Whatever you BURN turns BLACK - Why??

           Whatever you Burn, let it be a piece of Paper, wood,  plastic, cloth or even Human skin. The original colour disappears and it always turns to BLACK. And also the smoke is always Black. Why is this so?? What makes all these things turn BLACK? I will explain that to you. In short it because of CARBON. The reason is so simple but it took a couple of days for me to find the answer. The explanation follows.

          

            Any material turns into black only when it is set on fire. For a material to catch fire it must be COMBUSTIBLE ie. it must be a FUEL. It's not that only PETROL, DIESEL nd other petroleum products are FUELS. Any material which sacrifices itself for the combustion ( The process of fire) to take place is a FUEL. So every material which catches fire is a FUEL. I have already explained the process of combustion in my earlier post  Tank full of FUEL will never EXPLODE - Why??.

           Now, let us see what makes a material combustible. I found that every COMBUSTIBLE MATERIAL has CARBON in it expect for the ECO - FRIENDLY fuels which don't have CARBON in them like HYDROGEN fuel. Carbon may not be in its original form, but it is however present in the material in other forms like HYDROCARBON in petroleum products and in the form of CELLULOSE in paper, wood etc. 

           By now you would have guessed the reason. It's because of CARBON and the colour of carbon is BLACK. The colour of COAL is BLACK because it has high content of CARBON. The explanation is not yet over. The secret is that the colour of the material, for example WOOD doesn't change to BLACK colour. But, it gets covered with Carbon particles which is BLACK in colour. If you take a half burnt wood and swipe it with your fingers. The black colour ( carbon particles) sticks to your hand and the original colour of the wood comes back. If the  wood is burnt completely only the unburnt BLACK Carbon particles fall behind.

         You may ask that, Carbon is responsible for the fire to take place then how does it stay behind? The answer is here, Carbon particles will not be left behind if the combustion is COMPLETE. The combustion process depends upon a number of factors like the air -fuel ratio, quality of fuel and so on. So its hard for a complete combustion to take place. You can't see black smoke coming out of an air plane because the fuel used is very pure. 

        So when you burn a piece of cloth or a wood, the wood doesn't burn completely and few carbon particles which are present in the wood are left behind which covers the wood and makes the wood to appear BLACK in colour. This is also the reason why the SILENCER of a vehicle turns black, the bottom of a vessel turning black ( when heated by burning wood) and many others.

         Few more things you should know:

• The WHITE ash which you see is a by-product of combustion, which is because of the presence of impurities like vanadium.

• The SMOKE is WHITE if the combustion is good.

• The BLACK smoke is because of the CARBON PARTICLES carried away by the smoke.