Supersized Elephants Toothpaste

Globetrotters-2010

OK, I have to admit that we really, really like the classic elephants toothpaste demonstration at Imagination Station.  Combine a mixture of hydrogen peroxide and dish soap with a catalyst like sodium iodide and you get a foaming tower of, well, foam!

We like it so much that we do it everyday as part of our Method to the Madness demonstration. We have featured it on our weekly science segment Imagine-it on WTVG13 and on an episode of WTOL AM Saturday where we re-branded it “Dinosaur Toothpaste” because of the fossil exhibit we had at the science center at the time. Heck, we have even done it inside a pumpkin for Halloween where it squirts out the face to make a foamy mess.

Earlier this year, when the Harlem Globetrotters were in town we were asked to do some sort of experiment as part of the half-time show. What better thing to do than a giant version of our favorite chemistry demonstration? Check out the video below for an example of the kid-safe at home version and a much larger multi-flask version that looks very cool.

When we do this again, and we will for sure, we will definitely add a whole lot more food coloring to the hydrogen peroxide to get much better colors in the foam that shoots out. Since the 35% hydrogen peroxide “expands” about 100 times in volume, we will have to add a whole lot of coloring to get a really nicely colored foam.

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About the author

Carl Nelson is the Chief Scientist and Exhibits Director at Imagination Station in Toledo, Ohio. He holds a Masters Degree in Experimental Physics from Michigan State University and has been having fun exploring (exploding?) science in Science Centers for the past 19 years.
 

Comments

10 Responses to “Supersized Elephants Toothpaste”
  1. Sui Sum Olson says:

    What is the concentration of the sodium iodide and th approximate amounts of soap and hydrogen peroxide?
    Thanks for your help.

  2. Carl says:

    Hi Sui Sum,
    There are a couple ways we do this demonstration. In a 2 liter graduated cylinder, I’ve found that 200 ml of 35% hydrogen peroxide, 50 ml of 2 Molar potassium iodide solution and a few squirts (~20ml) of Dawn detergent works great. You get a nice vertical expansion of the foam and then a nice lateral expansion once the foam flows down the side of the cylinder. If you are using a 4 liter flask, then try 500 ml of 35% hydrogen peroxide, 50 ml of 4 Molar potassium iodide and about 20-30 ml of Dawn detergent. This should create a rapid expansion and 10-15ft tall jet of of foam.

  3. Nevex says:

    Is sodium iodide an edible substances

  4. Carl says:

    Hi Nevex,

    Yes, technically Sodium Iodide is edible. The physiological effects depend on many factors.

    Carl

  5. John says:

    Hey Carl!

    Have you tried to use Potassium Iodide as a catalyst? What are the best amounts in this case?

  6. Rachael says:

    Hi Carl,

    I’d like to do a version of this demo at an elementary school near where I grew up (lo these many years ago!) and would be interested in asking you some questions about reaction scale and obtaining reagents if you have the time. Thanks so much!

    Rachael

  7. Carl says:

    Hi Rachael,

    Send me an email with your questions and contact information to carl@istscience.org and we can talk about the details of the demonstration.

    Carl

  8. Carl says:

    Hi John,

    I have used both potassium iodide, sodium iodide, manganese dioxide and bakers yeast as a catalyst. They all will catalyze the reaction, each with differing effectiveness. We have settled on potassium iodide for our demonstrations as it is less expensive than sodium iodide and appears to work as well. Regarding amounts I would use: 50ml (2 molar) KI, 250ml 35% peroxide, and a dash of dawn detergent (less than 50ml). This works great in a graduated cylinder. If you are using a 2 liter flask, I’d use 50ml of 4 molar KI, 500ml 35% peroxide and a dash of dawn detergent (less than 50ml) to get a nice jet of foam.

    Carl

  9. Karen says:

    Hi Carl!

    I love this demo — I’m hoping to do it for a junior high assembly in a couple of weeks! Quick question: is it possible to get a nice jet of foam if the experiment is scaled down to 1L flasks? In such a case, would you recommend 250 mL of 35% hydrogen peroxide and 25 mL of 2M KI?

    Alternately, for a 2L flask, would you recommend 250 or 500 mL of 35% hydrogen peroxide?

    Thanks so much! As a college kid who LOVES science outreach, y’all have my dream job. Best,
    Karen

  10. Carl says:

    Hi Karen,

    Well, we use 500ml in a 4Liter flask, with 4M KI and 35% hydrogen peroxide. I really haven’t played with smaller size flasks, so you might just experiment and see. My first guess would be that things should scale down. So I would try 250ml of peroxide, and 25-50ml of 4M KI solution. Just watch out for the quick reaction and get your hand out of the way quickly!

    While the jet is cool, don’t dismiss the Wow factor of the laterally growing 2 liter graduated cylinder. For that we use about 250ml of peroxide, 50 ml of 2molar KI, a dash of soap (30ml?).
    When you add the KI the foam flows up the cylinder, over the sides and then grows laterally. If you have fresh 35% peroxide, the ball of foam is quite impressive.

    If you get a chance, let me know how it works with the smaller size flask!

    Good luck,
    Carl

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