Fireworks science saw an exciting combination of colors and sparks

Last time you watched a fireworks display, you probably saw an exciting combination of colors and sparks. Did you wonder just how this amazing pyrotechnics display worked? There’s a lot of chemistry involved in creating good fireworks!

One of the key ingredients for firecrackers, ground fireworks, and aerial fireworks (ones which explode in the sky) is black powder. It was invented by the Chinese about 1000 years ago. It’s a blend of potassium nitrate (saltpeter), charcoal, and sulfur in a 75:15:10 ratio. Black powder is used to launch aerials and also causes the explosions necessary for special effects like noise or colored light.

In sparklers, black powder is mixed with metal powders and other chemical compounds in a form that will burn slowly, top to bottom. In simple firework rockets, black powder is confined in a tube around a fuse. When lit, the powder creates a force that results in an equal and opposite reaction. This pushes the firework off the ground and causes the compounds inside it to explode in the air. More complex fireworks shells are launched from a mortar, a tube with black powder that causes a lift-off reaction when lit. The firework shell’s fuse is then lit as it goes up into the air, and at the right time an explosion inside the shell causes its special effects charges to burst.