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Has anybody done this in volumetric flasks? Have just been asked by a casual/temp teacher for the flasks, and I realised after he went what he is doing. Would the flasks explode because the opening is too narrow, for instance? Come to think of it, foam coming out of a volumetric flask would be rather narrow for an elephant! But just thought I'd run it by you clever labbies.

I wouldn't use volumetric flasks simply because they are so hard to clean and this is really not their purpose anyway. It is not as though he needs to do an exact dilution or anything so i can't see why it would HAVE to be a volumetric flask. This is the reason we chemists have conical flasks and beakers. Just give him conical flasks and make it easier on yourself.

Havent tried it, but if it didn't explode it would be pretty spectacular! If you had a plastic one that would be good. I've only used the plastic measuring cylinders to do it in cos I'm too scared of breaking the glass...

Good idea about the conical flask, Fiona!

I have only done this in 2L coke bottles so not sure about the volumetric flask.
Not very elephant size as you say.
I showed my daughter, who is primary school teacher, this and she did it for science day with year 2. She told them how the zoo had phoned to get her to make it for the new baby elephants. At the end of the day one of the kids ran up to her outside the school to make sure she was going straight to the zoo to deliver it.
How cute!
Helen

we use the volumetric flask,the teacher does it because of the strength of the peroxide.The teacher puts the flask in a plastic tub and The students then light the flints and poke the foam

The reaction generates a lot of heat. You would have to be very sure that your flask is a top grade glass... ans even then I would NOT risk it in glass case of breakage.

We use PET drink bottles, but the heat shrinks the bottle every time its used for a reaction

Thank you all for your input. Have just spoken with the teacher concerned, and he says he wants the volumetric flask cause it has the large surface area inside the flask and the small neck makes the toothpaste shoot out. I nearly pointed out that toothpaste should ooze, but decided that he wanted the shooting factor and wasn't receptive to my ideas! I'm still not convinced that it is particularly safe, although the flasks are made from borosilicate glass, top grade or not, I've no idea.
Thanks again

I use measuring cylinders. You get a tower of foam, that is quick to start with, and then ends up oozing.

This was demonstrated on "Sleek Geeks" last night on Channel 2 with Dr Karl, using measuring cylinder, conical flask and a 2L PET bottle.
Best result was the PET bottle as after the initial overflow the "toothpaste" shot up into the air.
I guess the conclusion would be that the narrower the mouth on the vessel used, the better shape/flow of "toothpaste"
I am going to try the safer method and see if it is as spectacular

Yeah, I saw that too! I impressed my husband as we were eating dinner at the time and I wasn't really watching till the guy said 30% H2O2. I said sounds like someone's going to make elephant's toothpaste. My husbands eyebrows actually shot up over his glasses!

yeah we do the elephants toothpaste in a 1l glass measuring cylinder but after watching sleek geeks, next time I want to do it in a coke bottle! that was soooooo cool. Better do it outside though, it looked pretty messy! They said there was a link to their website that gave a receipe using safer household goods so I'm hoping to check that out today

we have done both the measuring cylinder, and the coke bottles.
Both are really good in different ways. We usually do one onf each.. side by side.

Just make sure that if youre doing coke bottles...AND want to do repeat reactions.. just have a steady suply of coke bottles on hand...as I said before they do shrink...and it allows you to have a steady supply... ready with the KI isoln in them already I still am concerned about the glass volumetrics though. But top grade should be ok