Light Touch
Why Are Candle Flames Yellow?
Stephen Wilk says the answer to this question is much more complex than he thought.
[iStock / Ivan Bliznetsov]
Many of the sources I read for my recent column on luminous intensity (OPN, March 2016, p. 20) state that light from spermaceti candles and Argand oil lamps is brighter than light from ordinary paraffin or beeswax candles, which tend to give off a more yellowish glow. Although the formats are different, all of these old-fashioned light sources generate a flame from burning hydrocarbons. Since the fuel is the same, shouldn’t they all burn at the same temperature, color and brightness? Why are some flames brighter and whiter than others?
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