The History of Fireworks

Happy Fourth of July.

PyroUniverse.com reports:

The history of fireworks goes back thousands of years to China during the Han dynasty (~200 B.C.), even long before gunpowder was invented. It is believed that the first "firecrackers" were likely chunks of green bamboo, which someone may have thrown onto a fire when dry fuel ran short. The rods sizzled and blackened, and after a while, unexpectedly exploded. Bamboo grows so fast that pockets of air and sap get trapped inside of the plant's segments. When heated, the air inside of the hollow reeds expands, and eventually bursts through the side with a long bam!

The strange sound, which had never been heard before, frightened people and animals terribly. The Chinese figured that if it scared living creatures so much, it would probably scare away spirits
particularly an evil spirit called Nian, who they believed to eat crops and people. After that, it became customary for them to throw green bamboo onto a fire during the Lunar New Year in order to scare Nian and other spirits far way, thus ensuring happiness and prosperity to their people for the remainder of the year. Soon, the Chinese were using bursting bamboo for other special occasions, such as weddings, coronations, and births. The "bursting bamboo", or pao chuk as the Chinese called it, continued to be used for the next thousand or so years.

Discovery of Gunpowder

Though a precise date of origin is impossible to determine, most historians believe that the very first pyrotechnic composition - a precursor to gunpowder - was first discovered sometime during the Sui and Tang dynasties (~600-900 A.D.) in China. It was most likely discovered accidentally by alchemists who were experimenting with sulfurous mixtures in an attempt to create an elixir of life. During this period of chemical discovery and experimentation, the alchemists kept records of certain poisonous and dangerous compositions that should never be mixed - including one particular mixture consisting of sulfur, saltpeter (potassium nitrate), honey, and arsenic disulfide. The texts make reference to such a mixture igniting accidentally while being cooked over a fire, resulting in a large, bright, hot flame that burned the hands and faces of the alchemists tending to it, and even burnt down the shack there were cooking it in! Despite the warnings, some alchemists were intrigued by the mixture, and continued experimenting with it to try to find ways to make it more powerful. Their crude mixtures weren't as powerful as modern gunpowder because it didn't contain as much potassium nitrate, but nevertheless burned very hot and bright. It was named huo yao, or the "fire chemical" or "fire drug". It was soon discovered out that if the "fire drug" was put inside of bamboo tubes and thrown in the fire to be ignited, the gases produced by the burning powder would blast the tube apart with a much louder and more powerful bang than just green bamboo. The firecracker was born.

Over time, chemists discovered that the key to the vigorous burning of gunpowder was the fact that saltpeter was rich in oxygen, which it released as it burned. They soon figured out how adding more saltpeter to the mixture made it burn faster, thus making it a more powerful explosive and louder when used in firecrackers. Charcoal - the by-product of the incomplete combustion of cellulose-based plant matter, such as wood - was replaced honey and other materials in the early formulas. Through much experimentation, it was discovered that gunpowder-based devices could function in many different ways, depending on their construction. As previously mentioned, when gunpowder was ignited in a confined space, such as a bamboo tube, log, or iron shell, it would generate hot gases under enormous pressure that would eventually rupture the container, creating a load report and sending pieces of the container flying in all directions. If placed in a container with an open end, the burning powder would create a brilliant eruption of flame, sparks, and dense smoke out of the end of the container. The Chinese were well aware of the killing power of these explosive devices, and by the 10th century, began using them for military purposes. The Chinese used their gunpowder to create a variety of explosives, including crude bombs and "fire arrows" - bamboo firecrackers attached to regular arrows and shot at the enemy. The initial intent behind the early Chinese bombs was simply to practice psychological warfare - the terrifying, earth-rattling, lightning-like explosions had never been created by any man-made device, and they could easily frighten and confuse enemies, forcing them to flee.

