28 Feb 2010 03:26 UTCSun 28 Feb 2010 - 3:26 am UTC
Hypothetically speaking, if the flames of a fire could be black, would it be hotter than a blue or red flamed fire? I know this probably does not exist in physical life, but just by going off the principles of chemicals which cause fire, what would cause a fire flame to be black, and if so, would it be hotter than a blue or red flame?
28 Feb 2010 14:17 UTCSun 28 Feb 2010 - 2:17 pm UTC
Practically, it is difficult to produce a black flame but theoretically such a flame will exist if flame temperature is so low that it does not emit any visible color (see 1). Often, we observe black color on the outer edges of a candle flame or near the base. The blackish color on the edge is actually soot particles and residue produced from a yellow colored flame due to lack of oxygen around that particular area (see 2). You may also see black color at the inner most zone (base) of the candle flame. The black color is actually wax vapor which are not burnt due to lack of oxygen (see 3). Disregarding invisible radiation, flame temperature may be categorized as red, orange, yellow and white/blue (see 4, 5). Therefore, visible black wax vapors at the bottom of a flame or black soot particles around the edge of a yellow flame are not as hot as other flame colors.
For a simple illustration, see link 3, http://www.educationalelectronicsusa.com/c/fuels-VIII.htm