An ancient explosive: Fireworks

A mixture of chemicals was used for the first time to make a low level of explosives in China before 1000 A.D. Fireworks were used in military explosive and construction blasting. The main company for making fireworks is DuPont company, which took Lavoisier’s invention who discovered oxygen as a key substance in combustion. Fireworks are a black powder that consists of potassium nitrate, charcoal and sulfur.

However, recently, in the nineteenth century, fireworks were confined mainly to rockets and boisterous blasts. The pyrotechnic stars are pellets that contain metal powder, salts and various compounds that produce different colors when ignited. The existing charcoal and iron filings in black powder are mainly responsible for the colors orange and yellow. With the great inventions of the elements in chemistry in the nineteenth century, new compounds developed the brilliant colors of fireworks, such as salts of copper, strontium and barium. Magnesium and aluminum metals made the bright white color in fireworks. 

There are two main components in fireworks, an oxidizer and a fuel. The oxidizer reacts with the fuel to produce heat (exothermic reaction). Subsequently, the gases expand rapidly (noise), while the other elements produced colors by releasing an electron from the shells of the visible spectrum. When exposed to exothermic heat, each compound creates a unique wavelength with a specific color. Sodium ions emit at 589 nm, which gives fireworks their yellow color. Strontium salts emit at 606 nm and from 636 to 688 nm, resulting in red colors. The color red is familiar with highway safety flares. The use of barium salts has a green color due to a succession of emission lines between 505 and 535 nm. The oxidizing agent, such as potassium chloride may react with copper and form copper chloride being considered an explosive compound and dangerous during storage. In recent years the colors produced by fireworks become more intense due to the formation of metal chlorides during the combustion process.