Guest Post - The Art of the Big Bang

Today is going to be the first of our guest posts in which someone other than me writes up the post about an interesting subject. It might turn out that Saturday's will become our annual guest strips but we'll just have to wait and see. Oh yeah, this firework picture is one that I took myself, and with no further ado I present Rachel's article:

Have you ever wondered how the fireworks launched during Independence Day celebrations are created? Fireworks contain flammable materials that make the light, sound, and color. The fuel (usually black powder, sulfur, and a metallic compound) produces extremely hot gases when they are lit. This propels the firework out of its launcher. The launcher, made of steel tubes, is about three times the length of the firework, but has the same diameter to create an air-tight seal around the firework. The fuse is lit by electrical wires, through which an electric current rushes that ignites the fuse. There are two secondary fuses that are lit by the main fuse that react to light the lift charge and the time-delay fuse. The time-delay fuse burns as the firework flies through the air and ignites the black powder at each break. The time-delay fuse is very important because timing is critical. Within the breaks, which are compartments within the shell, there are small pieces of a chosen metallic material, known as stars. These “stars” create the brilliant flashes of light and color that is seen in a firework display.

What makes the memorable colors in fireworks? Colors in fireworks are controlled by their content. Specific colors appear when certain metal compounds are used. Fireworks come in the following colors: violet (potassium), yellow (sodium), yellowish-red (calcium), green (copper), scarlet (strontium), red (lithium), white (aluminum), and dull blue (copper chloride). Pyrotechnics still have not created a bright blue to be used. A way to test these metals is the flame test. In this test, a glass or metal rod is dipped in the metal substance to be tested, and then placed in a flame. The color of the flame will change according to which metal substance is present.

This light and color is also a result of combustion reactions. Combustion reactions have certain needs in order to work. They need an oxidizer, fuel, and energy. An oxidizer uses oxygen to create combustion. One common oxidizer in fireworks is potassium perchlorate. The first reaction in a firework is the lighting of the main fuse. The shell is propelled out of the launcher from a build up of carbon dioxide gas. The last reaction in a firework is the intense heating of aluminum, magnesium, or titanium. The final result is a breath-taking explosion of color and enjoyment.

If you would like to learn even more about fireworks check out this NOVA site. And a special thanks to Rachel for providing our first guest post.