Fireworks 101

Nothing says, “Happy Independence Day!” like the crackle and bang of a pyrotechnics display. Dazzle your barbecue guests with this fireworks trivia

• Fireworks first appeared around 1000 A.D., in Chinese religious ceremonies.
• Various metal salts are used to create the colored explosions. Barium makes green, copper makes blue, and aluminum is responsible for the sparkle.
• Smiley faces, words, and logos. Fireworks have expanded far beyond the classic palm tree. To make different shapes, a chemical mixture is glued to wax paper in the form that it will take when it explodes. Next, the paper is put inside a spherical shell made of cardboard or some other paper. Several are fired off at the same time to give the appearance of three dimensions, says John Steinberg, a vice president of the Pyrotechnics Guild International.
• The United States imported around $217 million worth of fireworks in 2007, with $207 million of that coming from China, according to the U.S. Census Bureau.