Science Fair Time Again

Monday, March 9, 2009

Isabella likes colors. And fire. So she wanted to make colored fire. We tried a lot of different techniques, some we found on the interwebs and some we made up to make colored flames from various chemicals we got from United Nuclear.

DSC_0835_Sm.jpg

We tried my childhood Bunsen burner with straight ethanol which didn’t work out so well. Contaminating the wick with chemicals was effective, but not in distinguishing between sample chemicals.

DSC_0860_Sm.jpg

Then we tried soaking the a pile of the chemical under test in ethanol and setting it on fire in a watch glass, which was a lot of fun, but didn’t do so well in the distinguishable colors dimension and a bit of a pain in the ass to clean the watch glass between samples.

DSC_0844_Sm.jpg

We tried using a 316L 3/16″ welding rod hammered into a shallow spoon as a chemical scoop (one for each chemical) and holding it the flame of a propane torch. This worked pretty well but some chemicals (copper oxide for example) didn’t really do much until the rod was white hot, and even then there wasn’t too much color. Others (lithium carbonate) worked really well.

DSC_0894_Sm.jpg

We got some Nichrome wire from McMaster and made an electric loop. We dipped the wire in clean water and then in the chemical under test (Lithium carbonate first) and then ran about 8-9A through the wire until it was white hot. It looked promising, but then the wire melted and burned through.

DSC_0851_Sm.jpg
Iron Filings

So we used little loops of the NiChrome wire to hold samples in the propane flame. The 0.020″ wire heated a lot faster than 3/16″ welding rod and the results were more satisfactory, though Barium Carbonate was yellow orange, not green as expected.

DSC_0910_Barium_Carbonate_Sm.jpg

Barium Carbonate

DSC_0912_Calcium_Carbonate_Sm.jpg

Calcium Carbonate

DSC_0915_Copper_Oxide_Sm.jpg

Copper Oxide

DSC_0917_Cryolite_Sm.jpg

Cryolite (Sodium) [not a lot of differentiation between yellows]

DSC_0921_Lithium_Carbonate_Sm.jpg

Lithium Carbonate

DSC_0926_Zinc_Sm.jpg

Zinc dust

The best assortment we tested would be Cryolite, Lithium Carbonate, Zinc, & Copper Oxide which yield a bright, easy to reproduce, and clearly differentiated spectrum of colors.

Next we build a simple spectroscope and see what the emission spectra looks like.

Posted at 00:42:04 GMT-0700

Leave a Reply

297 Views