Why are fireworks colorful? Fireworks and firecrackers are actually different

Expert of this article: Chu Yuhao, PhD of Beijing University of Chemical Technology, engineer of Sinopec Beijing Research Institute of Chemical Industry

When it comes to Chinese New Year, everyone will definitely think of fireworks and firecrackers. Beautiful fireworks light up the black night sky, and loud firecrackers set off a strong New Year atmosphere, accompanying us into the new year.

Today's fireworks are colorful and firecrackers are even more diverse, but have you ever thought about what these fireworks are made of? Why do they appear in various colors? What harm will excessive fireworks bring? Let's learn about it today.

What is the difference between fireworks and firecrackers?

We often associate fireworks and firecrackers together, so what is the difference between the two?

The biggest difference between fireworks and firecrackers is that firecrackers generally only contain gunpowder, while fireworks often contain color developers, brighteners and other chemical substances to achieve color effects.

In terms of danger, firecrackers are sealed after adding gunpowder, and will explode once ignited, which is more dangerous than fireworks.

What are fireworks made of?

The chemical composition of a complete firework mainly consists of four parts: oxidant, combustible, color developer and brightener.

Oxidants play the role of supporting combustion and releasing heat through oxidation, and mainly include nitrates and chlorates;

Combustibles mainly include carbon powder, sulfur, etc., which mainly play the role of combustion and energy provision;

The color developer is mainly composed of some metal salts such as sodium salts, copper salts, barium salts, etc., which are also the main source of the colorful colors of fireworks;

The function of brightener is to make fireworks brighter and more gorgeous, mainly by utilizing the bright white light produced by magnesium powder and aluminum powder when burning.

Why do fireworks come in different colors?

The colors of fireworks mainly come from the special flame colors produced by some metal salts when they burn. So why do they produce various colors when they burn? It turns out that this is the famous "flame color reaction" in chemistry.

Although the flame reaction involves the combustion of metal salts, it is actually a physical change in nature. In short, the principle of the flame reaction is that the metal salt releases the energy generated by the combustion in the form of light.

When part of the metal salt burns, the electrons outside the metal nucleus absorb energy and jump from a lower energy orbit to a higher energy orbit. This process is unstable and reversible. When the electrons return to their original orbits from high-energy orbits, they release the excess energy again in the form of light.

Different metal salts can release different wavelengths of light, which are reflected in our eyes as different colors of light. Therefore, adding different metal salts to fireworks will make the fireworks show different colors when burning.

Strontium salts and calcium salts are generally added to red fireworks; sodium salts are mainly added to yellow fireworks; potassium salts and lithium salts are mainly added to purple fireworks; copper salts and barium salts are mainly added to green fireworks. The flame color reaction of different metal salts, combined with the brilliant white light of brightener aluminum powder and magnesium powder when burning, makes our fireworks finally present brilliant and colorful colors.

What are the dangers of setting off fireworks?

Although fireworks are colorful and firecrackers can add to the festive atmosphere, in recent years many cities have begun to implement bans on the burning and setting off of fireworks and firecrackers in different areas. This is mainly because excessive use of fireworks and firecrackers can cause great harm to the human body and the environment.

Because fireworks contain large amounts of charcoal, sulfur and metal oxide powder, when they burn and explode they will produce large amounts of greenhouse gases and pollutants such as carbon dioxide, nitrogen oxides and sulfur dioxide, which will seriously affect the air quality.

At the same time, the metal oxides in fireworks and firecrackers will be suspended in the air to form harmful dust after the explosion, which will have a strong irritating effect on the human respiratory tract and eyes after inhalation. This is also the reason why the air quality is poor after setting off fireworks and firecrackers.

In addition to the fire and burns that may occur when setting off fireworks, the noise pollution caused by the explosion of fireworks cannot be ignored. Therefore, banning the burning and setting off of fireworks has positive significance for both residents' health and environmental protection.

In the past two years, something called "cold fireworks" has quietly emerged. Cold fireworks add metal powder with a lower ignition point, which achieves an effect similar to fireworks through combustion and spraying.

Although cold fireworks do not produce a lot of smoke when set off, the temperature of their nozzles is close to 700-800℃, which can easily cause burns to the human body and start a fire. At present, cold fireworks are included in the same control as traditional fireworks as flammable and explosive items, and we need to pay special attention to this.

Fireworks and firecrackers can bring us a festive atmosphere

There are also some hidden dangers

During the Chinese New Year

I hope everyone will follow the relevant regulations

Fire safely in the firing area

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