[SML] SML Fireworks Basics

[Michael Powers]

Dave Vick is correct. Gunpowder, whether black powder, modern smokeless or Pyrodex, does not explode. They just “burn” exceedingly fast.  
While the difference may seem so small as to be meaningless, I assure you it is not!  Exploded or detonated propellant would result in gun barrels and launch tubes bursting at the breech while the intended projectile might travel only a “relatively” short distance and that at “relatively” slow speed.  Gunpowder works because it specifically does not explode but burns or deflagrates very very rapidly, producing a gas with many, many times the volume of the gunpowder.  Just as steam is a vapor a volume of a magnitude greater than the water creating it.  The pressure from the expanding gas pushes the shell/bullet out of the barrel with the pressure continuously building as the still burning propellant increases the pressure behind the projectile until it exits the barrel/launch tube.  You’ll remember from the cartoon what Elmer Fudd’s shotgun looked like after Bugs Bunny stuffed a carrot down the barrel before Elmer pulls the trigger.  The “blossom” effect you see is real (although it would probably take more than a carrot) as the pressure “slowly” builds to a critical point at which time the barrel bursts at the thinnest point, the muzzle.  If gun powder exploded or detonated we would not have fire arms or fireworks as we know them today.

Michael Powers
USMC '65-'69
ETCP Rigger #820 (Ret'd)

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