Each year, American’s spend the Fourth of July enjoying cookouts, pool parties, and parades celebrating our country’s independence. The day of celebration traditionally ends with fireworks! Do you know the science and engineering behind fireworks? Whether it’s sparklers in your backyard or a professional firework show, there are hundreds of hours of chemistry, physics, ballistics, and engineering behind these celebratory explosions! We did a little research into all the firework magic to break it down for you, step-by-step and special effect-by-effect.
UNDERSTANDING THE EXPLOSION
At the base of each firework is a long wooden or plastic stick known as the tail. This tail has two important functions. First, the tail helps detonators aim the firework to determine which direction the firework will go. The second ensures the firework flies high into the sky before it explodes.
Above the tail is a fuse, connected to a shell, containing all the magic you see exploding in the sky. The size and strength of the shell determines the size and strength of the blast. Each colored and glittering tendril soaring across the sky after a blast is the result of individual seeds perfectly positioned inside the shell. The varying shapes, sizes, and positions of these seeds result in different firework types.
SPECIAL EFFECTS + COLORS
The most outstanding feature of any firework show are the special effects and colors. A glittering effect is created by stacking the shells on top of one another within a cylindrical tube. When lit, these flicker and create the glittering feathered effect audiences love so much.
Animated fireworks, which begin as one color and end as another, are created by strategic placement of the seeds within the shell. An inner ring is created with one color seed, surrounded by an outer ring of another color. The inner ring is detonated first, starting the firework off as one color and then the second ring detonates and the explosion ends in a second color.
Fireworks colors are created with specific chemical combinations. A calcium salt formula bursts into a red-orange display because calcium has lower energy and a longer wavelength of light at the red end of the spectrum. A barium compound, with higher energy, results in an emerald color burst.