Fireworks and What Makes Them Go

Fireworks and What Makes Them Go

Sparks! Colors! Things that go BOOM! Chemistry doesn’t get much better than this. Ever notice how minutes drag on for hours when you’re waiting for a fireworks show to begin? Everyone’s thinking the same thing: The sky is dark enough the hot dogs are all eaten…come on when are they going to start? Then the first rockets streak into the sky…Ooh! Aah! Yes, it was worth the wait.

The birthplace of fireworks is generally recognized as China.

The first explosive mixture was black powder, during the Sung dynasty (960-1279). It is said that a cook in ancient China found a mixture of sulfur, potassium nitrate, and charcoal was very flammable and would explode if enclosed in a small space (History of Fireworks). The first application of this technology was for entertainment. The Chinese are still the leaders in the production of fireworks. Once the recipe for black powder was perfected, they found that it was easily used as rocket fuel, and they made hand carved wooden rockets in the shape of a dragon in the sixth century (History of Fire Works).

These rockets shot rocket powered arrows from their mouths, and were used against the Mongol invaders of 1279. The principle behind these rockets is still used in rocket powered fireworks today (History of Fireworks).

What goes on when fireworks go off? Well it’s all pyrotechnics, which are chemical substances that produce light and smoke when ignited. Pyrotechnics are also used in flares, smoke bombs, explosives, and matches. An aerial fire work is a rocket made of a cylinder, chemicals inside the cylinder, and fuses attached to the cylinder. The chemical mixture that makes up a firework is black gunpowder, which is potassium nitrate, sulfur, and charcoal. When ignited this mixture makes a small explosion. Also when these three chemicals react with one another they produce carbon monoxide, carbon dioxide, and sulfur dioxide (How Fireworks Work). These gases expand very rapidly lifting the rocket into the sky.

However black powder is not the only set of chemicals in the cylinder. The other chemicals provide the color bursts. There are two main color production mechanisms in fireworks.

Incandescence

Incandescence is light produced from heat. Heat causes a substance to become hot and glow, initially emitting infrared, then red, orange, yellow, and white light as it becomes increasingly hotter (Making Light). When the temperature of a firework is controlled the glow of components, such as charcoal, can be manipulated to be the desired color at the proper time. Some metals, such as aluminum, magnesium, and titanium, burn very brightly and are useful for increasing the temperature of the firework (Making Light).

Luminescence

Luminescence is light produced using energy sources other than heat. Sometimes luminescence is called cold light because it can occur at room temperature and lower temperatures. (Making Light) To produce luminescence, energy is absorbed by an electron of an atom or molecule, causing it to become excited,