Re: What makes blue flames blue?
- In a nutshell the blue flame is an energy drop fromt he yellow
flame, not an energy increase-
Here's how my chemist friend explains the color difference:
The yellow-orange emission is nearly true black-body, note that a
flame casts a shadow if light is shined on it, but fortunately the
blue is way too thin to be a true black-body. If it were, the
radiation power of the blue part would be (600/400)^4, or 5 times
that of the yellow flame; candles would be really dangerous! The
reactions producing blue light must have electrons dropping about 3
volts, about right for a carbon-to-hydrogen bond to oxygen-to-
hydrogen bond energy drop.
--- In email@example.com, "meed7" <meed7@y...> wrote:
> I have always understood that the yellow flames seen above
> wood fires, etc is due to incandescent particles heated by the
> flame to the point where they emit yellow light... I guess to put
> number on it this, the temperature would be somewhere in the 1000-
> 2000 C range.
> But what makes the blue flame, seen for example on a gas stove and
> also at some places and times in a wood stove, blue? Since the
> temperature for "blue-hot" on the blackbody scale is well beyond
> 10,000 C, I don't think I'm seeing light emitted by incandescence
> (otherwise we'd have to wear welding goggles to look into our
> Is the blue that we see the characteristic wavelength of, say,
> oxygen combustion, or perhaps hydrogen-oxygen combustion? Anyone
> I have an inquisitive 9-year-old who has been asking these kinds
> of "why is the sky blue" type questions... and of course, to
> appropriately simplify the answer, one has to know much more than
> just the answer!