ivory soap experiment (ptoe, oxygen)

Do you know what this is?????? Nope, it’s not shaving cream.

ivory soap3

It’s a bar of Ivory soap after being cooked in the microwave for a couple of minutes! It’s a very cool experiment that you must try with your little ones! I developed a little booklet to guide this experiment. This is also a great experiment to do with the PTOE when discussing Oxygen.

ivorysoap 3

For the experiment you need:

a bar of Ivory soap

downloadable booklet- cut pages in half then assemble and staple

large bowl of water

math cubes

newspaper or wax paper to protect table

ivory soap

 Our little friend Emma had all kinds of great questions about this experiment. She even wondered if the bar was hollow.

ivory soap4

After completing most of the booklet, it’s time to put the soap into the microwave:

1. Put the soap in the center of a large plate.

2. Cook the bar of soap on HIGH for 2 minutes. DON”T take your eyes off the soap, it’s very cool to see it expand into fluffy clouds.

3. Let it cool before touching, it can be VERY HOT!

So why does Ivory blow up in the microwave??

All soap contains water; both in the form of water vapor (inside trapped air bubbles) and water that is caught up in the matrix of soap itself. The soap expanding is caused by the heating of the water that is inside of the soap. The water vaporizes, making bubbles, while the heat also causes trapped air to expand. The heat also causes the soap to soften and become pliable. This effect is actually a demonstration of Charles’ Law. When the soap is heated the molecules of air in the soap move faster causing them to move far away from each other. This causes the soap to puff up and expand to an enormous size. Charles’ Law states that as the temperature of the gas increases so does its volume. Try a non-whipped bar of soap and see if Charles’ Law effects it too.

A little history of Ivory soap:

The concept of soap that floats was rumored to have been encountered by accident. The story goes that Harley Procter named the soap ‘Ivory’ from a biblical verse (Psalm 45) church: “All thy garments smell of myrrh and aloes and cassia, out of the ivory palaces whereby they have made me glad.” In 1878, the formula for the “White Soap” was created. Several months later the accident occurred. Without thinking one of the workmen left to go to lunch and the machinery was still running. Since the machinery was left in operation, air would work its way into the mixture. The workman decided not to discard the mixture after discussing with his supervisor. Instead he poured mixture into frames and the soap hardened. Interestingly enough it was cut, packaged, and shipped. Amazingly, Procter & Gamble began to receive letters from buyers of this “accidental” soap. They wanted more of the soap that floats! Even though this interesting formula was one of their best products, they were perplexed as to how this happened. The mysterious formula for the floating soap was resolved when the lunchtime accident was revealed. The error the workman made became Procter & Gamble’s new product. Why was this product so popular? Some people were known to bathe in the Ohio River and the floating soap would never get lost. Ivory Soap became a best seller due to a workman’s error. Proctor & Gamble makes the floating soap by intentionally adding a small amount of air in the formula. Naturally, this allows the soap to be lighter than water (from essortment.com).

What to do with the soap bits:

 1. After the experiment it’s time to play with the soap- Ivory soap sculptures!  Have a small bowl of water available to wet hands, this helps in the molding of the fluffy soap. If the soap is too dry it will not form well.

ivory soap2ivory soap

 Here are some of the lovely creations that the three little ladies made from the soap- a cave, a house,

ivorysoap 2 

and a little kitty!

ivorysoap 4

2. Add pieces to warm water and do some felting with wool roving. We are planning on making cocoons tomorrow!

3. Make a new bar of soap- melt the soap in a pan, add a bit of water, add oatmeal and lavender buds. Pour into a mold.

4. Make soap balls (the little ladies love these)-  put the soap bits in a bowl, add a touch of water,  add lavender or other dried flowers, and roll the mixture into a ball. Place on waxed paper to dry overnight.

 ivory soap 6

What a great activity to do during flu season! I guarantee clean hands in the end! Enjoy!


  • March 12, 2010 - 3:18 pm | Permalink

    Thanks for the fun experiment, my kids LOVED it! I posted on my blog too and linked to you!
    Thanks again,

  • October 14, 2009 - 1:20 am | Permalink

    we’re going to have to try this, wow!

