When you talk about Deepavali the first thing that comes to our mind is “Fireworks” and the enormous amount of fun we would have in this festival. The beautifully decorated houses with varieties of lamps, the awesome lip-smacking food, the night sky brightened up with colorful aerial fireworks and of course the sound of fireworks.
Lighting crackers is a ubiquitous tradition followed in order to celebrate the destruction of evil. The firecracker is an age-old ancient invention, which surely wouldn’t find its way if invented in the present situation as it produces tremendous sound, heat, and bright light. Fortunately, its ancient invention has allowed us to enjoy the dazzling view of aerial fireworks.
Do you know what makes the crackers sound so loud? What makes it colorful? Of course, we know that chemicals are the reason behind it. But are you aware of which chemicals are used?
What makes the different colors and sounds of different fireworks?
Aerial fireworks are the most vibrant and liked by everyone. But what makes this firework have such vivid colors and designs when it is fired / Lit?
The varied color emitted from fireworks is due to the burning of metal salts like Calcium chloride or Sodium Nitrate that emit characteristic colors.
Every Element and Compound has its own characteristic color when subjected to burning or fire. When introduced to heat, atoms of each element absorbs energy and electron jumps from the ground state i.e. the lower energy state to the higher or excited state releasing the excess energy in the form of light.
Why is Sound produced when you burst Crackers?
When asked about what causes the sound of fireworks, the first thing that comes to our mind is gunpowder. Yes, gunpowder causes a massive explosion and gives out a sound when burnt. but, gunpowder is not the only thing that produces sound in fireworks.
Many of the chemicals used in fireworks also produce sound when heated up. It is possible to create various sounds for various fireworks by controlling the explosion of chemicals and the way they are released.
The enormous sound heard is the result of the rapid energy in the air which causes faster expansion of air than the speed of sound.
Here is the list of chemicals and the colors they give out on burning or heating.
| COLOUR | Chemical Compound | |
 | Silver | Burning Aluminium, Titanium, or Magnesium |
 | Red | Lithium carbonate and Strontium Carbonate |
 | Green | Barium Compounds along with Barium chloride |
 | Blue | Copper compounds along with Copper chloride |
 | Yellow | Sodium salts along with Sodium chloride |
 | Orange | Calcium, iron salts along with Calcium chloride |
 | Purple | A mixture of Strontium and Copper compounds |
Have you ever thought about how sparklers work?
Sparklers are majorly composed of metal fuel, oxidizers, and binders. These three are the primary composition, yet, additional compounds can be added to this mixture to enhance the effect.
The body of the sparkler is made up of copper and the mixture is coated around the body.
Metal nitrates, and chlorates with potassium nitrate are the most commonly used oxidizers in the sparkler.
The oxidizer is the most important part which produces the sparkling effect in the sparklers. When heated, all these compounds decompose to give out oxygen and burning metal powder.
Metal fuel used in the mixture is responsible for producing different colors of the sparklers. Where Aluminium, Magnesium, or Titanium gives out a bright silver spark; Lithium, Strontium gives variations of red; Iron salts give out an orange spark, and whilst ferrotitanium and sodium salts give yellow sparkle.
These are the generally used colors in the sparkle; again, more variations of colors can be obtained by adding optional colorants.
What would be the use of oxidizer and metal powder if they are not bound together in the form of paste?
Yes, it’s the binder that enables us to make the paste that is coated around the metal wire which then becomes our sparkler.
Dextrin is the most commonly used binder. Dextrin is produced by starch hydrolysis.
The chemical mixture along with the binder is made into a paste with the use of water and then dried. And after drying we get the fantastic sparklers.
Hope now you know why Fireworks are Colourful. Do enjoy your festival lighting them. Please make sure that all the safety measures are taken into the consideration.
Have Fun!!
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