The Amazing Advancements in Firework Technology
With the Fourth of July holiday sure to add a spark of color to the evening skies this weekend, many might be wondering how those dazzling displays have evolved.
Why We Celebrate With Fireworks
Fireworks first lit up American skies above Philadelphia and Boston in the midst of the Revolutionary War, during our fledgling nation’s first Independence Day celebration in 1777. They’ve since become the centerpiece of all Fourth of July festivities, justifying John Adams’ claim in 1773 that fireworks will grace the new country with “...Illuminations from one End of this Continent to the other from this Time forward forever more.”
But the earliest fireworks were born more than 2,000 years ago in China. These ancient firecrackers required very little mechanical engineering, only the chopping of bamboo. Two millennia ago, the inhabitants of Liuyang tossed those bamboo stalks onto fires and marveled at the resultant crack, caused by air pockets expanding and popping. It was said to dispel evil spirits.
Some 500 years later, Chinese alchemists accidentally invented black powder while concocting an elixir for immortality. Stuffing that powder into bamboo stalks, they created the first chemical fireworks.
The Recipe Hasn’t Changed Too Much
More than a millennia later, modern fireworks still rely on that black powder for their bang. Only nowadays that black powder (a mix of potassium nitrate, sulfur and charcoal) is sprinkled with a formulation of metal compounds. When metals are heated they emit light at different wavelengths, producing the brilliant colors that give fireworks their beauty. For example, copper burns blue, barium green, strontium red and sodium yellow. A dash of magnesium or aluminum adds sparkle and an intense white or silver brilliance.
Technicians portion the mix into pellets called “stars.” Stars are packed into paper shells in various configurations to produce different designs when they burst. Each shell is equipped with a fuse and loaded into a mortar, along with varying amounts of black powder to pop it higher or lower into the air. The mortars are activated electronically, either by human operators or a computer program, ensuring that the shells reach the specified altitude in the correct order and burst at the right time. No wonder a good show can cost thousands of dollars per minute.
Automation Leads To More Sophisticated, Safer Displays
Modern firework automation allows for elaborate aerial displays and improved safety, but also the rare hiccup. That rare (but spectacular) hiccup occurred on the Fourth of July in 2012, in San Diego. The “Big Bay Boom” event promised a 17-minute fireworks extravaganza over San Diego Bay. But a computer glitch launched all 7,000 shells in a 30-second flurry:
The Future Of Fireworks
Future advances in pyrotechnics are leading to the development of less-polluting products. Firework displays pump plumes of soot into the air and deposit toxic perchlorates (chemicals added to boost combustion) into water supplies. But these advances are, surprisingly, led by Hollywood and the military, not the commercial industry.
The entertainment industry uses pyrotechnics during filming and to enhance live performances, where a cleaner-combusting product is desired to eliminate the noxious smoke and stench. The military relies on pyrotechnics to simulate combat scenarios, and is developing cheaper, more eco-friendly alternatives to limit chemical contamination on training sites.
In the commercial sector, New York-based Fireworks by Grucci is developing fireworks that disperse less ash, smoke and powder. These cleaner-burning variants can deploy from hotel rooftops and at national monuments or parks. And “pixel-burst” technologies allow for more precise, computer-mediated control of where and when fireworks detonate. Operators can create images in the sky by placing each explosion like a pixel.
As we prepare to celebrate the Fourth of July, it’s a perfect time to reflect on scientific progress. From the first bamboo stalk firecrackers to the evolution of a billion-dollar industry, fireworks exemplify engineering at its finest.