How do fireworks work?

On major holidays around the world, fireworks are always put on display in public places with spectacular sights of color and sound.

So how do fireworks work? How can fireworks create brilliant colors in the night sky? Basically, just having cannonballs, gunpowder, burning wire, burning particles and especially accurate calculation will do it. How are the details? Please see below.

Fireworks are said to have originated in the Han dynasty, China thousands of years ago. Then it was simply made by stuffing gunpowder into a bamboo tube and throwing it into the fire. (see also the History of Fireworks Invention). As for modern cannonballs today, the bamboo tube has been replaced by a shell, which contains an explosive mixture and slow-burning wire. But that’s just the basics and still not enough, there are many other small but important components as well.

For modern pyrotechnic technology, it is required to create more and more splendid, sparkling and shimmering explosions . In addition to the sound of explosions, people increasingly want to emphasize the color element, creating more beautiful and monumental shapes. And historically, it was not until the Italian renaissance that people could create more colors for fireworks by adding steel powder and charcoal to create yellow and orange colors.

Gradually, pyrotechnicists experimented with adding more metals so that when they burned, they absorbed the energy from the explosion and gave off color. For example, adding Strontium makes red, Barium produces green and copper produces blue. These combinations and many other metals create the wide range of colors you see in professional fireworks displays.

To shoot fireworks into the sky, pyrotechnic artists will create a chain of 2 explosions. First the cannon will be placed in the launcher (motar). At the bottom of the cannon there is a separate compartment containing gunpowder and this gunpowder pack will be quickly detonated so that the cannon is launched into the sky without exploding the entire cannon. So what’s inside the cannon?

Cannon construction

How do fireworks work?

Basically, a regular cannon consists of a shell, usually made of plastic or paper, and this is where everything inside is stored. Inside the cannon are gunpowder and burning particles (Stars). These flammable particles are arranged around in a pattern depending on the shape of the explosion that one wants. Flammable particles are coated with a metal layer to give color when the burning particles are ignited. At the same time, the shape and size of the fire particles will determine the effect, the overall shape of the explosion in the sky (such as forming a star, circle, coconut tree, falling, …)

Another component is the slow-burning wire running along the firework. When launched, the propellant explosion also activates the slow-fire wire and it will slowly burn. The length of the slow-burning wire will be precisely calculated so that the firework explodes at the desired height, neither sooner nor later. For more complex cannons, an explosion chain is also created by connecting multiple slow-burning wires to detonate separate compartments in a firecracker.

Fireworks technology is still evolving. Now, some fireworks designers have begun using compressed air instead of conventional gunpowder to increase safety and create explosions that can be calculated more accurately. On the other hand, people are also looking to make fireworks displays more environmentally friendly by replacing a variety of new materials. Currently, the chemicals that color fireworks are all heavy metals, which can be toxic and affect human health as well as the ecosystem below the ground.

Therefore, people still have a lot of work to do to perfect this art. So far, we’re still basically using cannons from the 7th century, but of course, it makes for a much more beautiful explosion. Finally, we invite you to watch the fireworks display performed in the US recently.