Students learn about how to make a firework by discovering the requirements of combustion, how to enhance combustion using an oxygen supply, how to adjust the colour of the fireworks, how sparklers are made & how rockets work.
The project runs for one term. Each session can continue over more than a week as necessary.
Students compared the combustion of a variety of fuels for ease of ignition, ease of storage and suitability for use in a firework. Students learnt that none of the fuels they burnt were really suitable because they were either too difficult to ignite or were liquids.
Students also discussed the requirements of combustion (fire triangle) and watched a demo of the Screaming Jelly Baby, which introduced the use of a chemical (Potassium Chlorate) to provide oxygen to the fuel.
Students discovered how to add various colours to a firework by completing flame tests on a variety of metal salts. Students consolodated this work by predicting the flame colours of exploded hydrogen balloons sprayed inside with a salt solution, and by using a pump-action spray bottle containing a salt dissolved in ethanol which was sprayed over a lit bunsen. Doing these tests in a darkened room really enhances the appearence of the colours. Finally students watched a commercial firework rocket launch and correctly identified the metals in the salts used to create the various colours.
Students investigated how sparklers are made. They tested various powdered metals to see which produced the best sparks and varied the addition of metal salts to add some colour following what they learnt during the last session.
Students then compared their homemade sparklers with the commercial ones available, linking their knowledge of the use of potasium chlorate (or nitrate) as an oxidisng agent.
Session 4 & 5:
Students made some Chinese Lanterns.
They built the lanterns from biodegradeable material (having sprayed them with a flame retardant), tested their ability to produce lift (a good point to discuss the physics) and then flew them after dusk on a windless evening (remember to obtain permission to fly them from your Headteacher, and to have some commercially produced lanterns for comparison).