How difficult is it to produce the blue fireworks in the TV series "Nothing But Thirty"?

In the TV series “Nothing But Thirty”, “blue fireworks” are repeatedly mentioned as the highest dream of fireworks designer Xu Huanshan, and they continue to appear as an important element to promote the plot.

So, in reality, is it true that no one has ever made blue fireworks?

Of course not. By adding copper compounds, fireworks can be made blue.

However, blue fireworks are indeed the holy grail of the fireworks industry. Fireworks with pure blue color are not only beautiful, but also rare.

The picture is from Stephen Chow's movie "The Mermaid", and has been processed

Part 1

Why do fireworks have colors? Why are blue fireworks difficult to make?

To this day, pure blue fireworks are still a selling point in fireworks shows, and it is not an exaggeration to call them the holy grail of the fireworks industry .

Why are blue fireworks so rare?

First, we need to understand how fireworks are “colored”.

Can you remember the colors of common fireworks?

(Photo source: Veer Gallery)

Fireworks can present various colors, not because of the pigments we use for painting, but because of the addition of different metal compounds, which produce a physical change called "flame color reaction". Flame color reaction is the phenomenon that metal atoms or ions present different colors in the flame.

From left to right are the flame color reactions of barium, strontium, lithium, sodium, copper, and potassium (Source: Fine Art America)

When a metal element is placed in a flame, the outer electrons of the metal will absorb the flame energy and "jump" - that is, the electrons that originally had a stable orbit will reach an orbit with higher energy. This is like a batter in baseball swinging a bat to make the baseball that was originally flying straight towards him fly higher and farther.

However, the electrons after the transition are not stable, and they will immediately return to their previous lower energy state. This is like a baseball flying high, but it will eventually fall to the ground. This process is also called transition, but the direction of the transition is from a high energy orbit back to a low energy orbit. At this time, the electrons will release the energy they originally absorbed in the form of electromagnetic waves.

When electrons in atoms of different elements transition, they release electromagnetic waves of a specific wavelength. This wavelength is related to the specific element and is a characteristic property of the atom. The electromagnetic waves released by electrons in many metal atoms when they transition are just in the visible light band, so people can clearly see the colorful colors. This is the origin of the name of the flame color reaction.

The blue fireworks we see are actually countless electrons releasing energy in the form of blue light.

Generally, people use copper or copper compounds as colorants to produce blue, including copper powder, copper sulfate, copper carbonate, copper nitrate, copper hydroxide, basic copper carbonate, cuprous chloride, etc. Among them, the blue light with a wavelength of 420-460 nanometers released by cuprous chloride (CuCl) is the purest, because the blue produced by other copper salts usually has a distinct green hue.

Okay, now that we have explained the principles of blue fireworks, let’s get back to our topic: why are blue fireworks so difficult to make?

This is mainly caused by the following aspects.

First of all, although the night sky looks black, it actually still has a strong blue hue. It is not easy to make blue fireworks stand out from the background. Because a slight change in the composition will cause a great change in the combustion temperature and flame color, it is not easy to adjust the ratio of the pyrotechnics so that they can present the desired color. Blue fireworks also have to consider the contrast with the night sky background, so the difficulty can be imagined.

In addition, there is a natural contradiction that restricts the production of blue fireworks. Generally speaking, the higher the temperature of the pyrotechnic agent when it burns, the brighter the color of the flame reaction, and the better the visual perception. But at the same time, too high a temperature will cause the metal salts used as colorants to decompose, causing the state of the metal atoms to change and fail to release the expected color. The decomposition temperature of cuprous chloride, which is most likely to produce pure blue light, is only a few hundred degrees. When it undergoes a flame reaction, it has actually begun to decompose. Therefore, when you want to present blue light, it is best to control the temperature below 1200 degrees Celsius, otherwise other bright white colors will be produced, affecting the purity of the blue light.

But in the final analysis, the reason why blue fireworks are difficult to make is still related to the scarcity of materials . There are many kinds of inorganic metal salts corresponding to other colors, but cuprous chloride is almost the only one that can produce blue light. Of course, if we also include organic copper salts in the scope of investigation, then the options will indeed increase greatly. The problem is that the production of fireworks requires a lot of salts, and cost is a very critical factor, and organic salts are obviously too expensive.

Blue fireworks (Photo source: Lin Wencheng)

Humans have been trying for centuries to find a substitute for cuprous chloride, but to this day it is still the preferred raw material for blue fireworks. Fireworks engineers can only make the final blue color as bright and dazzling as possible by constantly adjusting the formula of the pyrotechnic agent. In this sense, the plot in the TV series does have a certain basis in reality, and I really want to applaud the screenwriter for his profound knowledge.

Part 2

“GJ”, “UU”… How are these firework patterns produced?

In addition to the manufacturing difficulties of blue fireworks, "spelling fireworks" also appeared in the TV series. In order to support the characters in the drama, some manufacturers also produced fireworks with the initials of the heroine's name in real life.

The fireworks on the left are from the drama, and the fireworks on the right are from real life. Both are spelling fireworks (Source: Weibo)

So, how are these spelling fireworks and the pattern fireworks we see in our daily lives made?

This brings us to the fireworks shells used in large fireworks.

Firework shells are a type of fireworks. The core part is the pyrotechnic agent, which is the agent that produces flames of various colors when burned. The main components of pyrotechnic agents include: oxidant, combustibles, colorants and adhesives. Its working principle is that the oxidant is decomposed by heat under the action of combustibles, and the released oxygen is used for further combustion of combustibles to generate high temperature, thereby promoting the (metal) colorant to react with flames, and the adhesive plays the role of bonding various components into a whole.

