Some of you may have been fortunate enough to enjoy the fabulous array of fireworks Sunday night at the grand finale of GlobalFest 2013. But have you ever stopped and stared at those pretty lights in the sky and wondered how these fireworks actually work?
I am not just talking about the meager firecrackers or the ever-so traditional sparklers that we see at almost every birthday party. The fireworks that I am referring to are the pyrotechnics of the aerial sort; the ones that grace us with their emphatic presence and leave us all with our jaws gaping down to our knees. Any type of fireworks have the same foundation. Gunpowder, most often including potassium nitrate or any other type of oxidizer, is employed to create the explosion or the much acclaimed “bang” upon ignition. The vibrant colors that we see are the cause of inflamed metal salts. These compositions may include, aluminum, zinc, magnesium, iron, or zinc. This method also creates the ‘sparkling effect’ that is displayed.
Check out this cool video of the burning of different metals/elements to create different colours.
What makes aerial fireworks unique from the structures of fire crackers, sparklers, etc. is that they have an exterior shell. Four elements conform this shell: a container, stars (like the ones you see on sparklers), a bursting charge (similar to the source in a firecracker), and a fuse. For a more detailed description on each of these individual segments, check out http://science.howstuffworks.com/innovation/everyday-innovations/fireworks1.htm. This shell is then projected into the air by a mortar that contains a lifting charge. Even though the shell may be ignited, it is delayed from lighting up fully due to the fuse in the shell that allows the firework to explode at just the right altitude. Besides the rudimentary workings of the shell, there are different types of shells as well. For example, a simple shell may just be a single tube filled with a multitude of stars. The exterior of these stars will burn once the shell explodes. This causes the wonder wheel of light that we commonly see. Multibreak shells break in several phases. This simply allows for more controls on the visual effects of the fireworks (i.e. brightness, color, etc.).
In order to construct the various patterns of the fireworks in the sky, the ratio of stars and their organization within the shellhas to be contemplated accordingly. To see the assortment of the diverse types of multibreak shells and how they appear in the night sky, go to http://science.howstuffworks.com/innovation/everyday-innovations/fireworks2.htm.
From the composition used to establish the exuberant colors and brightness to the wondrous shapes of the fireworks, the workings of fireworks are clearly a ‘banging’ performance in and out of itself.
Other featured links include: http://www.planet-science.com/categories/over-11s/technology/2011/11/how-do-fireworks-work.aspx