Monday, July 9, 2012

Sparklers and Colored Fire

Probably my favorite part of our Fireworks Unit was this colored flame demonstration. We had talked about chemical compounds and their flame colors, but seeing them actually burn was just amazing. The first time we did this I used old mandarin orange cans to light the flames in, but then we wanted to do it again and glass bowls worked just fine too.

These are the chemicals we used. I had read that boric acid was available "at any pharmacy, as an eye antiseptic, or home improvement store, as ant and roach killer." I knew as soon as I read the words "readily available at your local ____" that I was in for trouble (I can never find anything that's supposed to be "readily available" at grocery stores etc.). And sure enough, none of the ant killers at Home Depot listed boric acid as an ingredient, and the lady at Walgreen's Pharmacy said she never carried it anymore. BUT, I lucked out and found it in this huge container at IFA (it's used for an eyewash in horses, apparently). IFA also had this antifreeze, brand-named HEET, which is just methanol. (I also saw some at 7-11.) Methanol is what you use to mix with the other chemicals since it gives you a nice clear blue flame. You just pour a little bit of each chemical (they're powdered) in your container, pour methanol over them, stir each to dissolve, and then light them.

We ordered the lithium chloride online here.

I just love this colored fire. I could have watched it burn all night. So pretty!

The idea for this next experiment came from this video here (subscription required). Basically, it just shows how they make sparklers: they use tiny bits of iron to create sparks. In the video he shows how you can file an iron nail and sprinkle the filings on a candle to make those same kind of sparks. We just decided to try it on the spur of the moment after watching the video, and I didn't think it would work since I didn't even know if our nails were made of iron or if I'd be able to get any filings from them. But they were and I did, and the kids  LOVED watching the sparks come from the candle. They even understood why it worked (more surface area=more oxygen, plus the smaller bits heat up faster) thanks to our study of combustion the day before.
The cast of characters


Thus prepared, we were able to enjoy our Fourth-of-July Sparklers at my mom's house even more! 

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