As the firework shoots through the air, the time-delay fuse continues to burn.
When the shell is close to its apex, the fuse has burned low enough to ignite
the black powder in the first break (or compartment). Colored
stars ignite in every direction. But the show isn't over yet. The fuse
keeps burning, making its way toward the stashes of black powder in the second
and third breaks.
Timing is critical. In a three-break firework, the middle break needs to
ignite at the highest point in the shell's trajectory—the first break should
blow a little before and the third break, a little after. If the timing is
off, the firework might detonate too close to the ground. Great care is used
in designing the fuses and calculating their lengths.
(back to Anatomy)
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