Fireworks captivate us with a vibrant display of light and colors. Behind these lies a complex series of chemical reactions, from the initial ignition to the final burst of colors. Let’s explore the chemistry of fireworks.
Oxidizers
- A chemical rich in oxygen (nitrates, chlorates, or perchlorates)
- Provides the oxygen necessary for the mixture to burn.
- The oxidizing agent will receive the electrons and cause the release of energy.
Fuel (Gunpowder)
- Usually composed of charcoal and sulfur.
- Gunpowder was originally discovered by Chinese alchemists
- It was made with a combination of honey, sulfur, and saltpeter (potassium nitrate). Charcoal replaced honey.
- In modern times, gunpowder has a weight ratio of 75:15:10 saltpeter:charcoal:sulfur, which hasn’t changed since 1781!
Here’s the chemical reaction of gunpowder:
\[6KNO_3 + C_7H_4O + 2S \to K_2CO_3 + K_2SO_4 + K_2S + 4CO_2 + 2CO + 2H_2O + 3N_2 \]
Colorant
- Metals burn in different colors due to the electron arrangements in the outer shell of the metal’s nucleus, and the emission of different wavelengths of light.
Binder
- Usually made of dextrin
- Brings together all the components
- Serves as the fuel after ignition
- Makes sure fireworks don’t unexpectedly explode
- Serves as the source of electrons that will be burned later.
