Colourful Campfires

Everyone knows that you get yellow fire from burning wood, depending on what you add to a fire you can change the colour of its flame. The reason particular colours are given out is due to the energy level the ‘burning’ happens at. Remember the old period table? (or if you had modern enough science teacher; a periodic galaxy?) well its all down its arrangement.

The Sciencey Bit

(Skip this if you really don’t want to know why) The reason different compounds or elements produce different colours when burnt is the oxygen combines with them changing the arrangement of the atoms electrons.

Electrons form orbits or ‘shells’ with higher levels of potential energy for each one in each each orbit, filling up the bottom orbits first. When an electron is exchanged from one shell to another light (photons) must be emitted with an energy matching the change in ‘height’ (potential energy) to maintain balance. The energy of a photon is determined by the Planck constant multiplied by its frequency (E = h×?) which means that different energies result in different frequencies some of which can be seen as a colour.

The Example Bit

The most readily known examples of coloured fire are interstellar stars, although in all honesty they’re not really balls of fire but energy releasing spheres of luminous plasma. Anyway, they come in a variety of different colours depending on there temperature which is based on there dominant fuel, in the The Sun’s case it is 75% Hydrogen and 24% Helium giving it a yellow colour from our atmosphere. As the Sun ages the Hydrogen will become Helium through fusion and it will appear red, just like the the Sun Krypton orbits in Superman and it is called what is known as a Red Dwarf. As the Helium ‘burns’ together into even denser materials it will eventually change to White Dwarf.

Another example that is slightly more down to Earth is the use of different compounds for stunning sky bound effects called fireworks. To produce the most brilliant colours other elements are used to enhance the colour produced from burning, usually Chlorine, which is toxic in large amounts.

The Safety Bit

WARNING: I wouldn’t suggest acquiring any of these elements and trying it out for yourself, especially since some of these substances alone are radioactive, toxic or both! This is intended as a reverse lookup; you see the colour then work out what made it. I’ve not listed every substance just the ones I could find any information on.

The Referencey Bit

Name Metal Image Flame Notes
Li   3
Alkaili Lithium suspended in Oil in Test tube by BioNerd Red to White Lithium Flame by Metal Chem White Fume
Sr   38
Alkaline Earth Strontium in Radiation Container by BioNerd Red, Crimson Strontium Flame by V31S70 Violent Reaction in Moisture, White Fume
Ca   20
Alkaline Earth Calcium in Test tube by BioNerd Brick Red, Orange Calcium Flame by Metal Chem  
Fe   26
Transition Iron (filings) in Test tube by daynoir Gold Easily Magnetic, Symbol from the Word ‘Ferrum’
Na   11
Alkali Silvery White Yellow Sodium Flame by Metal Chem Easily Cut with Knife, Reactive with Water, White Fume
Mn   25
Transition Silvery Metallic Yellowish green Poisonous, esp. if inhaled
Mo   42
Transition Grey Metallic Yellowish green May have facilitated multicellular lifeforms
Ba   56
Alkali Earth Barium in Radiation Container by BioNerd Pale/Apple Green Barium Flame by Metal Chem Mades rare Gem Benitoite
B   5
Metalloids (Deep) Brown Bright green Used in Scientific Glassware
Tl   81
Poor Silvery White Pure green Highly Toxic
Sb   51
Metalloids Antimony in Test tube by BioNerd Pale green antimony Flame by Metal Chem  
Te   52
Metalloids Lustrous Silver Pale Green  
P   15
Non Dull Red with White Sheen Pale bluish green Reactive when Cut, therefore used in Matches
Zn   30
Transition Zinc in Test tube by BioNerd Bluish Green Zinc Flame by Randeeryan White Fume
As   33
Metalloids Arsenic in Test tube by BioNerd Blue Extremely poisonous
Bi   83
Poor Bismuth in Test tube by BioNerd Blue Slightly Radioactive, Very Low Toxicity, Yellow Fume
Cs   55
Alkaili Caesium in Radiation Container by BioNerd Blue Slightly Radioactive
Cu   29
Transition Copper in Test tube by BioNerd Blue Copper Flame by Randeeryan Black Fume
In   49
Poor Light Grey Blue Used in Liquid Crystal Displays, Toxic
Pb   82
Post-transition Lead suspended in Oil in Test tube by BioNerd Blue High Density, Toxic, Stops Xrays Easily
Se   34
Non Dark Grey with metallic sheen Azure blue Key Ingredient in Head’n’Shoulders, MacGuffin in Evolution
K   19
Alkali Metal Silvery White Purple Potassium Flame by everyones idle Highly Reactive with Water
Rb   37
Alkali Grey White Red-violet Rubidium Flame by Metal Chem Highly Reactive with Water OR air
Al   13
Poor Aluminium in Test tube by BioNerd White Common Use, Very High Strength:Weight Ratio
Mg   12
Alkaline Earth Magnesium in Test tube by BioNerd White Magnesium Flame by I. Gelgard White Fume
Ti   22
Transition Titanium in Test tube by BioNerd White Food Colourant E171 (Titanium Dioxide)

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