Have you ever wondered what is behind those exciting, gorgeous fireworks that you look forward to every year? Well, there's a lot more than you might think!
The colors, or "stars," in fireworks depend upon a wide variety of metal compounds – specifically metal salts. (No, not table salt; a "salt" is actually any compound that contains metal and non-metal atoms bonded together – though table salt, NaCl, is definitely an example!!)
Different salts produce different colors. Here's a list below of some of the different salts and their corresponding colors:
- Red – strontium salts
- Orange – calcium salts
- Yellow – sodium salts
- Green – barium salts
- Blue – copper salts
- Purple – combine copper and strontium compounds
- Silver – white hot magnesium and aluminium
- White – burning metal
Some colors are more difficult to produce than others based on the properties of the particular metal salt. For example, copper, which exhibits a blue coloration, is not stable at high temperatures; so blue color is not emitted at high temperatures. Purple is also difficult, as it is a combination of blue and red – resulting in the same problems as the blue fireworks. So, if your firework show has blue fireworks, you're watching a high quality display!
Fireworks also have other materials in them besides the salts for coloration. The most important component to the fireworks is the gunpowder, also deemed "black powder." The combustion of the black powder is not one single reaction, but actually a series of reactions. In addition to this, fireworks contain a "binder," which is used to hold all of the components together and dictate the level of impact the firework has.
Now that you know a little bit about the chemistry behind fireworks, you can appreciate them with a whole new perspective! Happy Independence Day!
