We all love fireworks, they bring a lot of enjoyment to parties, birthdays, weddings and public displays. While the bursts of colour and dazzling effects are often over in a few seconds, the craft that has gone into creating the vibrant hues in the night sky , takes quite a bit of chemistry.
From brilliant blues to fiery reds and dazzling greens, each hue is meticulously crafted through a delicate balance of chemistry and physics. In this guide, we will explain how each firework colour is made.
The Chemistry of Fireworks
Inside every firework, a clever blend of chemicals awaits its moment to shine. These compounds, primarily metal salts and metal oxides, are strategically nestled within the pyrotechnic devices, ready to unleash a vivid display of colours upon ignition.
As the gunpowder ignites, it sets off a chain reaction with these chemicals. This process excites the atoms in these compounds, causing their electrons to rearrange.
As these electrons transition from a high-energy state to a lower one, they release excess energy in the form of light. Each chemical emits light at specific wavelengths, dictating the hues we perceive.
How light waves work in fireworks
You might know that light travels in waves. Exploiting the differences in the wavelength creates the differences in colour. The different chemicals used in fireworks are chosen based on the kind of wavelength the released energy produces.
Metal salts and oxides with shorter wavelengths, around 400 to 500 nanometres, are used to produce different shades of blue. The salts and oxides with longer wavelengths, around 600 to 700 nanometres, create the bursts of red and orange colours. Finally, the wavelengths that fall between this, 500 to 600 nanometres, produce yellows and greens.
Pyrotechnic stars
A pyrotechnic star is a small, typically spherical pellet or shape composed of combustible chemicals that are used in fireworks. They are packed into larger fireworks shells and these are what are usually responsible for the colour of fireworks.
When these stars ignite, they burn and emit light, creating the stunning reds, blues, purples, and other vibrant hues that we all enjoy. Each of these stars contains five basic ingredients:
- Fuel: Burns to produce heat, light and gas
- Oxidiser: Provides oxygen for the combustion reaction
- Colourant: Adds colour to the flame by emitting specific wavelengths of light
- Binder: Holds the mixture together in the desired shape
- Additives: Additional substances added to modify the burn rate, strengthen and more..
Firework Colours
The key to producing specific colours in fireworks lies in the selection of chemical compounds. The chemical composition for each colour will naturally be different.
Understanding how firework colours are made adds to the excitement of watching them light up the sky. So, let’s dive into the rainbow of colours and discover the science behind the spectacle.
Red Fireworks
Chemical Compound: Strontium salts, typically strontium carbonate or strontium nitrate, are used to produce red fireworks.
How it Works: When strontium salts are ignited, they release red light. This happens because the electrons in the strontium atoms absorb energy from the firework’s ignition and move to higher energy levels. As they return to their original energy levels, they emit photons of red light.
Additional Information: Strontium is commonly used in fireworks due to its ability to produce a deep red colour. The intensity of the red can be adjusted by varying the concentration of strontium salts in the firework composition.
https://youtu.be/tIoug6fKjhk?si=uWsbReE6DFnN2D3S
Orange Fireworks
Chemical Compound: Calcium chloride or calcium sulfate is often used to create orange fireworks.
How it Works: When calcium compounds are heated, they emit light with a wavelength that appears orange to the human eye. This occurs due to the movement of electrons within the calcium atoms, similar to the process in red fireworks.
Additional Information: The colour produced by calcium compounds can vary depending on factors such as the specific compound used and the combustion conditions.
https://youtu.be/A2cba6MM05w?si=KJkNnYrSafkmlZAU
Yellow Fireworks
Chemical Compound: Sodium compounds, such as sodium nitrate or sodium chloride (table salt), are utilised to generate yellow fireworks.
How it Works: Sodium emits a bright yellow colour when heated. The excitation of sodium atoms during combustion leads to the emission of yellow light as electrons return to their original energy levels.
