Inevitably, sometime in our life we’ve witnessed a fireworks spectacular, whether it be via TV screen watching fireworks go off for the 4th of July, or experiencing it firsthand. But have you ever wondered how fireworks work? When understanding how fireworks function there are a few key terms one must understand. The first is the definition of pyrotechnics. Pyrotechnics is the craft of making fireworks through the use of chemical materials susceptible to exothermic reactions (that is, the release of heat). As we know from our discussion last class, Thermochemistry follows chemicals as they react in conjunction with energy (heat) and pyrotechnics is simply one example of these types of reactions. Perhaps what one aligns most with our memory of fireworks are the pretty colors. The pyrotechnic colors are achieved primarily through two processes: luminescence (using energy sources other than heat) and incandescence (from heat). Incandecence goes hand-in-hand with Thermochemistry. The addition of heat causing the emission of infrared and then as its energy increases it transitions from red to orange to yellow, and then finally to white light at the pinnacle of its heat. Often times, fireworks contain aluminum, iron, steel, zinc or magnesium dust as agents in helping to provide control of the temperature of the fireworks (and thus, the coloring) for the light show. In this way, pyrotechnics is very intertwined with our knowledge of Thermochemistry.
The bright light, smoke, heat, and often times sound released during and after fireworks are signs of the chemical exothermic reactions taking place. It’s also interesting to note how the actual firecracker mechanism is built. You’ll notice in the diagram I’ve added to this post that the blue balls are listed as stars. They can come in many shapes and sizes and can be spaced in different formations, which then affects the shape that the firework projects in the sky.
Note: the above picture was borrowed from How Stuff Works, "How Fireworks Work" and can be viewed here.
1 comment:
Fairly thorough explanation, with most of the gaps regarding 'what's the connection to thermochemistry?' initially filled in. Remember to treat your audience like they know _nothing_, and to frame semi-complicated explanations as though you were walking them through a tour : literally explaining each step as you move through the explanation, leaving little-to-nothing to chance.
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