Why are fireworks burning brighter?
In the past, the colors were produced by igniting charcoal, starches and gums, while today these have been replaced by metal fuels, explains chemist John A. Conkling, Ph.D., of Chestertown, Md., former technical director of the American Pyrotechnics Association. "These metals produce hotter flames, which produce more photons of emitted light and a variety of more vivid colors," he said in a recent interview. For example, barium monochloride in a flame produces green; strontium monochloride produces red; and copper produces blue emission, according to Conkling.
Today, he adds, the colors are even brighter because of fine-tuning of the percentages of the ingredients used in the fireworks. Besides the fuel and oxidizer, a typical fireworks burning mixture consists of a compound containing one of the metals and a chlorine-giving compound, he explains.
The first fireworks had fewer ingredients, reports Chemical & Engineering News, the newsmagazine published by the American Chemical Society, the world's largest scientific society. To access a C&EN article tracing the beginning of this form of entertainment to the Far East go to http://www.cen-online.org and click on "What's That Stuff?" The site is a winner of a Scientific American Sci Tech Web Award for one of the best science Web sites for the public.
More than a thousand years ago, probably in China, someone discovered that a mixture of sulfur, charcoal and saltpeter (potassium nitrate) burned quickly and with a flash, the newsmagazine reports. The mixture, which later became known as gunpowder, was used in China for centuries to scare off evil spirits and, later, to f
Contact: Michael Bernstein
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