Science Questions

What is the composition of fire? Guillermo Davies Ore

Chris -  Fire looks like a solid thing but it’s not. It’s actually just vapour. When you heat something up to a high temperature it shoves out chemicals which are volatile and flammable. They mix with oxygen which is coming from the air around them. They combust so they react with the oxygen and they burn releasing heat. They also produce some degradation products or burning products from combustion. When you make that it glows. It’s incandescent and it gives out light at different wavelengths and different chemicals make different coloured lights. That’s why flames have different colours. Sodium’s very common and that makes flames an orange colour. If you have incomplete combustion. If you have some sooty particles in the smoke or the vapour they’ll glow orange as well. This is why you then see this orange pattern.

July 2008