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The Science Behind Fireworks

Updated: Dec 14, 2021

Aurora, IL

The Science Behind Fireworks, fireworks, sparklers, science, gunpowder, sulfur, stem, stars, shells, explosion, burst, light, show
A spectacular firework display over a city

Fireworks are an amazing addition to any party. They light up the sky and can be an awe-inspiring view for all ages. Fireworks are most commonly used on July 4th, when Americans celebrate Independence Day but can also be used to commemorate other festivities.

Fireworks have a unique scientific mechanism that allows them to produce the burst of light we all know and love. Fireworks are a combination of two types of pyrotechnic devices: sparklers and firecrackers. Sparklers consist of a fuel, an oxidizer, iron or steel powder, and a binder. The fuel is usually charcoal and/or sulfur. In order for combustion to occur, an oxidizer ,such as potassium nitrate, is necessary. A binder is a chemical compound that brings together the rest of the elements for an effective end result. Common binders used for sparklers are sugar and starch. When mixed with water, these chemical make a liquid mixture that can be added to a wire to dry over time (think of the wire of a sparkler). The fuel and oxidizer are added in a certain proportion so that the sparkler will burn for a long time rather than exploding. The iron or steel powder is used to create sparks that emit from the sparkler itself.

The Science Behind Fireworks, fireworks, sparklers, science, gunpowder, sulfur, stem, stars, shells, explosion, burst, light, show, fireworks, sparklers, science, gunpowder, sulfur, stem, stars, shells, explosion, burst, light, show
Firework sparklers are a staple of any celebration

Firecrackers are not a new invention; in fact, they have existed for hundreds of years. Gunpowder is stuffed inside a tight paper casing with a fuse to form a firecracker. Gunpowder consists of charcoal, sulfur, and potassium nitrate, so it already has two out of three parts necessary for combustion. When the fuse is lit and heat is added to the inside of the firecracker, combustion occurs and the firecracker explodes.

A firework at a firework display (commonly known as an aerial firework) consists of four parts made into a shell: Container, stars, bursting charge, and fuse. A shell is launched from a mortar, which is a steel pipe containing gunpowder. The gunpowder explodes and launches the shell while simultaneously lighting the fuse of the firework. As the shell climbs to its maximum altitude, the burning fuse reaches the bursting charge, which has a mechanism similar to the firecracker. The bursting charge ignites, exploding the firework and creating a wonderful sight for everyone to see.

The firework explosion is already magnificent, but firework stars create the signature trail effect that is often synonymous with fireworks. The stars are made up of the same chemical compounds that make up sparklers, but they are compacted into balls the size of a pea. The explosion of the firework ignites and scatters the firework stars, resulting in a marvelous firework show.

Some fireworks are more complicated, like multi-break shells which explode in multiple phases and may create crackling and whistling noises while exploding. Patterns can also be generated with firework stars by arranging them in a specific order inside the firework shell. Fireworks with interesting effects can be created with various elements of the periodic table. For example, barium is used for green colors, magnesium is used to add to the overall brilliance of the firework, and calcium deepens all of the colors. Evidently, there are nearly infinite ways to customize the designs and patterns of a firework in order to create the best display for people to enjoy.


Brain, M. (2000, June 30). How Fireworks Work. HowStuffWorks. Retrieved from

ScienceMadeFun. (2016, June 29). Fireworks and Their Colors. Retrieved from

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