Eventually, however, the aim shifted from scaring the enemy to actually inflicting harm. Fire arrows could be rained down upon the enemy from a great distance, and bombs could be dropped from the walls of fortresses onto enemy troops. Another weapon, known as the fire lance, consisted of an open tube filled with gunpowder attached to a lance, which could be used as a crude flamethrower. Bits of rock, metal, pottery and even arrows could also be mixed with the powder inside of the fire lance, which would be spewed out as it burned, inflicting additional damage. Around the 11th century, the proportion of saltpeter in gunpowder was raised to about 75% of the total mixture, along with about 15% charcoal and 10% sulfur (that same formula is still used today, nearly 1000 years later!).

As the gunpowder became more energetic, firecrackers began to change. Rather than using bulky bamboo stems, firecracker makers began filling stiff paper tubes with gunpowder and inserting fuses made from tissue paper with a trail of gunpowder inside. A variation of a firecracker, called a "ground rat", was first believed to have been discovered around 1200 A.D. It consisted of a lightweight paper firecracker that was open on one end. Like the fire lance, the burning gas inside shot out of the opening and propelled the "rat" randomly around the ground. Rats were quickly adapted for use by the Chinese military because of their psychological effect on the enemy - scaring soldiers and causing horses to go wild. Often, the unpredictable movement of the rats would fly into the air momentarily, which gave the military designers the idea of putting guidance fins on the rats to straighten their flight path. This led to the creation of the first rockets. Civilian firework makers took the military's rocket design and modified it to include an explosive charge, which were then fired into the air - marking the first use of aerial fireworks.

Warfare

Through use of the fire lance, it was discovered that the more solid objects (such as arrows or stones) that were packed in with the gunpowder of a lance, the more force they were shot out with. If the arrows and other objects were replaced with a single large projectile only lightly smaller than the diameter of the tube, the burning powder would eject the object at a considerable speed and propel it a substantial distance - the cannon was born. The first cannons made by the Chinese were constructed from bamboo tubes! However, bamboo was often too weak to contain an explosion, so crude cannons began to be fashioned out of metal tubes. The military use of gunpowder slowly began to spread across Asia and into the Middle East, and during the 1200s, cannons and rockets were used extensively in the Mongol Conquests in Asia.

During the same time period - about the middle of the 13th century - the news of gunpowder traveled across the world to Europe via Dominican and Franciscan friars. One of these friars actually brought back some Chinese firecrackers and gave them to Roger Bacon, a Franciscan monk and lecturer at Oxford University in England. Bacon became one of the first Europeans to study gunpowder and write about it. He knew that saltpeter was the driving force behind the terrifying noise of firecrackers, and discovered a way of purifying the natural mineral out of the earth to make more powerful gunpowder. He realized the potential of this substance to revolutionize warfare and cause many deaths, so he wrote in findings code.

Eventually, however, efforts by other scientists to improve gun powder (as well as the decoding of Bacon's formulas) led to a warfare revolution in Europe. People created bigger, stronger, more powerful cannons that were capable of propelling large iron balls to far-off targets. It was then that traditional, centuries-old medieval warfare came to an end - because of gunpowder, metal armor could be punctured by bullets, and the once seemingly-impenetrable walls of castles could easily be disintegrated by cannon balls. Soon after, cannon balls were made hollow so that they could be filled with gunpowder and a fuse. If aimed correctly, these flying bombs would explode right before or near the time of impact with the target, which proved very effective in blasting apart walls and showering the enemy with metal shards (shrapnel).

In order to compete with and defeat other armies, it became essential that each and every kingdom in Europe be equipped with artillery divisions. To supply the amount of gunpowder needed by these armies, factories known as "powderworks" were built in order to grind and mix gunpowder. These facilities typically used the power of mules or running water to turn heavy circular stones in order to crush the power and achieve a homogenous mixture. Not surprisingly, these places would occasionally explode due to a friction-generated spark on the grinding wheel, which often resulted in many fatalities. Armies would often celebrate each victory with thundering booms and bright flashes from their weapons. Rather than being aimed for ground targets, cannons and rockets were pointed towards the sky to make aerial bursts.

During 1400-1600, advances in metallurgy allowed for the creation of more advanced cannons, as well smaller gunpowder weapons such as muskets. Though the weapons were inaccurate, unreliable, and no where near as powerful as modern firearms, they were much more advanced than bows, arrows and catapults. Firearms technology in Europe eventually surpassed that of China.

