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Q & A: experiments on fire color

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Most recent answer: 10/22/2007
Q:
I know that fire can be made to change colors using different materials, but are there any easily obtainable materials that can change a fire’s color such as salt which was mentioned in another question?
- Jonathan
Holmdel High School,
A:
I should know this but don't, so I'll recommend experiments. If you have some nice safe controlled fire in a well-ventilated area (maybe in an outdoor grill) you can try sprinkling different materials on it to see what colors you get. The sodium in table salt ought to give a nice bright yellow. Maybe you could try potassium from potassium chloride, a salt sold for use by people who need to keep their blood pressure low. You might try filing down some copper wire, and see what colors you get from the copper filings. You could do the same with other standard metals that aren't very toxic, like iron or nickel or silver. Don't try it with lead, because you don't want extra lead fumes around.

There's a nice story about the chemist R. W. Wood. He was staying in a boarding house, which he suspected was recycling leftovers off boarders plates into the next day's hash. So he tried sprinkling some lithium salt on the leftover food on his plate. Lithium, if I remember right, gives off a distinctive bright red color. Sure enough, holding a match to the hash the next day gave a nice lithium glow. I'm not sure how easy it is to get lithium salts, such as lithium chloride. Don't swipe them out of the medicine cabinet, because someone may need them to maintain mental equilibrium.

Mike W.

(published on 10/22/2007)

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