Amaze a Science Class With Elephant Toothpaste

This experiment shows the decomposition of hydrogen peroxide catalyzed by potassium iodide. The reaction is done in a tall graduated cylinder so that the foamy product shoots out very quickly in a tall cylindrical shape; hence, the name elephant toothpaste.

tall graduated cylinder (at least 500 ml)
food coloring
Dawn detergent
30% hydrogen peroxide (H202)
saturated solution of potassium iodide (KI)
disposable gloves
splint (optional)


1. Wear safety goggles. Also, wear disposable gloves when pouring 30% hydrogen peroxide, as it is a very strong oxidant.
2. Do not stand over the graduated cylinder because steam and oxygen are produced quickly.


1. Place a garbage bag or other covering on the lab table and possibly on the floor.

2. Fill the vial containing potassium iodide with water. Cap and shake until all the potassium iodide is dissolved (This should now be a saturated solution of KI made with 15 grams of KI and water.) Set aside.

3. Put on disposable gloves. Pour 80 ml of 30% hydrogen peroxide into a graduated cylinder.

4. Add about 40 ml of Dawn detergent to the hydrogen peroxide. Swirl to mix

5. Tilt the graduated cylinder and drip red and/or blue food coloring down the sides of the graduated cylinder to make your toothpaste striped

6. Quickly add the saturated solution of KI solution and stand back Be sure to move your hand away from the top of the graduated cylinder quickly or the hot foam will get on your hand and arm.

7. You may place a glowing splint in the foam to test for oxygen, but do not drop the splint into the graduated cylinder. The splint will relight indicating the presence of oxygen.


The rapid catalyzed decomposition of hydrogen peroxide produces O2 gas which forms a foam with the liquid detergent:

2H2O2 (aq) -> 2H2O + O2 (g)
The I-1ion is a catalyst for the reaction. The brown color of the foam is evidence of iodine in the reaction. It will stain clothes, skin, and carpet


Leave the gloves on while cleaning up. The foam and solution left in the graduated cylinder may be rinsed down the drain with excess water.




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    60 Discussions


    2 years ago

    how much water do we need i'm a bit unsure

    Terezi Pyrope

    3 years ago

    So can some one please dumb down how elephant toothpaste work. I just started middle school so.

    1 reply
    IreneC41Terezi Pyrope

    Reply 2 years ago

    The chemical stuff gets added to the other chemical stuff making it go really really fast.


    2 years ago

    I use Baquacil and KI in my science class - it is pool shock available at any pool supply store. You can also use yeast - you just have to prep it ahead of time to allow it to activate


    9 years ago on Introduction

    A few words on this experiment and Hydrogen Peroxide. Firstly if you are wishing to try this experiment I highly recommend you use Magnesium Dioxide as the catalyst instead of Potassium Iodide, It doesn't stain everything it touches like Iodides do. (also most metals work well as catalysts, Iron, Silver, copper all are really good, try iron filings :D) Secondly, Hydrogen peroxide above 6% is quite hard to obtain if you are not buying it from a chemical supplier, as a researcher, or business. 100% hydrogen peroxide essentially doesn't exist, at that concentrations near to 100% it decomposes explosively, and as such is near impossible to obtain anything higher than 70%. If you attempt to concentrate Hydrogen peroxide from a 3% or 6% solution, by evaporating the water (H2O2 boiling point is 15oC) you will in fact reduce the concentration as at higher temperatures the peroxide will decompose exponentially higher. Also be aware that peroxide is acid stabilized (a small amount of acid is added to prevent decomposition) and at pH of about 10 it will decompose on it's own in a matter of days. Good suppliers of lab grade (30-35%) peroxide are VWR and Sigma Aldrich, though these companies will definitely not sell to kids (under 18's) or to persons without legitimate reasons (for example I work in research of peroxide sterilization). Hydrogen peroxide, particularly of this grade is controlled as it is a precursor to a number of explosives. Hope this helps answer the questions which seem to appear in the comments If you wish to know more about Hydrogen peroxide, the following text is fairly comprehensive: "Hydrogen Peroxide" Schumb, Wentworth, Satterfield. 1955 ASC Monograph 128. (can be a bit hard to find however)

    3 replies

    You can actually get 20, 30 even 40% H2O2 easily from a beauty supply shop. My 14 year old went in and bought it without any questions! >:-(,default,pd.html,default,pd.html


    Reply 3 years ago

    Developer is not labeled by concentration 20v is 6% 30v is 9.9% and 40 v is 12%. Also available is 50 v wich is a 15% concentration which at least in my state can only be purchased by some with a cosmetology license.

    The links provided are for 20 and 40 vol peroxide.
    The vol system is not the same as the % concentration.
    the vol is the volume of oxygen generated when the volume of peroxide is decomposed.
    So for a 1 liter solution of 40 vol (12%) peroxide this produces 40 liters of oxygen when decomposed.
    As a guide each 1% is about 3.3 vol.

    This is however a higher concentration then I expected to be available.
    thankyou for your reply.


    3 years ago

    Hi, thanks for the cool video and the instructions. I was wondering if food grade 35% hydrogen peroxide would work???

    I am a high school senior at a STEM school who works with a club doing experiments for younger students. Do you have any suggestions as to where I can find hydrogen peroxide? I already have a bottle of 100% potassium iodide.

    Thank you for your help.


    9 years ago on Introduction

    Looks like something from, "Demolition Man" with the car seen. LOL


    i think think you might be able to get the stuff at united, and they have a bunch of other cool stuff too.