Fireworks

It is common for fireworks to contain aluminum, iron, steel, zinc or magnesium dust in order to create bright sparks. The metal flakes heat up until they become incandescent and shine brightly. Sometimes actually burn up.
             Now to learn about aerial fireworks since you now know the basics of pyrotechnics. An aerial firework is normally formed as a shell that consists of four parts: .
             áP Container - Usually pasted paper and string formed into a cylinder .
             áP Stars - Spheres, cubes or cylinders of a sparkler-like composition .
             áP Bursting charge - Firecracker-like charge at the center of the shell .
             áP Fuse - Provides a time delay so the shell explodes at the right altitude .
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             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 bursting 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 contents of the shell so it explodes. .
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             Simple shells consist of a paper tube filled with stars and black powder. Stars come in all shapes and sizes (several of the links below list dozens of recipes for different types of stars), but you can imagine a simple star as something like sparkler compound formed into a ball the size of a pea or a dime. The stars are poured into the tube and then surrounded by black powder. When the fuse burns into the shell, it ignites the black powder, causing the shell to explode. The explosion ignites the outside of the stars, which begin to burn with bright showers of sparks. Since the explosion throws the stars in all directions, you get the huge sphere of sparkling light that is so familiar at fireworks displays. The colors of aerial fireworks come invariably from stars, small pellets of firework composition which contain all the necessary ingredients for generating colored light or other special effects.