If you’ve ever been to an aerial fireworks display at an amusement park, baseba-ll game, July Fourth celebration, or New Year’s Eve, then you know that fireworks all have their own unique and beautiful magic — a good show is completely breathtaking.
Only the most intricate fireworks display starts with a single crack, as black powder shoots mortar shell. The launch will set off a cascade of whooshes, zips, and bangs that will bring colorful shapes to the sky. Here’s how engineers will tweak these pyrotechnics to provide dazzling shows to the spectators.
Fireworks have followed the same basic format for centuries: As a fuse inside a sky-bound shell burns down, it ignites a series of explosive charges. Little pellets called “stars” sit in clusters between them and burst aflame as they fly out into the air.
“White fire” ruled the skies until the 1800s, when engineers first added metals and salts to their mixtures to create a rainbow of hues. Strontium (red), aluminum (white), and copper (blue) are common components.
Want your show to really pop? Tightly cramming chemicals into tubes makes a sharp whistle as gases squeeze out like steam from a kettle. Drilling tiny exhaust holes on the sides of a snugly sealed charge creates a delightful, buzzy hum as the apparatus spins.
Roughly everybody in the U.S. has some prior experience with fireworks, either from July Fourth or New Years Eve celebrations. You have also seen sparklers as well as firecrackers for example. If you understand these two pyrotechnic devices, it turns out that you’re well on your way to understanding aerial fireworks. The sparkler demonstrates how a firework can carry brilliant, sparkling light, and the firecracker demonstrates how to produce an explosion.
For hundreds of years firecrackers have been around here. They consist of either black powder (also known as gunpowder) or flash powder with a fuse to light the powder in a tight paper tube. Black powder, briefly discussed in How Rocket Engines Operate, has carbon, arsenic, and potassium nitrate in it. A formulation used in a firecracker can include aluminum to brighten the blast, instead of or in addition to charcoal.
Sparklers are very different from firecrackers. A sparkler burns over a long period of time (up to a minute) and produces extremely bright and showery light. Sparklers are often referred to as “snowball sparklers” because of the ball of sparks that surrounds the burning portion of the sparkler. A sparkler consists of several different compounds:
- A fuel
- An oxidizer
- Iron or steel powder
- A binder
Firework technology is still evolving. Many manufacturers of fireworks are now starting to use compressed air rather than gunpowder, which is considered healthier and allows for greater precision. Ongoing work aims to make the process more environmentally friendly through the use of different ingredients. Many firework chemicals, particularly the heavy metals used to create colors, may be carcinogenic or harmful to humans and animals when they are ingested into the soil, dispersed through the air, and dispersed over rivers. The central mechanism is exactly the same as it was in the 7th century.
But no, this doesn’t mean you have to try it at home.
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