From firecrackers and sparklers to the ear-shattering Excalibur mortars, celebrating Independence Day with fireworks is a tradition dating to 1776. More recently, shell-making has become more sophisticated with shells that explode into patterns, and pyrotechnicians use computers and remote firing systems to synchronize the firing of shells with a musical score.
The city of Greenfield will launch its fireworks show beginning at dusk Friday at Greenfield Central Junior High School. The Fortville fireworks show will begin at dusk Saturday in Landmark Park.
Circle City Pyrotechnics organizer Donnie Eicks said the Greenfield show will last about 25 to 30 minutes, and will be new for anyone who has seen the show in the past.
Spectators can expect to see images in the sky including fish, bow ties, hearts, smiley faces and more.
Understanding how fireworks work
If you understand sparklers and firecrackers, then you are well on your way to understanding aerial fireworks. The sparkler demonstrates how to get bright, sparkling light, and the firecracker shows an explosion. Firecrackers consist of either black or flash powder in a paper tube with a fuse. Black powder contains charcoal, sulfur and potassium nitrate, but aluminum may be added to brighten the explosion. Sparklers burn for a long period of time and produce extremely bright and showery light. The fuel is charcoal and sulfur – as in black powder.
The binder can be sugar or starch. Once mixed with water, these chemicals form a slurry
that coats the wire or is poured into a tube.
Simple shells consist of a paper tube filled with “stars” and black powder. Stars come in all shapes and sizes, but you can imagine a simple star as something like sparkler compound formed into a ball the size of a dime.
The stars are poured into the tube and surrounded by black powder. When the fuse burns into the shell, it ignites the bursting charge, causing the shell to explode. The explosion ignites the outside of the stars, which begin to burn with bright showers of sparks. The explosion throws the stars in all directions producing a huge sphere of sparkling light.
Multibreak Shells burst in two or three phases. They may contain diverse stars to create any kind of display. Some shells contain explosives designed to crackle or whistle as well.
Multibreak shells can also be filled with other shells, or multiple sections. The bursting of one section ignites the next. The shells must be assembled in such a way that each section explodes in sequence to produce a distinct separate effect. The explosives that break the sections apart are called break charges.
The pattern that an aerial shell sprays in the sky depends on the arrangement of star pellets inside the shell. To create a smiley face in the sky, an outline of star pellets is created and surrounded with a layer of break charge. Explosive charges are set inside those pellets to blow them outward into a large figure. Each charge has to be ignited at exactly the right time for the image to appear.
Round shell: Explodes in a spherical shape, usually of colored stars
Willow: Contains long-burning stars that fall in the shape of willow branches and may even stay visible until they hit the ground
Roundel: Bursts into a circle of shells that explode in sequence
Serpentine: Bursts to send small tubes of incendiaries skittering outward in random paths
It’s common for fireworks to contain aluminum, iron, steel, zinc or magnesium dust in order to create bright, shimmering sparks. The metal flakes heat up until they are incandescent and shine brightly or – at a high enough temperature – burn. A variety of chemicals can be added to create colors.
White: Magnesium or aluminum powder
Red: Strontium compounds
Orange: Charcoal or iron
Yellow: Sodium compounds
Green: Barium compounds
Blue: Copper compounds
The Indiana Department of Homeland Security recommends the following firework tips.
• Never let children handle, play with or light any fireworks without adult supervision.
• Store fireworks in a cool, dry place away from children.
• Use a clear, open area and keep the audience a safe distance from the shooting site.
• Do not attempt to make or alter any fireworks.
• Only purchase and light 1.4G consumer fireworks. Examples include bottle rockets, roman candles and firecrackers.
• Only light one firework item at a time and never attempt to re-light or fix a “dud” firework.
• Have a fire extinguisher, water supply, hose or bucket of water nearby.
• Use extreme caution when lighting fireworks in the wind. Keep spectators where the wind is blowing away from them.
• Never smoke or drink alcoholic beverages while handling fireworks.
• Never aim, point, or throw fireworks at another person.
SOURCES: American University, Washington, D.C., Indiana Department of Homeland Security, History.com, HowStuffWorks.com