Development of Fireworks

Meanwhile, the Italians had been fascinated with fireworks ever since the explorer Marco Polo brought back firecrackers from the Orient in 1292. During the Renaissance in Europe (1400-1500), the Italians began to develop fireworks into a true art form. Since this was a period of artistic creativity and expression, many new fireworks were created for the first time. Military rockets could be modified by adding powered metals and charcoal in order to create bursts of gold and silver sparks in the sky. The Italians were able to develop aerial shells - canisters of of explosive composition that were launched into the sky and exploded at the maximum altitude (the Chinese also developed shells that were spherical in shape). However, the most spectacular firework displays were still those made at ground level. Firework makers discovered how a special slower-burning gunpowder mix could be put in an open-ended tube, which would give off sparks when lit. The dense showers of bright sparks resembled water spewing from a fountain, so the new pyrotechnic device was named accordingly. If rocket engines were attached to a wooden wheel framework, it would spin around rapidly and give off sparks in a circular pattern. Sculptors would carve giant, detailed models of castles or palaces, which would be adorned with fountains, wheels, and torches. These "temples", as they were called, were a beautiful and crowd-pleasing sight when ignited. Such displays became in high demand throughout Europe. The idea of controlled fire was fascinating to all, and kings saw no better way to show their wealth and power then by having fireworks at their religious festivals, weddings, and coronation ceremonies.

These firework displays grew more and more elaborate over the years, employing the work of carpenters, metalworkers, masons, and painters to help construct the temples. Firemasters learned that the effects of fireworks could be greatly enhanced by setting them on small floats in water, where more light and noise would be reflected back towards the audience. Starting in the early 1530s, fireworks would usually be ignited by "green men", a term given to firemasters who covered their faces in soot and dressed in leaves in order to both protect themselves from sparks and be hard to see as they ran around lighting fuses. From 1500-1700, the most popular type of firework was the "dragon". The massive device consisted of a wooden framework which was covered in painted paper-maché scales. Inside, it was loaded with fountains, firecrackers, and rockets, some of which would shoot out of the mouth to make it "breathe fire". Often times, two or more dragons would be constructed and aimed at each other as they ignited to "battle".

Around the 1730s, firework shows in England became huge public displays rather than just the private entertainment of royalty. People from all over Europe would come to witness the spectacular fireworks displays at amusement parks in Britain. The discovery of "quick match" - a fast-burning fuse made by putting regular fuse into a small, continuous paper tube - gave firemasters the ability to ignite many fireworks simultaneously, and enabled the construction of set pieces. Set pieces are giant pictures/words made from hundreds of small burning torches, which were often created in the likeness of popular figures such as royalty.

Fireworks in the New World

Settlers brought fireworks over to the Americas around the 1600s, where they continued to be used to celebrate special occasions and to impress or scare off Native Americans. The very first 4th of July celebration was in 1777, only one year after the signing of the Declaration of Independence. The United States was still in the midst of the Revolutionary War and the outcome was still uncertain, but beautiful displays of fireworks instilled a sense of hope and patriotism in the citizens of the young nation. When trade relations were established between the U.S. and China less than a century later, Chinese firecrackers became a major import in America.

For nearly 1000 years, the only colors that could be produced by fireworks was the orange flash/sparks from black powder, and white sparks from metal powders. But in southern Italy in the 1830s, scientific advancements in the field of chemistry enabled pyrotechnicians (the modern term for the old "fire masters") to create reds, greens, blues, and yellows by adding both a metallic salt (strontium=red, barium=green, copper=blue, sodium=yellow) and a chlorinated powder to the firework composition. Potassium chlorate (KClO3), a new oxidizer that burned faster and hotter than potassium nitrate, allowed pyrotechnicians to make the new colors deeper and brighter. The harnessing of electrical energy made it possible to obtain pure magnesium and aluminum by electrolysis, which also made fireworks burn brighter. When fine aluminum powder was mixed proportionally with an oxidizer, the resulting mixture - flash powder - burned much hotter and faster than black powder, allowing for the manufacture of louder firecrackers and salutes in aerial fireworks.