An alternative to the Potassium manganate diffusion prac' please.

C

clairelucas

COMMITTEE
Any tips for doing the melts? I've just ordered in and received the magnesium nitrate, but presumed a boiling kettle water bath would melt the mix, but looks like i'll need a rolling boil- should I be worried about the 2 oxidisers above a naked flame, as presumably that's what we're giving the yr7 kids?
Not that I worried about it before mind!
Over-thinking?
Have now melted in test-tube over flame, kept length of tube warmed so less residue when pour out into a spotting tile.Bit messy. Pellets could be more pellet-like... bit of a palaver
 
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A

Alan

Lesley Newcombe said:
We use a deodorant/perfume spray - squirt in the front of the class and get the pupils to raise their hands when they smell it!
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I was amused by your comment.

Many years ago, I read of an experiment done like this but without the smelly bit. After a short time people in the front row started to put up their hands followed by those behind until the non-existent smell reached the back row.
 
Annie

Annie

Alan said:
I was amused by your comment.

Many years ago, I read of an experiment done like this but without the smelly bit. After a short time people in the front row started to put up their hands followed by those behind until the non-existent smell reached the back row.
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Haha, so it can be both a diffusion demo and a herd mentality demo, depending whether the aerosol is scented or not.
 
Dino Girl

Dino Girl

Give CLEAPSS a call - sometimes it's listed as being harmful but actually isn't. We had the same thing with Methylene Orange.
 
Fallout_Girl

Fallout_Girl

We've got a pregnant teacher so we don't use it here at the moment. We've been using powder paint that we nicked from the art department for our diffusion demos. If I recall correctly potassium permanganate isn't especially harmful, but some strengths need neutralising before disposal which can be time consuming. We'd rather just use an alternative that can be washed straight down the sink.
 
C

clairelucas

COMMITTEE
clairelucas said:
Any tips for doing the melts? I've just ordered in and received the magnesium nitrate, but presumed a boiling kettle water bath would melt the mix, but looks like i'll need a rolling boil- should I be worried about the 2 oxidisers above a naked flame, as presumably that's what we're giving the yr7 kids?
Not that I worried about it before mind!
Over-thinking?
Have now melted in test-tube over flame, kept length of tube warmed so less residue when pour out into a spotting tile.Bit messy. Pellets could be more pellet-like... bit of a palaver
Click to expand...
And now my 'stock' of pot.permanganate in mag.nitrate tablets has gone liquid in the petri dish I was storing them in. Is that expected, that they have a short shelf life? Or is storage an issue- do they need to be kept somewhere special..? Any one else using them and having this problem?
Will check with CLEAPSS if not..
 
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Techno

Techno

clairelucas said:
And now my 'stock' of pot.permanganate in mag.nitrate tablets has gone liquid in the petri dish I was storing them in. Is that expected, that they have a short shelf life? Or is storage an issue- do they need to be kept somewhere special..? Any one else using them and having this problem?
Will check with CLEAPSS if not..
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Yes happened to us too, need to be kept in an airtight jar or it will absorb water
 
C

clairelucas

COMMITTEE
Did that work? Even the ones I did yesterday for today turned to mush..
Planning on keeping them double bottled with desiccant (like the group 1s) and see what happens for next time..
 
J

Jeff

We sometimes use onions in a frying pan over the bunsen on the front bench. The students put their hands up when they smell the onions.
 
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