The Science of Fireworks – Get Ready for the Fourth!
Did you ever wonder how fireworks actually work?
The folks at How Stuff Works outline the process perfectly.
Just about everyone in the United States has some personal experience with fireworks, either from Fourth of July or New Years Eve celebrations. For example, you have probably seen both sparklers and firecrackers. It turns out that if you understand these twopyrotechnic devices, then you are well on your way to understanding aerial fireworks. The sparkler demonstrates how to get bright, sparkling light from a firework, and the firecracker shows how to create an explosion.
Firecrackers have been around for hundreds of years. They consist of either black powder (also known as gunpowder) or flash powder in a tight paper tube with a fuse to light the powder. Black powder contains charcoal, sulfur and potassium nitrate. A composition used in a firecracker might have aluminum instead of or in addition to charcoal in order to brighten the explosion.
An aerial firework is normally formed as a shell that consists of four parts:
- Container – Usually pasted paper and string formed into a cylinder
- Stars – Spheres, cubes or cylinders of a sparkler-like composition
- Bursting charge – Firecracker-like charge at the center of the shell
- Fuse – Provides a time delay so the shell explodes at the right altitude
Located just below the shell is a small cylinder that contains the lifting charge.
The shell is launched from a mortar. The mortar might be a short, steel pipe with a lifting charge of black powder that explodes in the pipe to launch the shell. When the lifting charge fires to launch the shell, it lights the shell’s fuse. The shell’s fuse burns while the shell rises to its correct altitude, and then ignites the bursting charge so it explodes.
Click here for the complete story on how fireworks work.