Fireworks are a familiar sight to most people in the modern day. They’re used to celebrate many holidays around the world from the Fourth of July to Chinese New Year. What you may not know is that fireworks are an invention roughly 2,000 years old.
The first fireworks were created in Liuyang, China during the second century B.C.E. These fireworks, more similar to small firecrackers rather than the colorful displays we think of, were simple bamboo stalks that would explode when the air inside the stalk was heated by a fire. Several hundred years later, “black powder” (what you may know as gunpowder) was developed by a Chinese alchemist. This extremely explosive powder, a mix of potassium nitrate, sulfur, and charcoal, has been used to make fireworks ever since.
Though it may seem simple, there is actually a pretty complex chemical reaction going on when a firework is lit. Out of all of the ingredients used in the black powder, the sulfur melts first at around 250 degrees Fahrenheit. It then covers the potassium nitrate and charcoal, which helps them ignite. The ignition of these chemicals, a combustion reaction, creates a large amount of gas and energy, resulting in an explosion that propels the firework into the air.
To make different types of fireworks, even more precision is involved. Changing the size of the space the powder is confined to and creating or removing a hole for the gas to escape from affects whether it ignites and explodes or launches into the air. The size of the powder granules also affects how the firework reacts: large granules burn long and slowly while small granules burn much more quickly. Both of these components can be used to change the appearance of the explosion—consider the differences between the fireworks you’ve seen in your life. They often look very different from each other even though they are made with the same materials.
Now you may be wondering about the colors of fireworks, they’re one of the coolest things about them after all. As it turns out, the different colors come from the other elements found within the firework. Early fireworks barely left the ground and did not involve color, simply the explosion and the accompanying boom. However, as firework technology developed, color was eventually introduced.
At first, fireworks were only orange, which makes sense if you consider how they are lit. This wasn’t enough for most people though, and European scientists soon began using various metals to change the color. For example, adding strontium makes the explosion red, barium creates green, and copper makes it blue. Using these metallic elements to change the color works because when they are heated, the electrons within the metal’s atoms gain and release energy as light, which can range through the entire color spectrum.
Though fireworks started as a simple noisemaker in ancient China, they have evolved over many centuries to become the bright celebrators we know today.
About the Author
Oliver Ewy is a Senior in high school with an interest in science, specifically in biology and medical-related sciences. He hopes that his articles will help others find an interest in the natural world and encourage them to pursue scientific careers.
Sources
Gillespie, A. (n.d.). History of fireworks. American Pyrotechnics Association. Retrieved October 23, 2022, from https://www.americanpyro.com/history-of-fireworks
M.E. Bond. (2020, May 19). The long (orange) history of Fireworks. M.E. Bond. Retrieved October 23, 2022, from http://www.mebondbooks.com/2020/05/18/the-long-orange-history-of-fireworks/
Smith, P. E. (2021, December 21). How do fireworks work? A pyrotechnics chemist explains the science behind the brilliant colors and sounds. The Conversation: In-depth analysis, research, news and ideas from leading academics and researchers. Retrieved October 23, 2022, from https://theconversation.com/amp/how-do-fireworks-work-a-pyrotechnics-chemist-explains-the-science-behind-the-brilliant-colors-and-sounds-173576
Stempien, A. (2017, May 18). The evolution of Fireworks. Smithsonian Science Education Center. Retrieved October 23, 2022, from https://ssec.si.edu/stemvisions-blog/evolution-fireworks
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