A Colour Fire

Just a few days before, my friend had showing me a lighter that having a colour fire. This reminds me that, I had join a scout activity that they having a coloured camp fire. So I just wanted to know how to colour the fire. Coloured flames in camp fire are a way to bring some laughter. Coloured flames are also a great way to make people think you are a little magical.

What is the Theory behind the Colour Flames?
Behind the beautiful colour of the flames, there is a complex chemical process behind it. The process involves the Bohr Theory and jumping electrons. The Bohr Theory of the atom says that electrons occupy only one energy level at a time. Atoms with enough energy "jump" to higher, less stable, energy levels. When atoms lose energy they "fall" back to the lower, more stable energy levels. These two types of energy, "falling" and "jumping" are emitted though photon electromagnetic radiation. If the energy is visible light, then the colour of the light depends on if the atoms are "jumping" or "falling". These moving atoms are excited and produce specific lines in its spectrum. A flame test excites these atoms and knocks the ones residing in the higher, less stable levels down to lower energy levels, changing the colour of the flames. The wavelength (colour) of light that is given off is a characteristic of the elements present in the fuel and surrounding air. There is no one proper colour to fire, but since people tend to mainly burn carbon compounds in a mainly nitrogen atmosphere, there is an orange colour we are used to seeing and thinking of as the colour of fire.

Different Colour with Different Flame Colourant
If want to produce other colours, we just have to introduce other elements to the flame, so that they can give off their own characteristic colours.
Metal ions tend to provide the most dramatic colours.

Red - Strontium Chloride
Orange - Calcium Chloride (a bleaching powder)
Yellow - Sodium Chloride (table salt)or Sodium Carbonate
Green - Copper Sulfate
Blue - Copper Chloride
Violet - 3 parts Potassium Sulfate1 part Potassium Nitrate (saltpeter)
Purple - Potassium Chloride

How to Prepare Colour Fire?
The comment experiment is to place a little of the salt in a wire loop which is then held in the flame of a laboratory burner. Then this will generates the colour for observation, but requires continuous working and usually will only colour some parts of the flame.
The alternative method is to dissolve a little of the salt in ethanol in a non-flammable container. The mixture is then being light up. Alcohol flames produce very little visible light, so most of what you see is directly due to the metal.

Points to Keep in Mind
· The element sodium burns with the comment yellow flame. This element can overwhelm any other color. If you are making a dry mixture of colourants, you should avoid including any colourant that include sodium in it.
· If you are using alcohol-based colorants: Remember that alcohol is flammable. You should allow it to evaporate before use to avoid a lighter-fluid effect. Use with CARE!
· Don't colour BBQ fire! The colorants may produce pretty flames, and thus can also produce toxic food.
· Keep the colourants away from children. Handle them with the care and respect due to potentially hazardous chemicals. Read and follow to any warnings listed on product labels.