  • October 3, 2009 - 8:56 pm | Permalink

    Robin, I’m not sure if any other soap company whips their soap. So I don’t know.

  • robin
    October 3, 2009 - 5:14 pm | Permalink

    neat! Tell me tho, does this just work with Ivory soap? Ivory stings our skin so we can’t use it.

  • Anet
    October 2, 2009 - 8:45 pm | Permalink

    I have to do this with Noah!!!

  • October 2, 2009 - 2:43 pm | Permalink

    I am so happy I found your blog. This is so going onto the list of things to do (when she’s older). :)

    Love the soap balls, if ivory soap didn’t dry my skin out on contact I’d be making these today just for kicks.

  • October 2, 2009 - 12:18 pm | Permalink

    very, very neat!

  • October 2, 2009 - 9:19 am | Permalink

    Um…how cool is that?! :) Thanks for passing this along!

  • October 2, 2009 - 7:14 am | Permalink

    I especially enjoy how it’s more than 1 poject for the same item. How interesting about how ivory soap was invented. I love these accidental finds.

  • tia
    October 2, 2009 - 12:40 am | Permalink

    so excited to do this ! my project list is growing daily , we love all the PTOE stuff.

    thanks so much !!

  • October 2, 2009 - 12:00 am | Permalink

    Very cool! I’m so glad you are doing and sharing all this PTOE stuff for my future reference. :)

  • Phyllis
    October 1, 2009 - 8:41 pm | Permalink

    I love this whole entry! What a wonderful way to spend some time. I did want to let you know however, that there is a typo in your little booklet. They are “Unifix” cubes, with an “i” not an “e.”
    Thanks for sharing with us!

  • October 1, 2009 - 3:15 pm | Permalink

    seriously cool. adding it to our list.

  • October 1, 2009 - 8:58 am | Permalink

    This is very cool. I don’t suppose you can do this without a microwave? We live in the dark ages.

  • October 1, 2009 - 8:41 am | Permalink

    I am amazed by the research, care, and detail which went into this series of activities. My scientific little boy would love to do this. love, Beth

  • October 1, 2009 - 8:04 am | Permalink

    Oh my goodness.
    This looks like so much fun!
    Totally making my list of rainy-day activities.

  • October 1, 2009 - 7:23 am | Permalink

    This is so cool!!! We don’t have a microwave but I ‘ll bet Nana will let us use hers :)

    I really like the idea of the lavender/ivory soap balls.

  • gracie
    October 1, 2009 - 3:13 am | Permalink

    it’s because of the water in the ivery soap that i buy it months before i need it, take the wrapper off, and let it ‘dry’ out making it last longer

    this experiment looks like fun! so i’ll buy some ‘new’ soap and try it with my young ones

    thank you

  • October 1, 2009 - 2:31 am | Permalink

    so cool lisa! besos-jane

  • October 1, 2009 - 1:12 am | Permalink

    We will be doing this one. I have lots of Ivory soap since I use it in my laundry detergent. :)

  • September 30, 2009 - 11:32 pm | Permalink

    What a cool idea! We’ll have to buy some Ivory next time we go shopping.

  • September 30, 2009 - 10:54 pm | Permalink

    Wow. Who knew that craft soap could be so easy?

  • September 30, 2009 - 10:46 pm | Permalink

    Neat! I’ve never heard of such an experiment. And, I love the soap ball idea!

    I bet it smelled wonderful. :)

  • September 30, 2009 - 9:56 pm | Permalink

    Oh it’s very cool.. I’ll have to try with my cousins. And a white corner view to boot. funny!

  • Renee
    September 30, 2009 - 9:48 pm | Permalink

    Fun! We need to try this!

  • September 30, 2009 - 9:44 pm | Permalink

    Awesome experiment and history. Thank you for sharing… we’ll be sure to do this one.

  • September 30, 2009 - 9:34 pm | Permalink

    What a great idea. I have some science loving kids who’d like to do this. I think I’ll save it for their next day off from school.

  • Comments are closed.