitrate are reactive. Sprinkled on red charcoal, fireworks are immediately generated, which can interact with many substances, so in alchemy, nitrate is often used to change the properties of other medicines. At the same time, there are many ways to ambush fire saltpeter. And because the color of saltpeter is not much different from some other salts such as sodium sulfate, it is easy to make mistakes in use, so people have also mastered the method of identifying saltpeter. Tao Hongjing, a pharmacist in the Northern and Southern Dynasties, pointed out in the "Commentary on the Materia Medica": "If you burn it with fire, the purple and green smoke rises, and the cloud is saltpeter." "This is similar to the modern use of flame color reaction to identify saltpeter. This made the technical preparation for the later mass use of saltpeter.

The understanding of the properties of carbon, sulfur, and nitrate prepared the conditions for the invention of gunpowder. In the rising stage of China's feudal society, due to the development of medicine and alchemy activities, especially through long-term practice, at the latest in the Tang Dynasty, people observed in many experiments of volcanic sulfur and volcanic saltpeter that the mixture of ignited saltpeter, sulfur and charcoal would occur extremely intensely. In the fifth volume of the "Zhujia Shen Pin Dan Law", there is a "Sun Zhenren Dan Jing Inner Sulfur Method": take two taels of sulfur and saltpeter, grind them into powder, and put them in a silver pot or clay pot. Dig a pit and put pots in the pit and on the ground, and fill it with earth on all sides. The three soaphorns that have not been eaten by insects are lit one by one, and then they are put in a pot and the sulfur and saltpeter are burned to make fireworks. When the fireworks can't be burned, fry the charcoal again, fry until the charcoal is gone, then anneal, and before it has cooled, take out the mixture, and this will ambush the fire. From this account, it can be seen that at that time, it was understood that the ignition of a mixture of nitrate, sulfur, and carbon would react violently, and measures were taken to control the reaction speed and prevent explosions.

Similar experiments also appear in the second volume of the "Lead-Amalgam Heptane Zhibao Collection" in the middle of the Tang Dynasty. There was a man named Qing Xuzi, who said when talking about the "Fuhuo Alum Method": "Two taels of sulfur, two taels of nitrate, and three and a half coins of aristolochia." The right is the end, mix well. Dig a pit, and the human medicine is in the tank and the ground level. Put a piece of cooked fire, the marble is big, put it inside, the smoke gradually rises, cover it with four or five layers of wet paper, use a square brick piece to pound the mound, wait for the cold to take it out, and its sulfur is subdued. "In this experiment, the wild plant Aristolochia, like the soaphorn in the above experiment, works instead of charcoal. Care is also taken to prevent the mixture from becoming intense. Such an operation method is a summary of experience after repeated practice. Lessons about failure are also documented. Written around the time of the Five Dynasties (10th century AD), an alchemy book called "Zhenyuan Miaodao Yaolu" warned that if you combine sulfur, saltpeter, realgar (As2S2) and honey and burn them together, fireworks will occur, burning people's faces and hands, and they can also blindly rush to the house and burn the house. It can be seen that people are already familiar with the explosive properties of such mixtures, and they prevent them in alchemy. People consciously took advantage of this property of such mixtures, and gunpowder was mastered.

How much use is gunpowder exactly? What is the value of this invention? People at the time didn't understand it right away.

Before the invention of gunpowder, ancient military experts often used the tactic of fire attack to defeat the enemy. In the fire attack at that time, there was a weapon called rocket, which attached flammable substances such as grease, rosin, and sulfur to the arrow, ignited and shot out, and burned the enemy's ordnance personnel and barracks. But this rocket is slow, has little firepower, and is easy to extinguish. If gunpowder is used instead of ordinary flammable materials, it is faster and the firepower is also larger. Therefore, at the beginning of the Tang Dynasty, people had already adopted gunpowder arrows. This was the first form in which gunpowder was applied to weapons. Subsequently, on the basis of stone artillery, artillery was created. Artillery is a type of gunpowder that can be easily fired, and after the fuse is ignited, it is fired by the stone thrower. The use of gunpowder in weapons was a major advance in the history of weapons. In the war, gunpowder weapons showed unprecedented ability, which made it quickly attract people's attention, and many kinds of gunpowder weapons appeared one after another. In the third year of Zhu Zhenzong's Xianping reign (1000 AD), there was a captain named Tang Fu who dedicated his rockets, fireballs, and thistles to the Song court. In the fifth year of Chengping (1002 AD), the Jizhou regiment trained Shi Pu to make fireballs and fire tendons, and Song Zhenzong summoned him and let him perform in public.