The gorgeous fireworks you see are actually "electrons" dancing

During festivals or grand events, fireworks are often set off in various places to add to the atmosphere.

When the colorful fireworks bloomed in the dark night, accompanied by a loud "bang", the fireworks soared into the sky. In an instant, red, yellow, purple, blue and other colors of fireworks crisscrossed like falling meteors.

When we feel joyful and happy, have we ever thought about how these colorful colors are formed?

The structure of fireworks

Fireworks, also known as fireworks and fireworks, have existed since the invention of gunpowder, so they can be regarded as one of the four great inventions of ancient China.

The structures of fireworks and firecrackers are very similar. Both use black gunpowder as the fuse. When the gunpowder explodes in space, it will send the fireworks high into the sky. When the gunpowder burns and explodes in the sky, fireworks are formed.

Image source: hippopx

Fireworks Effect

The reason why fireworks can bloom in colorful shapes is mainly due to the "flame color" reaction. During the process of making fireworks, the production staff will add some metallic luminescent agents and coloring agents in a certain amount.

Metallic luminescent agents are mainly aluminum powder and magnesium powder, which emit dazzling white light when fully burned in oxygen. Colorants are mainly some metal compounds, and the metals in the metal compounds react violently with oxygen ions to produce light of different colors.

What is flame color reaction? Flame color reaction is also called flame color test and flame color experiment. It is a reaction that makes the flame show special colors when certain metals or their volatile compounds burn in a colorless flame. The principle of flame color reaction is the "identity card" contained in each chemical element - characteristic spectrum.

Since certain spectral lines in the spectra of elements such as sodium and strontium dominate, the flame color reaction is extremely obvious, and colored fireworks usually use these metal elements.

Speaking of this, many people will think that this is a chemical reaction, but the fact is: the flame color reaction is a physical change.

Because no new substance is generated, the changes are mainly caused by the change of electronic energy levels inside the substance, and do not involve changes in the chemical properties and the structure of the substance itself.

Different types of metal compounds produce different colors when they burn in the air, so we often use the color produced after combustion to identify which metal compound it is.

Here are some common colors as examples: the flame color produced when sodium burns is yellow, copper is green, and potassium is usually light purple. However, since potassium is usually doped with sodium, we often use blue cobalt glass for observation.

People who make fireworks will cleverly arrange these substances to determine the order of burning. The colorful and brilliant fireworks we see are actually "electrons" dancing.

Image source: hippopx

Now that we have a clear idea of ​​the colors of the fireworks, let's move on to a deeper understanding of the sound effects of the fireworks.

When gunpowder explodes in space, it produces a large amount of gas. Some gases can make pleasant flute and whistle sounds when they pass through the gaps in the nozzles. Some gases have stronger explosion power and can directly shatter the container to produce blasting sounds and "aftershock" buzzing sounds.

In layman's terms, the sound effects of fireworks are produced in a similar principle to that of wind instruments, where different instruments can produce different timbres under airflow.

Invisible killer of the atmosphere: Fireworks

Although fireworks are beautiful, they release a lot of air pollutants during the process of setting them off. The main components of "acid rain": sulfur dioxide, nitric oxide, nitrogen dioxide, etc., are gases produced when fireworks are set off. These gases not only harm the atmosphere, but also affect the human respiratory and cardiovascular systems.

In 1990, fireworks and firecrackers were set off in Dandong City, Liaoning Province on the eve of the Spring Festival. According to the test conducted by the environmental protection station staff, the harm caused by these gases was equivalent to a major pollution accident. With the development of the times and the advancement of science and technology, more and more people began to care about environmental protection issues, and thus electronic fireworks were born.

Electronic fireworks do not use black powder and lead, but use internal electronic components, light reflectors and confetti to produce the colorful explosions of traditional fireworks. For example, Hebei Province held an electronic fireworks exhibition. After the exhibition, there was not only no pungent smell from excessive gunpowder burning, but also no garbage from traditional fireworks. Electronic fireworks can also be recycled, which can be said to be both environmentally friendly and beautiful.

But compared to traditional fireworks, since electronic fireworks are a newly developed product, they are not widely popular in the market and are not available to the general public.

Image source: hippopx

In the past, fireworks were set off to ward off evil spirits, but nowadays, fireworks are more about noise and air pollution. Although fireworks are colorful, we should try to avoid putting too much burden on the environment.

END

Audit Expert

Sun Yafei, PhD in Chemistry from Tsinghua University.

Tadpole Musical Notation original article, please indicate the source when reprinting

Editor/Heart and Paper