In Your Element! The Chemistry of Fireworks
The art of using mixtures of chemicals to produce explosives is an ancient one to say the least. Black powder - a mixture of potassium nitrate, charcoal, and sulfur - was being used in China well before 1000 AD and is also used in military explosives, construction blasting and, of course, fireworks. Years and years ago fireworks just used to be basically rockets and loud bangs and the colours such as orange and yellow came from charcoal and iron fillings. However, great advances in chemistry in the 19th century had new compounds finding their way into fireworks. Salts of copper, strontium, and barium added some brilliant colours. Magnesium and aluminum metals gave a dazzling white light. So, how do fireworks actually produce these brilliant colours and rather loud bangs? Well, it’s all thanks to nature’s elements and chemistry. There are really only a handful of different chemicals that are actually responsible for the most spectacular effects. To produce the noise and flashes, an oxidizer, (something that has a strong affinity for electrons) is reacted with a metal such as magnesium or aluminum mixed with sulfur. The resulting reaction produces a brilliant flash, which is due to the magnesium and aluminum burning, and the rapidly expanding gases produce a loud bang.
For a colour effect, an element with a coloured flame is included. Yellow colours in fireworks are due to sodium, strontium salts give the red colour and barium salts give the green colour. Achieving the vivid white flashes and the brilliant colours requires complex combinations of chemicals. For example, because a white flash produces high flame temperatures, the colours tend to wash out. Another problem arises from the use of sodium salts. Because sodium produces an extremely bright yellow colour, sodium salts cannot be used when other colours are desired, (It would be worth checking out the energy states of atoms that goes into more detail about the colours that elements give off during different energy levels).
In short, the manufacturing of fireworks that produce these desired effects requires a very careful selection of chemicals. People have even written books on the subject; there is an entire plethora available. No wonder fireworks cost so much!
~ JM
Image Credit: http://bit.ly/1zaRnEs
More Info: Check out this very informative short video explaining the chemistry in more detail: The Chemistry of Fireworks – Reactions:http://bit.ly/1pEedlY
Atomic Spectra - Interactive: http://bit.ly/1FVECSa
Flame Coloration by Element: http://bit.ly/1Cch6i0
