FIREWORKS LIGHT AND SOUND IN A PAPER TUBE

摘要

Invented in ninthcentury China, this mix of potassium nitrate, charcoal, and sulfur is what makes fireworks (plus guns and explosives), well, work. In a traditional firework a lit fuse kicks off the reaction, igniting the powder in the bottom of the shell. As the potassium nitrate burns, it lets off oxygen. The O_2 helps the charcoal and sulfur burn too, producing hot gases that hurl the firework into the sky. Seconds later, a delayed fuse reaches the center of the payload, igniting the main shell to unleash a spectacle of light and sound.