A firework is a device that uses combustion or explosion to produce a visual or auditory effect. Modern pyrotechnics also includes devices similar to fireworks, such as flares, matches, and even solid-fuel rocket boosters used in spaceflight.
The earliest ancestors of fireworks were paper or bamboo tubes filled with finely grourid charcoal and sulfur used in China two thousand years ago. These tubes produced a flash of fire and smoke when ignited, but no explosion. True fireworks did not exist until saltpeter was added to the mixture to create black powder, the first chemical explosive, one thousand years later. Black powder was probably first made in China, but some scholars suggest that it may have been invented by the Arabs.
The Chinese used black powder for fire-works, signals, and weapons such as bombs and rockets. Black powder was introduced to Europe in the 14th century as an explosive for both fireworks and guns. It was applied to mining and roadbuilding projects by the late 17th century. Black powder was used for gunpowder until it was replaced by nitrocellulose in the late 19th century, and (for industrial purposes) by dynamite in the early 20th century, but it is still used in fire-works today.
Fireworks in China evolved from simple firecrackers to the extravagant displays witnessed by European explorers in the 16th century. In Europe, fireworks began with military explosives adapted for use in celebrating victories and progressed to the elaborate productions designed by Italian pyrotechnists in the 16th, 17th, and 18th centuries. (Even today, most of the large fire-work companies in the United States are run by Italian-American families.) These Italian fireworks were usually shown on lavishly decorated wooden sets, often floating on bodies of water, both for safety and to reflect the beautiful displays. On the other hand, German fireworks of the time were usually shot into the air, much like today's fireworks.
Although the firework displays of the Italian masters were extremely complex and impressive works of art, the technology of the time limited their color and brightness. During the 19th century, the introduction of aluminum and magnesium greatly increased the brightness, while the development of potassium chlorate by the French chemist Claude-Louis Berthollet (who was trying to improve the gunpowder used by Napoleon's troops) made it possible to produce more intense colors.
Fireworks came to the New World with the earliest settlers, and have been used to celebrate Independence Day, July 4, since the earliest days of the United States. During the early 20th century these fireworks became bigger, more powerful, and dangerous. Between 1900 and 1930 more than 4,000 people were killed by fireworks. Federal and state governments began regulating the use of fireworks in the 1930s. Explosives are classified as Class A (dangerous substances such as dynamite and TNT), Class B (fireworks used for professional displays) and Class C (smaller fireworks intended for private use.) Class C fireworks must not contain more than 50 milligrams of explosive. Some states allow all Class C
While the private use of fireworks is heavily restricted, public displays have become more and more elaborate. Computers are used to time fireworks precisely, so they can be choreographed in time to music. Lasers are sometimes used to produce unique visual effects. Today fireworks are made and displayed around the world, particularly in Europe, Latin America, the United States, and Japan.
A modern firework consists of a shell of plastic, papier-mache, or heavy paper surrounding compartments separated by cardboard. A small compartment at the base of the shell contains black powder to propel the firework into the sky from a mortar made of iron, aluminum, plastic, or heavy cardboard. A larger compartment contains chunks of a mixture of chemicals that produce light and color when heated. These chunks are known as stars. In American and European fireworks the stars are mixed with black powder inside a cylindrical compartment. The black powder explodes to ignite the stars and scatter them across the sky. In Asian fireworks the stars surround the black powder in a spherical compartment to produce a more symmetrical display. Instead of black powder and stars a compartment may contain flash powder, which produces a sudden bright light and loud bang. The various compartments in a firework are attached to fuses made of threads mixed with grains of gunpowder.
Black powder consists of a mixture of salt-peter (potassium nitrate), charcoal, and sulfur in a 75 to 15 to 10 ratio by weight. Flash powder consists of a mixture of potassium chlorate or potassium perchlorate, sulfur, and aluminum. Stars consist of a fuel that burns to provide heat, a coloring agent that provides color when heated, and an oxidizer to burn the fuel. Fuels may be slow-burning such as charcoal, dextrin (derived from corn starch), or red gum (a tree secretion) to produce a dim, long-lasting display, or fast-burning, such as aluminum, magnesium, or titanium, to produce a bright, short-lasting display. Sugar may be used as a fuel to produce smoke. Coloring agents include aluminum, magnesium, or titanium (white), carbon or iron (orange), sodium compounds (yellow), copper compounds (blue), strontium carbonate (red), and barium nitrate or barium chlorate (green). Oxidizers are highly reactive oxygen-containing compounds such as potassium perchlorate or ammonium perchlorate. They also contain chlorine, which reacts with the copper, strontium, and barium compounds in the
The most important quality control factor in making fireworks is safety. Firework factories are protected from intruders by chain-link fences, barbed wire, locked gates, steel doors, and tamper-proof locks. Within these factories, numerous precautions are taken to prevent accidents.
Electricity is the greatest danger. A single small spark can set off a roomful of explosives. All electrical outlets are located out-side the building. To avoid generating static electricity, all workers must wear 100% cotton clothing. They touch a copper plate before they enter a building to remove any static electricity they may be carrying. Elastic straps with wires trailing to the graphite floor are worn around the worker's calves, to drain static electricity away to grounding rods buried beneath the building. All work is halted and all workers leave the building if there is any possibility of an electrical storm approaching.
Many other safety measures are used. All work is done by hand, to avoid machines that could produce heat or sparks. In the winter, buildings are heated with hot water rather than hot air, which could cause an explosion. The buildings are small, so no one is more than one or two steps away from an exit. All exits have doors that open wide at the slightest touch. Explosive chemicals are never mixed when wet, because when they dry out they may release gases that could ignite them.
Brenner, Martha. Fireworks Tonight! Hastings House, 1986.
Plimpton, George. Fireworks. Doubleday, 1984.
Begley, Sharon. "Up in the Sky! It's…Hearts! Stars! Bow Ties!" Newsweek, July 9, 1990, p. 60.
Conkling, John A. "Pyrotechnics." Scientific American, July 1990, pp. 96-102.
Kozlou, Alex. "First Family of Fireworks." Discover, July 1990, pp. 40-45.
— Rose Secrest