Chemistry of Fireworks at the University of Birmingham

IMG_1772I am just back from Birmingham after visiting the University of Birmingham to attend a Lecture organized by the Royal Society of Chemistry on the Topic “Chemistry of Fireworks”. I was the odd one out in the group from Rendcomb as all the other students who came took Chemistry as a subject. I decided to go because I am interested in anything which is science. I was informed of this Chemistry Trip by a fellow Student Olivia Ellis. Thanks Livi ! ūüôā

This is the room that we were in. It was huge and you can see about 50% of the room in this picture. The speaker was Dr. Tom Smith who has started a company which acts as a legal consultant for Firework displays and anything involving fireworks. He has set up displays for the Starting and the Ending Ceremonies of an Olympic Game and also for the 2011 New Year Celebrations at London.
The talk was also filled with live firework demonstrations.
I made some notes during the talk which I am expanding below.
Fireworks are Simple Compositions.
Oxidants + Fuel -> Products + Heat
 
Oxidants
The oxidants are substances like Potassium Nitrate, Potassium Perchlorate, Barium Nitrate, Ammonium Perchlorate, etc
Oxidants or Oxidisers are basically used to produce oxygen in order to support the combustion of the fuel. They are usually Perchlorates, Chlorates or Nitrates. But after some time on the internet, I have noticed that they may also be Chromates or Oxides. 
 
Fuel
The fuel consists of mostly Gunpowder which is a mixture of Sulphur, Charcoal and Potassium Nitrate.
The fuel allows the firework to combust and is based on Metal Powders or Gunpowder. I am not sure whether Liquid Fuels are used in Fireworks. But based on the experience of having burst several firecrackers during Diwali, I can say that I have never come across a firework with Liquid Fuel.
A firework can also include additional components for various functions. It can consist of Metals to produce sparks, Metal Salts to Produce Various Colours, Chlorine Donors to enhance the colours produced by the metal salts, Delay Agents to produce glitter type effects, Resins to bind the various components together and Flow Agents for manufacturing.
Colours
Metal salts are used to produce various colour effects.
Strontium Oxalate for Red
Barium Nitrate for Green
Sodium Aluminium Fluoride (Cryolite) for Yellow
Copper Oxide for Blue
Calcium Carbonate for Orange
 
The Demonstrations

The first demonstration was just blackpowder (Gunpowder) which was lighted. It produced a very small bang with some smoke. After that, He showed a video of two anvils placed on top of each other with gunpowder between them which was lighted. The anvil above the gunpowder flew to a height of about a 10 storey building. On a completely different note, Anvil Shooting is a sport with a good base of people who participate. Read this article to know more.

There were various other demonstrations of colours and delay agents and few special effects like producing sounds. This was achieved by restricting the flow of the gases produced in order to vibrate the particles and create the sound.

The article was written on October 01, 2014 (The day we visited Birmingham). But published on October 15, 2014

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