Have a blast this Fourth of July
By Staff
Staff Reports, Hartselle Enquirer
Fireworks displays have become a common component of celebrations worldwide. They mark grand openings of businesses, signify American independence on July 4th, light up boardwalks during the summer tourist season, and even commemorate birthdays and other special events.
While sitting awestruck watching a fantastic fireworks display, have you ever wondered the science behind those brilliant flashes of color and deafening "booms" in the night sky? If so, here's a brief description of the chemistry behind fireworks displays.
Brilliant Stars
Creating fireworks that display certain colors and patterns is intricate work requiring art expertise and knowledge of physical science. The three main components of firework "stars" (the points of light given off) are an oxygen producer, fuel binder (to keep the parts where they should be), and a color producer. In regard to color production, incandescence and luminescence are the key phrases to know behind the brilliant displays.
Incandescence is light formed by heat. Heat will cause a substance to get hot and eventually glow, giving off a specific color depending upon the substance. Substances initially burn at red, turn to orange, yellow, and eventually white light at extreme temperatures. Firework temperatures are carefully controlled to emit the right shade.
Luminescence is light that is formed from methods other than heat. According to About.com, to produce luminescence, energy is absorbed by an electron of an atom or molecule, causing it to become excited, but unstable. When the electron returns to a lower energy state the energy is released in the form of a photon (light). The energy of the photon determines its wavelength, or color. Additionally, other substances – salts – need to be mixed in to form desired colors. They may need to be balanced out with other components to make sure the firework will remain stable until it is lit.
To create colors, some components used in fireworks include copper, which produces a blue flame; strontium to make a red one; and burning charcoal to create golden sparks. The chemicals are mixed together and usually form into balls of different sizes that will form the stars when the firework is ignited.
Packaging It Up
Pyrotechnicians use different sizes and groups of stars and put them into a shell, the tube that holds the chemical balls, to make thousands of different effects. The stars may be mixed according to size and color and are usually packed in between rings of black powder explosive and charges. A fuse will be included to start the detonation. The entire shell is wrapped in brown paper and sealed.
At the scene of the fireworks display, the shells are placed in hollow tubes that are dug into sand or attached to another type of housing. Thousands of shells will be used depending upon the intricacy of the firework display.
The Finished Product
Today, most of the larger fireworks displays are controlled by a computer board that is programmed so the ignition of fuses is timed to musical clues from song accompaniment. This way fireworks will launch and explode at the right moments to create the ultimate drama.
Safety
It is important to note that professional fireworks displays are handled by pyrotechnicians who are skilled and knowledgeable of the science behind fireworks. Amateurs should never attempt to build homemade fireworks, which can be unstable and dangerous.
