How do fireworks work?
The short answer
A series of explosions launch the firework into the air and then cause it to burst into colorful displays. The vibrant colors are produced by metal atoms that release light when their electrons get excited by the heat.
The long answer
Whether you "ooh" and "aah" at fireworks shows or would rather they not make such a ruckus, the science and mechanics behind them are pretty interesting!
There are many types of fireworks, but I'm going to focus on aerial fireworks. Aerial fireworks, the ones used in big shows, are shot off into this sky before they explode into bright colors.
The key ingredient of fireworks comes from black powder, a type of gunpowder. When black powder is ignited, it explodes!
In a nutshell, an aerial firework has three main explosions::
🧨 Lift charge: A layer of black powder at the base of the firework. This first explosion sends the firework shell into the air.
💥 Burst charge: A pocket of black powder inside the shell of the firework. This second explosion causes the firework stars (see below) to explode and go flying through the air.
🎆 Stars: Numerous small pellets that create bright, colorful lights when ignited. This final explosion is responsible for the dazzling affair.
In more detail, here are the steps of how a firework goes off:
Step 1: The fuse is lit, giving time for the pyromaniac to move to safety.
Step 2: The fuse sets off the lift charge. This does two things: It sends the aerial shell flying up into the air, and it lights the time delay fuse. The mortar guides the shell straight up.
Step 3: The time delay fuse is there to (you guessed it) add a time delay before the aerial shell explodes in the sky.
Step 4: Once the shell is high in the air, the time delay fuse ignites the burst charge.
Step 5: The burst charge explodes the aerial shell, sending the ignited stars flying in all directions.
Step 6: The stars themselves explode and create vibrant, colorful lights in the sky.
A three-part act: The shell ascends, the shell ignites, the stars explode into colorful lights.
How do fireworks get their color?
In essence, fireworks work thanks a series of well-timed explosions. But how do they create dazzling colors?
"Australia Day 2013 Perth 39" by Kaoz69 is licensed under CC BY-SA 3.0.
Fireworks get their colors from how different metals react to heat.
The intense heat from the star's explosion excites the electrons in the metal atoms. When electrons are excited to higher energy levels, they become unstable and quickly return to their original energy levels. As they drop back down into their ground state, they release the excess energy as light. This video clip does a great job of explaining this phenomenon in greater detail.
Different metals have different energy gaps, which correlates to the emission of different colors. Here's a breakdown of which metals are responsible for which colors in fireworks:
| Color | Metal |
|---|---|
| 🔴 Red | Strontium, lithium |
| 🟠 Orange | Calcium |
| 🟡 Yellow | Sodium |
| 🟢 Green | Barium |
| 🔵 Blue | Copper |
| 🟣 Violet | Potassium |
| 🌟 Gold | Charcoal, iron, lampblack |
| ⚪ White | Titanium, aluminum, magnesium |
For making it this far in the newsletter, you deserve a little treat. Here's my personal favorite fireworks video of the time of when all the fireworks planned for a Fourth of July show accidentally went off at the same time (don't worry, no one was harmed).
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Sources
Brunning, A. (2013, December 30). The chemistry of the colours of fireworks. Compound Interest. https://www.compoundchem.com/2013/12/30/the-chemistry-of-fireworks/
Government of Ontario. (n.d.). The Science of Fireworks. Ontario Science Centre. https://www.ontariosciencecentre.ca/science-at-home/diy-science-fun/the-science-of-fireworks
Learn from the base. (2021, May 27). HOW THE AERIAL SHELL FIREWORKS WORK? || PROFESSIONAL FIREWORKS | 3D ANIMATION || LEARN FROM THE BASE. YouTube. https://www.youtube.com/watch?v=DPPqpS0y3rs
Muller, D. (2023, July 7). The Hidden Science of Fireworks. YouTube. https://www.youtube.com/watch?v=lfkjm2YRG-Q
The Library of Congress. (2019, November 19). How do fireworks work?. The Library of Congress. https://www.loc.gov/everyday-mysteries/chemistry/item/how-do-fireworks-work
Tockstein, M. (2020, July 1). How Fireworks Work. YouTube. https://www.youtube.com/watch?v=Ogk9cCv4-Qo
It’s like an American accent but with calendars.