Christmas is a kaleidoscope of sensations and stimuli, from advertisements to lottery prizes, including nougats, marzipans, red flowers, festivals of lights and… the fireplace with the wood burning.
The fire has something hypnotic, the flames rising, defying gravity, drawing a thousand and one different shapes. These light and heat whims are based on a chemical reaction that occurs when a combustible element (wood, coal, gasoline or flammable gas) comes into contact with oxygen and a heat source. When combustion occurs the result is light, heat and smoke.
There are four different types of flames: pre-mix, diffusion, bunsen and cold flames. Pre-mix flames are produced by joining gaseous fuels with air and oxygen; spreading flames are produced mainly by liquids and solids (candle flame); the bunsen flame is related to fuels of the hydrocarbon type and, finally, the cold flame is manifested when the molecules are broken down into simpler ones.
The flames of fire have molecules that move so fast that they raise the temperature and allow us to see lights of different colors, which vary depending on the fuel and the temperature, among other variables. In this way, the flames can be yellow, red, orange, blue, green or white.
The more red, the lower temperature
Although we usually represent red as a synonym for heat or danger, in fires it represents the coldest temperatures. When the flame is red and yellow, it indicates that the combustion is incomplete and, generally, the temperature does not exceed 1,000º C. In this type of flame, there is usually an oxygen deficit during combustion.
If the flame is blue, it means that the combustion is clean, that all the fuel has been burned and that its temperature is much higher (above 1,300 ºC).
In the event that the flame is orange in color, the temperature is between 1,000 and 1,200 ºC. Finally, the white flame is produced when the temperature oscillates between 1,300 and 1,500 ºC, and is characteristic, for example, of the Bunsen burner.
From this explanation it follows that the combustion flame of a gas stove should always be blue in color. If the flame were yellow or orange, it would mean that there is a fault in the mixture with the air and that poor combustion has been generated; if it were green, it would indicate that zinc, bronze or copper particles are burning, there being a failed combustion, and if it were red, it would mean that there are oxide particles burning.
Color shades of a candle
If we look at the flame of a candle we can see the different shades of fire. The part closest to the candle is usually white, since the temperature near the fuel source is the highest, and as we move further away, since there is less temperature, the color turns orange until reaching the tip where It’s red.
Finally, we are left with a curiosity, pyromancy (from the Greek pyro -related to fire-, and mancia -divination-) consists of guessing from the color, the snap or the disposition of a flame. Quite possibly it was one of the first forms of divination, there being evidence that it was already carried out in ancient Greece, where the virgins of the temple of Athena in Athens practiced it regularly.