Why is fire orange?

Question

Why is fire orange?

Answer 1

red is the color of the heat particles I don't know.

Answer 2

Thank you Mz H; finally a hint at the truth!  Normal fire as we know it is NOT orange because of "reflection" of color, or really because of the chemical composition.  The orange you see is blackbody radiation.  Blackbody radiation is the color that ANY solid (made of any chemical) glows when it is heated to a certain temperature.  Around the temperature of fire, that color is mainly orange, but the peak color moves across the spectrum with heat from dark red to orange to yellow, white, then bluish white.  Anything glowing bluish white from blackbody radiation will blind you if you look at it--such as arc welding and the sun.    Blackbody radiation in a flame is caused by small carbon particles (solids) in a sooty flame.  If you eliminate the soot by making a complete burn (add more oxygen before burning like in a torch), then you eliminate the soot and you stop the blackbody radiation.  Now the color of the flame is dependent on the material making it.  In hydrocarbon flames, the color is blue.

The blue color you see in a flame has NOTHING to do with blackbody radiation and therefore NOTHING to do with temperature.  It has to do with the color of excited atoms of the types in a hydrocarbon flame.  Hydrogen flames are red, sodium flames are yellow, etc.  But any material that creates a sooty flames with solid smoke particles in it will have an orange (or temperature-dependent blackbody color) colored flame.

Anyone who says that the blue at the bottom of a candle flame is the hottest part of the flame has not actually spent the time to measure the temperature of this.  It's a complete urban myth propogated by the confusion that hot blackbody radiation is "bluish".  But the blue at the bottom of a candle flame is just the oxygenated part of the flame that has no soot and is just plasma excitation blue, not blackbody blue.  How do you test this hypothesis?  Stick a very small wire in a candle flame.  The wire will glow at the blackbody temperature.  in the  middle of the candle flame, the wire will glow bright orange, the same color as the candle.  Stick it in the blue part at the very bottom and the flame glows a dark red.  That's because it's cooler there.  If it were hotter, the wire would glow bright whitish blue and blind you (and melt instantly).  Seriously, try it and break the myth!

Edit:  Fizixx below is talking about the process that makes different colors of flames for different material.  That is correct for clean flames, but it is different than the blackbody radiation in "orange" flames that we see everyday.  If you look at the spectrum of a clean flame, you will see spectral line emissions specific to certain elements and compounds.  If you look at the spectrum of a normal "orange" flame, you will see a continuous band of color from red to blue with the peak around orange.

Answer 3

Its because of the heating of unburnbed carbon particles.

Answer 4

it is not the fire but the perceptive tools of your eye which are corns have got medullary tract which approaches to the left cerebral sphere & u view orange color ,so the credit 4 orange colour is due to carbon or i should betterly say hydrocarbons which so far you have seen on rusting iron & to judge the specific color is just coz of eye pigments

Answer 5

Fire can appear orange because that is the color of light spectrum that it is reflecting back into our eyes. The color of the flame depends on the gas that is being burned, any other material that is being burned, and the temperature.

Generally speaking, however, a flame will move through the color spectrum starting at blue or white (where it is hottest), and then transition to yellow, orange, and then red (where it is the coolest).

Answer 6

It is giving off high frequency light.

Answer 7

because blue was already taken by the sky.

Answer 8

The one thing no one has pointed out yet is that in the reactions going on in the flames are atoms excited in a manner whereby, electrons in an elevated state, decay back to a ground-state emitting photons at a wavelength consistent with the color you see, whatever color it happens to be.

This is what is actually giving the flame its color, regardless of anything else that people are submitting here whether it be true or untrue.

It gets irritating when people talk about everything else except directly answering a question. We elect our idiotic politicians who do this very same thing.

Answer 9

because its hot

Answer 10

Not all fire is orange.  The colour of fire depends on the temperature and fuel.  When you look at a flame burning on a candle, the central part is blue.  This is the hottest part of the flame.  The outermost part of the flame is red.  Fire is just a very hot gas, and when gas is excited, it gives off radiation in various wavelengths.  Visible light is what you see (white being the hottest, then blue, yellow, orange and red being the coolest).  Infrared is what you feel as heat.

Different materials burn with different colours, as well.  For example, copper chloride burns green, strontium chloride burns red, etc.  Oxygen level influences the colour of the flame.  Higher oxygen level results in bluer flames.  Floating particles of soot in the flame glow orange giving it a more orange colour.

Answer 11

red or orange because the fire is trapping the oxygen...