Illuminating Facts About Fireworks

1 THE FIREWORKS that you'll see this Fourth of July were most likely made where else?-in China.

- Samantha Rideout

The country that makes 90% of the world's fireworks is also where they were invented. Most historians believe that the Chinese used firecrackers as early as the second century B.C.

2 AMERICANS AREN'T the only ones setting off sparklers this month. Canadians put on pyrotechnic displays every July 1 to celebrate their own national birthday, as the French do on July 14 to mark the anniversary of their revolution. But the U.S. imports most of the world's fireworks, spending more than $650 million on them per year. The Walt Disney Co. alone buys about $50 million worth.

3 A MIXTURE Of gunpowder and other flammable compounds causes fireworks to explode across the sky in all those pretty colors and fun shapes. Copper, for instance, burns bright blue; strontium sparks deep red. Together, they produce purple. But the outlines fireworks form depend on the placement of these compounds inside their casing (known as the shell), as well as the shape of the shell itself. Crowd favorites include "comet," which features a long trail of sparks; "peony," a spherical burst; and "strobe," which produces a blinking effect.

4 ITALIANS WERE the first to mix in extra metals to create different colors, in the 1830s. Before that, not surprisingly, all fireworks were orange, the most common color of fire. The patterns are a result of much more recent technology. The first patch of sky to see specific shapes was the one above Washington, D.C.: We welcomed our troops home from Operation Desert Storm in 1991 with fireworks that exploded into purple hearts and yellow bows.