Fireworks have been a part of our lives since some unknown person in China, around the year 200 BC, tossed green bamboo in a fire and noticed that it crackled and popped. The first modern fireworks appeared in China in the 9th century AD, when alchemists developed huo yao (the fire drug), which was the precursor to black powder. By the 1400s, fireworks had spread to Europe, where Italian artisans crafted the first true artistic fireworks.

Today’s fireworks are incredibly sophisticated, but they rely on the same basic chemistry as their historical counterparts. Here is what you should know about the chemistry of fireworks.

Chemical Composition

Each firework contains a fuel source that ignites and explodes. Modern gunpowder was first used in fireworks around 1781, and is largely unchanged today. It contains sulfur and charcoal, as well as saltpeter (potassium nitrate), which serves as an oxidizer—it provides the needed oxygen for combustion of the fuel.

Fireworks also contain a binder, which holds together all of its components. Most often, a starch such as dextrin is used, which will later become an additional fuel source. The binder may also contain additional oxidizers, such as chlorates or perchlorates, to provide oxygen for the combustion of the binder. The binder is dampened with water to a doughy consistency.

When a firework is lit, an initial lift charge drives the firework into the air, lights a fuse, and triggers its chemical reaction. At the top of its arc, the firework explodes, releasing its stars in a shower of special effects.

How Fireworks Colors Are Created

Fireworks are packed with stars, the size, shape, and packing of which determine the effect. To create colors, the stars are filled with metals or metal salts. The electrons of each metal or metal salt have their own unique gap between their ground state and their excited state. As the firework shell heats up, the energy sends the electrons into their excited state. After detonation, this energy is released as light. The wavelength depends on the size of the gap, and our eyes interpret different wavelengths as distinct colors.

Although every manufacturer has its trade secrets, chemistry tells us which metals or metal salts are typically used to create specific colors. Aluminum, beryllium, titanium, or magnesium may be used for white or silver fireworks. Lithium carbonate creates pale reds, while strontium carbonate creates vibrant reds. Sodium compounds are usually responsible for yellow fireworks, while bright golds usually contain lampblack, iron, or charcoal. Bright orange is typically calcium chloride, and intense blues are generally copper chloride. To create purple fireworks, manufacturers may mix strontium carbonate with copper chloride.

The next time you are enjoying a fireworks show, spare a thought for the brave chemists who first developed modern fireworks. Today we take them for granted, but at one time, these shows must have seemed mystical and more than a little dangerous.

At Dynamite Fireworks, we don’t only sell top-quality, name-brand fireworks. We also provide the information you need to know to use them responsibly, legally, and safely. If you have any questions or concerns, give us a call at (219) 937-4090. We look forward to becoming your one-stop shop for all your fireworks needs!