A suitable demo?

[Wayne]

I have been asked to post this on here by another school.

The following is the procedure that was put on Riskassess by the teacher requesting the prac. It is to be a teacher demo.

1. Add a third to half of a teaspoon of solid CuCl2 to a medium beaker (250 mL).
2. Add approximately 5 mL of ethanol and stir well.
3. Repeat steps 1-2 for all other solid salts, including: SrCl2, LiCl, and NaCl.
4. Light up a light stick using a lighter.
5. Light up each beaker at a safe distance away from them, using the lit-up stick.

What are peoples thoughts?

[Marama T]

Well, RiskAssess says of ethanol "HIGHLY FLAMMABLE; DO NOT USE NEAR IGNITION SOURCES." Enough said, surely. And what is this safe distance? Will it be done in a fume hood or a lab? And for heavens sake, do not take it outside! I would refuse to get this ready.

[Anna Z]

Our teachers do this demo. Is done in a fume hood and a lab tech is always on hand. We use smaller quantities though. I can't see an issue with it.

[bigmack]

Sometimes you just have to have a go and see how bad can it be .Nobody said “don’t try this it at home “ so he we go.

Half a teaspoon of Salt and 5mls of Metho .Stirred in a standard old Drinking glass , not even a borosilicate Beaker , it may crack .

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Lighting stick? Guess thats a safe way to light it . I’ll use a match , thats more dangerous .

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A nice little whosh of flame and its away .
No burnt hand , no singed eyebrows. No exploding glass .

The flame burns mostly in the glass but peaks of flame maybe a few inches at most above glass .

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The flame burns for almost 2 minutes producing a nice yellow/orange flame that I’d expect from Sodium .

All that is left in the glass is some salt that is easy to clean out .

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I’d call it a pretty save experiment . I agree with Anna that you could use maybe even half that amount of each and it will still burn for a minute . Thats got to be long enough to observe .

[Marama T]

Cool!

[ELIZABETH]

https://www.youtube.com/watch?v=9oYF-HxtoIt's
It's essentially the same as the demo we do here.....a small amount of the salt in a crucible lid with a small volume of ethanol lit with a long match.
Spectacular in a darkened room!

[Anna Z]

One of our crazy old school chemistry teachers has a 1 M long piece of wood, has drilled little divots in it about 10cm apart. I fill each divot with a salt, we splash ethanol over the top carefully and light her up. Lovely in the dark all the coloured flames.

[Marama T]

That's excellent. I must tell the chem teachers.

[Wayne]

Thank you for the replies. I have passed the info on.

[mtg]

It's a bit like Dragons breath. Crazy physics teacher tried it but sprayed it thru a fire stick (broom handle with a lit taper attached) caught broom handle on fire, droplets onto the floor, also on fire. I decided it would not be a good demo. This idea is better.

[macca]

We used to do the Flour bomb demonstration, but alway did it outside. Don't seem to have as much fun anymore.
https://www.youtube.com/watch?v=CnqPZhX-jtI