The spectacular fireworks, during which hundreds of colored lights dance in the sky, are not magic, but the meticulous work of pyrotechnicians, whose secret lies in the correct choice of the chemical components of the explosive mixtures.
The art of fireworks has come down to us since ancient times, with the oldest evidence of a "fire show" dating back to the 12th century AD However, not all are arranged in the same way, and anyone who has ever seen a spectacular barrage of multicolored lights at least once in your life will confirm this. The color of the explosion of a projectile filled with explosives depends on the chemical elements that make up its composition. It can be both ordinary metals, and salts, and even rare minerals.
A flash of colored flame is called a "star" in pyrotechnics. It consists of a mixture of fuel, oxidizer (to make the fuel burn), color-forming elements (more on these later), and a binder (usually glue) packaged in a lightweight package.
The yellow color is achieved by adding sodium. We're used to seeing it combined with chlorine in packets labeled "Salt," but when heated, pure sodium produces a bright yellow explosion that's perfect for lighting up the night sky.
- The red color of the flame is given by strontium. In the past, it was often added to the glass from which television screens were made, as it blocked a significant proportion of the radiation. In pure sierra, the element has a yellowish color, but its flame is bright red.
- The green fireworks are the result of an explosion of barium salts. For these purposes, barium nitrate is best suited, but its vapors are poisonous. Therefore, this substance is practically not used today in domestic pyrotechnics, but it can be found in combat grenades.
- The blue fireworks are the hardest. Copper creates the color blue. A very precise flame temperature is needed to obtain the blue color. It is a set of physical and chemical restrictions that prevent this phenomenon.
- The white flame is aluminum or magnesium. These elements release an incredible amount of energy when burned, and by adding them to other mixes, a “cleared” flame with pleasing light undertones can be achieved.
- There are many other connections. So the combination of copper and strontium will give a purple tint, and the secret to golden fireworks is, oddly enough, carbon.
More recently, pyrotechnicians have begun to use a technique called "halo", in which different colors are superimposed, delineating the mixtures with thin interlayers inside the projectile. In this way, you can create the illusion that multi-colored sparkles seem to be dancing in the sky - it looks captivating.
What is left after the explosion? As a rule of thumb, only a charred cardboard casing makes it to the ground at best. For the audience, this part of the show is the least exciting, but when they see the coals, the pyrotechnicians rejoice, they know that the working day is coming to an end.