The chemistry behind a firework explosion

It's Independence Day, and that means it's time for controlled explosions in the sky. No, not Texas post-rock -- the great scientific display that is a fireworks show. "Fireworks are an application of chemistry and engineering: you need good chemistry to get the effects up in the sky and good engineering to make sure they get to the right altitude and burst at the right time," John Conkling, the former director of the American Pyrotechnics Association, tells The Verge. Firework shows last betwee...