Fireworks are an integral part of celebrations around the world – Bonfire Night in the UK, a range of Independence Days, weddings and birthdays – but their original use was in New Year’s celebrations.
The story of their invention is of a Chinese cook who accidentally spilled saltpetre – an ingredient in gunpowder which was sometimes used as a flavouring salt in cooking – into a cooking fire. The saltpetre mixed with the other ingredients of gunpowder – charcoal and sulphur – which were common in early fires – and produced a colourful flame.
The invention of gunpowder is thought to have occurred about 2000 years ago, with exploding firecrackers produced later during the Song dynasty (960-1279) by a Chinese monk from Hunan Province. The firecrackers consisted of bamboo shoots filled with gunpowder, which were exploded at the start of the new year to scare away evil spirits.
These days, the most important aspects of fireworks are the light and colours, but loud noise (known as “bian pao”) was the major element in these early fireworks, to ensure they frightened the spirits.
As well as being used to scare spirits in New Year’s and later other festivals, there was an obvious use of gunpowder in military operations once propulsion was added in the form of wooden rockets. It was in this way, and from early explorers, that the knowledge was brought to other parts of the world.
In many ways, fireworks are made much as they were hundreds of years ago, although, as mentioned, the focus today is far more on spectacular colours and light effects.
Today, fireworks can be launched using compressed air rather than gunpowder, with electronic timers to explode the shells, allowing accuracy in timing, so shows could be put to music, and reducing smoke and fumes from big displays.
So where do the red, orange, yellow, green, blue and purple colours exploding into our night skies come from?
The answer is chemistry. The colours in fireworks are created by the use of metal salts. The metal salts are packed into a firework as pea- to plum-sized pellets called “stars.”
Components in Fireworks
Aluminium – used to produce silver and white flames and sparks. It is a common component of sparklers.
Antimony – used to create glitter effects.
Barium – used to create green colours in fireworks, and to add stability.
Calcium – used to deepen the colours, and calcium salts produce orange fireworks.
Carbon – one of the main components of black powder, which is used as a propellant in fireworks. Carbon provides the fuel for a firework. Common forms include carbon black, sugar, or starch.
Chlorine – an important component of many oxidizers in fireworks. Several of the metal salts that produce colours contain chlorine.
Copper – Copper compounds produce blue colours in fireworks.
Iron – used to produce sparks. The heat of the metal determines the colour of the sparks.
Lithium – (in particular, Li carbonate) used to impart a red colour to fireworks.
Magnesium – burns a very bright white, so it is used to add white sparks or improve the overall brilliance of a firework.
Oxygen – Fireworks include oxidizers, which are substances that produce oxygen, in order for burning to occur. Sometimes the same substance is used to provide oxygen and colour.
Phosphorus – burns spontaneously in air and is also responsible for some glow-in-the-dark effects. It may be a component of a firework’s fuel.
Potassium – helps to oxidize firework mixtures.
Sodium – Sodium imparts a gold or yellow colour to fireworks, sometimes so bright it obscures other colours.
Sulphur – a component of black powder. It is found in a firework’s propellant/fuel.
Strontium – Strontium salts impart a red colour and its compounds are important for stabilising the firework mixtures.
Titanium – Titanium metal can be burned as powder or flakes to produce silver sparks.
Zinc – used to create smoke effects for fireworks and other pyrotechnic devices.
Helmenstine, Anne Marie, Ph.D. “Elements in Fireworks.” ThoughtCo, Jun. 22, 2018, thoughtco.com/elements-in-fireworks-607342.
Helmenstine, Anne Marie, Ph.D. “Chemistry of Firework Colors.” ThoughtCo, May. 14, 2018, thoughtco.com/chemistry-of-firework-colors-607341.
Helmenstine, Anne Marie, Ph.D. “History of the Invention of Fireworks.” ThoughtCo, Dec. 26, 2018, thoughtco.com/invention-of-fireworks-607752.