Fireworks are combinations of gunpowder and other ingredients that explode with loud noises and colorful sparks and flames when they burn. Fireworks are also called pyrotechnics. Fireworks that only make a loud noise are called firecrackers. Fireworks are dangerous because they contain gunpowder. They should be handled only by experts. Fireworks handled improperly can explode and cause serious injury to the untrained user. Many states prohibit the use of fireworks by the general public. The federal government limits the explosive power of fireworks for nonprofessional users.
Most fireworks are made by packing gunpowder in hollow paper tubes. A coarse gunpowder tightly packed is used to propel (drive) rockets into the air. A finer and more loosely packed gunpowder explodes the rocket once it is in the air. See Gunpowder.
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Manufacturers add small amounts of special chemicals to the gunpowder to create colors. They add sodium compounds to produce yellow, strontium compounds for red, and copper and barium compounds for blue and green. Charcoal is another substance that can be added. It gives the rocket a sparkling, flaming tail.
How fireworks work.
Fireworks rockets, also called skyrockets, operate on a principle close to that used in large military rockets. A fuse, which may be made of rolled paper soaked with saltpeter, ignites the coarse gunpowder charge, forming gases that stream out of the end of the paper tube. This propels the rocket into the air. When the rocket is near its highest point of flight, the coarse gunpowder ignites the finer charge, and the finer charge explodes. The explosion breaks up the rocket and ignites many small firecrackers in the nose (forward section) of the rocket.
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Roman candles have gunpowder charges separated by inactive material. They shoot out a series of separate groups of sparks and flaming projectiles, which often explode with booming noises. Flowers have many small bursting charges that send out petals and threadlike pistils of different colors. Lances are paper tubes filled with color-producing fireworks. They are arranged on a wooden frame so that when set afire they outline a scene, a portrait, or a flag.
Other uses of fireworks.
Fireworks also have serious uses. A device called a fusee burns with a bright red flame and is used as a danger signal on highways and railroads. Railroads use giant firecrackers called torpedoes. The torpedoes explode while the train is passing over them to warn the engineer of danger ahead.
People can signal for help by using a Very pistol. The pistol shoots a flare into the air that can be seen far away. Parachute flares are used to light up landing areas. A kind of fireworks rocket shoots lifelines to shipwrecks. Another kind has been used to scatter silver iodide in clouds to produce rain. Star shells are used in wartime to light up battlefields.
See also Explosive; Independence Day.
