Peter Sigsworth
COMMITTEE
Elephants' toothpaste - or should it be elephants' sneeze!
- Thread starter Peter Sigsworth
- Start date
Peter Sigsworth
COMMITTEE
that's the height it wentNext time use red food colouring and do some blood pattern analysis.
Peter Sigsworth
COMMITTEE
Before anyone says it - it was an online demo for a group self isolating - teacher said 'make it as good as you can' I replied should be done outside with maximum safety precautions - full PPE and screens just in case the flask breaks. she said - 'no chance of it breaking I've done it loads of times!!'
Afterwards - she was a bit flustered and said 'should have done it outside good job I had the safety screens!!!'
'You can lead a horse to water but you can't make them drink'
I finally said 'how are you going to get the mess off the roof?' and left it with her.
Afterwards - she was a bit flustered and said 'should have done it outside good job I had the safety screens!!!'
'You can lead a horse to water but you can't make them drink'
I finally said 'how are you going to get the mess off the roof?' and left it with her.
Peter Sigsworth
COMMITTEE
You need to use a vessel which has a narrow neck the constriction increases the force of the foam coming out - I use a 2L volumetric flask. The Potassium Iodide must be as saturated as possible ie keep adding the solid to water until no more will dissolve. The Hydrogen peroxide must be 100vol (30%). Put up safety screens round the flask (just in case it breaks) and make sure this is done outside with the audience at a suitable distance and wearing safety specs.
You must wear lab coat gloves and safety goggles (and/or face shield).
Mix 200ml H2O2 with some fairy liquid and food colouring, pour into the flask. Quickly tip 50-100ml of the saturated KI solution (depending on how violent you want the reaction to be) into the flask and move away as quickly and safely as possible whilst continually watching the apparatus.
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Peter Sigsworth
COMMITTEE
probably - 1L flask with half quantities? You'll have to have a playIn theory, a smaller amount with a tighter nozzle would also hit the ceiling, correct?
No you cannot make an elephants toothpaste thrower!In theory, a smaller amount with a tighter nozzle would also hit the ceiling, correct?
Peter Sigsworth
COMMITTEE
Not quite - 'Schools are advised NOT to deviate'. Contact them for advice and new RA if they do. There were no children present when we did this - online lesson
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In the past we have uses very small quantities (about 20mls H202 and 5mls of KI) in a measuring cylinder it does quite well for making the point but its not exactly spectacular. Makes it very easy to clean up as everything stays within a tray. Our teachers rarely use demos which I want to encourage them too. So making it more WOW would be great I will have to experiment with scale when I have more time.
I was thinking more like a bottle rocket done outside but perhaps the mixture wouldn't be great for the grass pitches.
Tried this an it worked to an extent. Problem is not the damage to the grass but getting rid of the corrosive foam.
Do it in the carpark and in a paddling pool
I will have to try this next timewe had a chemistry teacher who liked to put a smoldering spill next to the foam to show the O2 produced. Went up with a huge woosh once. Scared the sh*t out of us but the kids loved it