A loud streak pierces the night sky. The glowing tail of the rocket captures your attention as it soars into the stars. After a second delay, the tail disappears only to reveal an even bigger BOOM! Suddenly the dark sky is injected with brilliant sparks, sounds, shapes, and colors. As dozens of them dot and scatter across the heavens, you think to yourself, “This is the best fireworks show yet!”
Fireworks have been around for almost 2000 years. The Chinese are accredited for being the original creators and discoverers of fireworks. Legend tells of a cook who accidentally combined saltpeter (a salt-like substance) into a fire. Saltpeter is a common element that is now used in gunpowder. The cook noticed that the saltpeter, once put into the fire, started to react and give off an interesting, yet captivating, glow. In order to contain his mistaken chemical reaction, the cook poured his mixture into a bamboo tube. When the tube was sealed, the elements inside ignited, causing them to explode out of the tube! And that is apparently when the
first firework was created. Fast forwarding almost 1000 years later, a new gentleman is introduced into the firework industry, a monk by the name of Li Tian. It was through his work that he created “firecrackers”. These firecrackers were much different then than ours our now. Typically a Chinese firecracker was a large bamboo shoot stuffed with gunpowder and once lit, it exploded. After several years, the rocket was invented. This caused the firework to be launched into the air instead of exploding on the ground. Colorful fireworks were not invented for several more years. Different additions and types of fireworks have been developed over the centuries. Although the history of the firework is fascinating, the chemistry behind the firework is equally as captivating.
There are typically five parts of a firework. When dissecting an aerial firework, we first look at these steps. Step one: the stick/tail. This enables the firework to go towards its intended location and stay straight. Step two: the fuse. The fuse is the part of the firework body which, when
ignited, lights the firework. Step three: The charge. This is the most important part of the firework process. The firework is first loaded with gunpowder which is what makes the firework BOOM! Gun powder by itself won’t be able to launch the firework so it is also mixed with reactant elements such as sulfur and nitrate. Other elements known as “oxidizing agents” are combined in order to create oxygen for the gunpowder to burn. These oxidizing agents are typically “nitrate, chlorates, or perchlorate”. Step four: Effect. The effect is what makes the firework so captivating. The sides of the shell are lined with elements known as “stars”. These stars, when lit, enable the firework to explode with color, sparkle, and sound. Each firework is different based on the organization and position of the stars in the shell. The fifth and final step is: the head or cover. The head is what keeps all of the ingredients and mixtures inside the firework. The typical sharp end of the head helps direct the firework when it is launched.
There are two leading terms which define the coloring of fireworks. (1) Incandescence which is “light produced from heat”
(Thoughtco). And (2) Fluorescence which is defined as “light produced using other sources than heat” (Thoughtco). Each mixture contains different elements and “propellers” which create different colors and reactions in the firework. Some examples of these elements are calcium chloride, barium oxide, magnesium, and more. No color has the same mixture. In an article by compoundchem.com, “Each color has different reactant names for the elements used for that color”. For example, Red: strontium salts, Orange: ‘calcium salts’, Yellow: ‘sodium salts’, Green: ‘barium salts’, Blue: ‘copper salts’, and white: ‘burning metals’. Regular and simple colors just use pure elements but those that are mixed to create colors such as purple or silver, are combined with other elements. In a firework, the color elements and salts are formed inside the “stars”. When the “stars” inside the firework are lit, they create the chemical reaction in the firework and cause it to explode. An article by live science.com gives a perfect description as to how the salts and oxidizing agents react to each other inside the “stars”. “When (a specific element) is heated, electrons in the sodium atoms absorb the energy and get
excited. As the electrons come down from the high, they release their energy,”(livescience.com). So in other words, when we see a firework being launched into the sky, we can realize that while it is flying into the air, the reactants inside the firework are being lit. Once the chemical element is ignited, the salt mixture contains the energy and then begins to move. The more movement created, the more the electrons are being used and therefore giving off energy in order to produce an EXPLOSION!
Fireworks are some of the most captivating and breathtaking experiences we are able to witness. No matter how old one may get, you can never grow out of watching fireworks. It’s fascinating to discover the scientific and chemical process behind the making of one as well! Through multiple mixtures of gunpowder, saltpeter, oxidizing agents, and fire, it is amazing how complex a firework is to create. Although almost all fireworks are created differently and individually, it is always amazing how each one is able to draw the same reaction, “OOOOOO…AHHHHHHHH!!!