Fireworks

            
             Fireworks makers fill the night sky with countless effects in displays that are popular all over the world. Although the art dates back to ancient China, most of the effects you'll see in a typical display are inventions from this century. A typical example is the development of colored flames. Before the 19th century, only various yellows and oranges could be produced with steel and charcoal. Chlorates, an invention of the late 18th century and an industrial product of the 19th century, added basic reds and greens to a pyro's range. Good blues and purples were not developed until this century, although it is not unusual to find unsafe display formulas for blue stars in earlier times.
             You have probably seen both sparklers and firecrackers some where or another. And if you understand these two basic pyrotechnic devices then you are well on your way to understanding aerial fireworks such as bottle rockets. Firecrackers have been around for hundreds of years and consist of either black powder (also known as gunpowder) or flash powder in a tight paper tube with a fuse to light the powder. Black powder, contains charcoal, sulfur, and potassium nitrate. A composition used in a firecracker might have aluminum instead of or in addition to charcoal in order to brighten the explosion. Sparklers contain four major components. A fuel comprised of charcoal, and sulfur, as in black powder. The binder can consist of sugar or starch. Mixed with water, these chemicals form a thick liquid compound that can be applied to a wire by dipping the wire into the compound. It can also be applied by pouring the compound into a tube with the wire already in the tube. Once the compound dries to the wire it is then a sparkler. As soon as lit. It burns from one end to the other, like a cigarette. The fuel and oxidizer are proportionated along the length of the wire so that it burns slowly rather than exploding much like a firecracker.