Candles and campfires have yellow flames, but you can also make yellow fire by changing the color of a blue flame. Here’s a look at the colors that produce golden or yellow fire. Both elements and compounds are discussed.
Elements That Make Yellow Fire
Some metal ions turn flames yellow. This is due to the emission spectrum of the ion. The flame test in chemistry uses this phenomenon to help identify the composition of a sample. Some of these metal ions are safe and common, while others might only be found in a lab:
- Sodium – Intense Yellow
- Cerium – Yellow
- Iron(II) – Gold
- Manganese(II) – Yellowish Green
- Molybdenum – Yellowish Green
- Vanadium – Yellowish Green
Of these, the most common elements used to make yellow fire are sodium and iron. Sodium produces such a bright yellow flame that trace amounts overpower the emission spectra from other elements. Small amounts of sodium account for the yellow color of campfires and candles, although the temperature of the flame also plays a part in its color. The yellow part of an ordinary fire tends to be around 1100 °C (2012 °F).
Safe Compounds That Make Yellow Flames
Common sodium compounds used to make yellow flames include:
- Table salt (sodium chloride or NaCl)
- Baking soda (sodium bicarbonate)
- Washing soda (sodium carbonate)
- Sodium nitrate – Also functions as an oxidizer
But, other elements in sodium compounds may alter the flame color. For example, sodium borate makes a green flame rather than a yellow flame because of boron. Still other sodium compounds produce a yellow flame, but aren’t used for safety reasons. For example, sodium hydroxide (NaOH) produces a yellow flame, but it’s caustic and can cause chemical burns.
Easy Yellow Fire Instructions
Many fuels produce yellow fire without any help. Alcohol, natural gas (methane), propane, and naphtha tend to burn blue, but are easily colored yellow.
While you can sprinkle yellow fire chemicals onto a flame, you’ll get a much better display if you dissolve them first. Salt, baking soda, washing soda, and sodium nitrate all dissolve in water, but you don’t want to extinguish your fire. Dissolving in rubbing alcohol (like 70% alcohol) works much better because it contains enough water to dissolve the compound, but alcohol to help the fire. Then, you can mix the dissolved salt with any liquid fuel. Alternatively, use a spray bottle to spritz a blue flame to turn it yellow. Do not pour alcohol (or any fuel) onto a burning fire.
Flick iron filings or any of the safe sodium compounds at the flame to see yellow sparks. Iron filings and powder find use in fireworks to make gold stars, while sodium tends to be avoided because it’s so overpowering.
Safety
As with any fire project, adult supervision is required. Any time you light a fire, have water or a fire extinguisher handy.
References
- Jarosinski, Jozef; Veyssiere, Bernard (2009). Combustion Phenomena: Selected Mechanisms of Flame Formation, Propagation and Extinction. CRC Press. ISBN 0-8493-8408-7.
- Melvill, Thomas (1756). “Observations on light and colours”. Essays and Observations, Physical and Literary. 2:12–90.
- Sanger, Michael J.; Phelps, Amy J.; Catherine Banks (2004). “Simple Flame Test Techniques Using Cotton Swabs”. Journal of Chemical Education. 81 (7): 969. doi:10.1021/ed081p969