Colorants are usually composed of various metal salts that can produce flame color reactions. If you only need dazzling white light, you can also add brighteners represented by magnesium powder and aluminum powder. The temperature of ordinary fireworks when burning is around 2000 degrees Celsius, but after adding brighteners, the burning temperature can reach 3000 degrees Celsius, which can produce an extremely bright incandescent light.

Fireworks are usually spherical or ring-shaped, with the spherical pyrotechnics located on the outer periphery of the ball or ring, and the center is the gunpowder used for detonation, which is directly connected to the fuse. When the fireworks are loaded into the launch tube, there is actually a certain amount of propellant gunpowder in the tube, which is used to launch the fireworks into the air.

When the propellant ignites, the fuse is also ignited. When the fireworks shell rises to the predetermined height, the fuse burns into the inside of the fireworks shell, and then the detonating gunpowder explodes, and the combustible components in the pyrotechnic agent are ignited.

Fireworks shell structure

(Photo source: Kato Fireworks Co., Ltd.)

People often make fireworks into a multi-layer structure, with each layer from the outside to the inside containing a different composition of colorant. In this way, when an explosion occurs in the sky, the outer layer of colorant will explode first, followed by the middle layer, and finally the inner layer. The advantage of this is that the fireworks will show a clear staged color change effect , which enhances the viewing experience.

As for spelling fireworks and pattern fireworks, the main way to achieve the effect of spraying the pyrotechnic ball with different strengths and in different directions is to control the loading direction and amount of the detonating gunpowder.

Heart shaped fireworks structure

(Photo source: Kato Fireworks Co., Ltd.)

Part 3

Although fireworks are beautiful, we must always pay attention to safe storage and safe use

Osaka Yodogawa Fireworks Festival 2019

(Photo source: Lin Wencheng)

Fireworks are flammable and explosive items, and dangers may occur in every link of manufacturing, use and storage. Whether it is large-scale fireworks that need to be operated by professionals or ordinary civilian fireworks, they have caused many explosions and fire accidents. For fireworks manufacturers and professional fireworks display personnel, controlling every production and circulation link is a responsibility that must be fulfilled to ensure their own and public safety. For ordinary consumers, it is necessary to understand the hidden dangers that may occur in the setting off of fireworks. Common sense must be possessed.

There are three common safety issues when using large fireworks.

First, duds caused by failed fuses , which are loaded with a large amount of gunpowder, will eventually fall back to the ground. Although general fireworks displays will try to ensure that even if there are duds or residues falling, they will fall directly into the lake or sea, but if you really encounter a dud, you must contact the fire department immediately for treatment.

Second, ignition failure caused by igniter failure , electronic equipment is likely to malfunction. There have been many instances in history where fireworks shows failed or were terminated due to such reasons.

If temporary manual ignition is required at this time, the operator must be well protected. In addition, remote ignition must be performed when the charge exceeds a certain level.

Third, accidents such as the launch tube falling over may occur during the launch of fireworks, so it is necessary to ensure that the equipment is in the best condition in advance. For ordinary civilian fireworks, although the amount of powder is far less than that of large fireworks, the probability of danger cannot be ignored, and basic safety precautions must be followed.

First of all, it must be made clear that setting off fireworks in prohibited areas and during prohibited times is illegal . Before setting off fireworks, you must confirm the relevant information clearly. When setting off fireworks, you must not aim at people or other animals, and you must also pay attention to whether there are flammable and explosive items around. Before setting off fireworks, remember to check the weather forecast. Strong winds can easily cause fires, so you should avoid setting off fireworks under such weather conditions. When lighting a tubular firework, if it does not ignite smoothly, do not look directly at the firework's nozzle. Finally, it is very dangerous to disassemble the outer packaging of fireworks and then pour out the gunpowder to ignite it! We must pay attention to safety, strictly abide by relevant safety regulations, and cherish life and health.

People often use the phrase "life is like a summer flower" to describe the fleeting beauty, but fireworks are more ephemeral than summer flowers. The stars are like dreams, fireworks are easy to cool, and it is difficult to determine what will happen after the splendor. The fireworks designer in the TV series once had a lot, but in the end, they were all gone. Our lives are similar to fireworks. We should pursue the brilliance of fireworks when they bloom, but we must also remember to take every inconspicuous step in production and storage, otherwise, the next second of splendor may disappear into thin air.

References:

1. Blue Flame Pyrotechnic Compositions: A Concise Review

http://www.jpyro.co.uk/?p=1148

2. Why you don't see brilliantly blue fireworks

https://www.businessinsider.com/fireworks-blue-pyrotechnics-chemical-hard-make-2019-7

3. Red, white but rarely blue – the science of fireworks colors, explained

https://theconversation.com/red-white-but-rarely-blue-the-science-of-fireworks-colors-explained-119284

4. The Evolution of Fireworks

https://web.archive.org/web/20160106154801/https://ssec.si.edu/stemvisions-blog/evolution-fireworks

5. Why Blue Fireworks Are Hard to Make, According to Science

https://www.inverse.com/article/33623-blue-fireworks

Produced by: Science Popularization China

Produced by: Zhang Hao (Osaka University)

Producer: Computer Network Information Center, Chinese Academy of Sciences

(The images with source indicated in this article have been authorized)

The article only represents the author's views and does not represent the position of China Science Expo

This article was first published in China Science Expo (kepubolan)

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