Bigger, brighter and more colorful every year, fireworks cap off Independence Day celebrations around the country.
More than 1,000 years ago, most likely in China, someone made the serendipitous discovery that a mixture of sulfur, charcoal, and saltpeter (potassium nitrate) burned with startling speed and flash. The mixture, which eventually came to be known as gunpowder, was a Chinese mainstay for centuries, used in ceremonies to scare off evil spirits and even in military rockets.
Gunpowder made its way to Europe, probably during the early 1200s. During the Middle Ages, gunpowder-based creations–the precursor to modern fireworks–were limited to booms and a few sparkles, aided by a few iron filings or some copper or zinc. The repertoire of colors was that found in most campfires: oranges, yellows, and the occasional white-hot.
It wasn’t until the 1800s that chemists began to use then-recently synthesized compounds that, in the right mixtures, burned in reds, greens, even blues and purples, and that the colors we traditionally ascribe to fireworks began to show up in night skies.
But with the exception of minor formula improvements, your fireworks colors have been the fireworks colors of your great-grandparents–until recently. Connoisseurs of Fourth of July displays may have noticed that over the past two decades, colors have gotten markedly more vivid. Even blue, the most difficult color of all to produce, has evolved from an anemic bluish white to something approximating an honest-to-goodness blue.
Visit ”What’s that Stuff” to read more about fireworks.
Excerpted with permission, Chemical & Engineering News
Copyright © 2001 American Chemical Society