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Exploring the chemistry of Fireworks

Have you ever wondered how all the different colors, such as red, yellow, blue, green and more, are made in fireworks displays? Creating firework colors require considerable art and application of physical science. The colors in fireworks stem from color-producing compounds present in it. So, how do these compounds give such a huge range of colors? Do we need anything else to produce fireworks? From lift-off to color release, the carefully choreographed sequence of events that takes place during fireworks displays require various chemical ingredients such as black powder, reducing agent, binder, coloring agent, oxidizing agent, reducer and fuel. The chemistry behind these ingredients has been explained below:

Fuel

Charcoal, which is commonly known as black powder is the most common fuel used in fireworks. In the pyrotechnic industry, black powder is made by crushing charcoal using ball mills. Modern black powder contains saltpeter, charcoal and sulfur in the weight ratio of 75:15:10. The combustion of black powder takes place as several oxidation and reduction reactions between oxidizers, reducers and other compounds.

Coloring Agents

Different chemicals or salts in fireworks produce different colors. So, the corresponding chemicals that can be used to produce a firework of a certain color are: strontium for red color; copper for blue; sodium for yellow; calcium for orange and barium for green. Metals are also added to fireworks in order to regulate the speed of the chemical reactions that takes place inside fireworks.

Oxidizing and Reducing agents

Nitrates, chlorates or perchlorates are used as oxidizing agents in order to produce the oxygen needed to burn the mixture inside the firework. Reducing agents burn the oxygen provided by the oxidizing agents, and the burning of oxygen produces hot gasses. Common reducing agents are sulfur and charcoal, which also act as fuel for the fireworks.

Binders

A paste like-structure that is used to hold the firework mixture together is called binder. Binders also separate elements which should not mix. Generally, dextrin is used as binder in fireworks, but sometimes, Paron is used as binder with red and green fireworks to enhance their color.

All the above mentioned ingredients have their own functions in producing the color and effect during fireworks displays. Other parameters such as grain size, powder composition and packing require the skill of manufacturer to produce the most spectacular effects and sounds at the time of final display. So, next time when you will attend any aerial fireworks show, think about the science involved in creating the spectacular display of fireworks that light the darkened sky!

This was posted in Bdaily's Members' News section by Joe Anderson .