Additional Information: Sodium-based fireworks are known for their vibrant yellow hues, often seen in combination with other colours to create stunning visual displays.
https://youtu.be/_CdQNXO-5IY?si=eTeQgRsLYwVHW5Gs
Gold Fireworks
Chemical Compound: Gold is typically produced by adding iron filings to the firework composition.
How it Works: The golden colour in fireworks comes from iron atoms being heated to high temperatures during combustion. The energy absorbed by the iron atoms causes them to emit light with a golden hue as they return to their ground state.
Additional Information: Gold fireworks can vary in shade depending on the specific formulation and the combustion conditions, ranging from deep, rich gold to a lighter, more subtle hue.
https://youtu.be/YFZz5r57gNQ?si=UpsPW4z7Gp8BE6N_
Green Fireworks
Chemical Compound: Barium compounds, such as barium chloride or barium chlorate, are commonly used to create green fireworks.
How it Works: When barium compounds are ignited, they release a green light. This occurs due to the excitation and subsequent relaxation of electrons within the barium atoms.
Additional Information: Green fireworks are popular for their vibrant colour and are often used in combination with other colours to enhance visual effects.
https://youtu.be/xDpV4H0R16c?si=3Eqzpu2rT4SwMVx_
Blue Fireworks
Chemical Compound: Copper compounds, such as copper chloride or copper carbonate, are used to produce blue fireworks.
How it Works: Copper emits a blue colour when heated. During combustion, energy is absorbed by copper atoms, causing electrons to jump to higher energy levels. As these electrons return to their ground state, they emit blue light.
Additional Information: Blue fireworks can range from deep indigo hues to brighter shades of blue, depending on factors such as the specific copper compound used and the combustion conditions.
https://youtu.be/JHTt8f0AZNM?si=NuJcVL917VSy2_Rb
Purple Fireworks
Chemical Compound: Purple fireworks are often created by combining strontium (red) and copper (blue) compounds.
How it Works: The combination of red and blue light emitted by strontium and copper compounds creates the appearance of purple when viewed together.
Additional Information: Purple fireworks are achieved by carefully blending red and blue components to achieve the desired shade of purple, adding depth and richness to fireworks displays.
https://youtu.be/nGaLtHetMAI?si=JPR5wDMuqLeIP4yo
White Fireworks
Chemical Compound: White fireworks can be produced using a combination of metal powders, such as magnesium or aluminium, along with oxidisers like potassium perchlorate.
How it Works: The intense heat generated by the combustion of metal powders and oxidisers produces a brilliant white light. This occurs as the metal atoms emit light across the entire visible spectrum, appearing white to the human eye.
Additional Information: White fireworks are often used as highlights in displays and are prized for their ability to illuminate the night sky with a dazzling, pure-white brilliance.
https://youtu.be/jEA2IQ8DrnA?si=bLOlU-8HETpFKbfN
Naturally by mixing and matching these chemicals, you can create all sorts of variations of the colours. By using chemicals, manufacturers are also able to add special effects and enhance the colours. For example, by adding antimony to the fireworks, manufacturers can create the glittery effect. In addition, a hint of calcium and the colour is deepened, while phosphorous adds the glow-in-the-dark effect to fireworks.
The exciting thing is that firework manufacturers are constantly researching new chemical compositions to come up with all sorts of stunning colours and effects. It will be interesting to see how the science behind fireworks develops and what sorts of amazing creations will we be able to see in the years to come!
Order Colour Fireworks from Firework Crazy
As we wrap up our exploration into how fireworks dazzle us with their colours, it’s clear they’re more than just pretty lights. We’ve learned how each colour is made, from the reds that come from special salts to the blues from copper.
Understanding how fireworks get their colors makes us appreciate them even more. It’s not just about the show; it’s about the hard work and imagination that go into making each burst shine bright. When we watch fireworks, we’re not just seeing pretty lights. We’re joining people all over the world in celebrating special moments together.
So, next time you watch fireworks light up the night sky, remember the mix of science and art that makes them so special. It’s not just about the colors—it’s about the memories and happiness they bring to all of us.
