Australia's Science Forum

Hi Everyone! I've just done a search and have gone through 4 pages of posts but I can't find the recipe for elephants toothpaste!! I am hoping to do it tomorrow and have a very limited supply of H2O2 so I can't play around too much... Will someone please confirm this? I put some dishwashing liquid in the bottom of the cylinder, put some KI solution (fairly concentrated) in the bottom then add the H2O2? How much of each do I use??? I wish I had written it all down when I did it 2 years ago!! Had some great results (I just rediscovered the photos I posted when I did my search...). Anyway, hopefully one of you geniuses out there will get back to me by morning!
Rosalie

I must have written this down from when the topic was on before.

"30% peroxide in a large measuring cylinder, a good squirt of conc dishwashing liquid, and add a spatula full of KI. Stand back! Don't be tempted to touch the resulting foam, as it can burn, especially at the fingernails! However, the foam goes and goes and goes."

Doesn't say how much H2O2 though. I would imagine 100-200mls. Our peroxide comes as 35%, so I guess water it down a little if yours is the same. Good luck

Yep, did this yesterday, about 100mL of H2O2 in a 2L measuring cylinder with a good squirt of detergent (you don't need to worry about watering down the 35%), I use about 25mL of saturated KI solution, but straight KI works fine too.

THANK YOU, THANK YOU, THANK YOU!! So KI goes in last all good!! Hope it works... The 35% H2O2 has been in the fridge for quite some time so I'm hoping it hasn't turned to H2O... I'll do it in one of our plastic 500ml cylinders. Thanks again!!

I forgot how much fun that was!!! Kids loved it. We used the 1.5L coke bottles and nearly hit the roof of the covered area we did it in. Bits landed on my lab coat and everything. Just glad it didn't land in my hair!!! Ah, what a blast. Too much fun for the end of term... Now to clean up the labs and get lab coats ready for laundering over the break. Checking pockets etc. Oh the joys! But really had a great time with the little kids (yr 3&4). One of the things that makes me not want to quit my job... Still debating coming back next year or not. Well, that's enough rambling from me. Happy holidays everyone!!

Another alternative to this is to use a yeast suspension in plabe of the KI

Have you tried it this way Rowyrow? Sounds like a safe, cheaper alternative!

yep one of my teachers did it last term but we used a volumetric flask instead of a measuring cylinder with decent results .

A recipe I have is 100mls hydrogen Peroxide and 20-25mls 2M sodium Iodide. I was wondering if 2M potassium Iodide could be substituted. By what is written above I assume it wouldn't matter the concentration used.

Hi
we do it 2 ways. One way using 6%H2O2 and yeast and the other way is using 35% H2O2 and saturated potassium iodide. Link attached for the method we use with the yeast(just make sure you add the yeast to the warm water and mix well before adding it.
https://sciencebob.com/fantastic-foamy-fountain/

Does elephants toothpaste stain concrete? I can't remember from previous demonstrations. I don't want to upset anyone at my new school!

Products are oxygen, water and iodine. So I reckon don't do it on concrete, coz of the iodine. Probably even worse if you use the food colouring option.

RosalieL wrote: ↑18 Nov 2021, 11:48 Does elephants toothpaste stain concrete? I can't remember from previous demonstrations. I don't want to upset anyone at my new school!

Just pop it in a big tray with a drop sheet under. Good to go, no stain