Ivory Soap Microwave Experiment

Ivory Soap Microwave Experiment:  “Wow” kids and grown-ups alike with a quick and easy science experiment that you can do at home.

We do the expanding Ivory Soap science experiment a couple of times a year here in my daycare, and it never fails to impress and excite us.  It’s one of our favourite quick and easy science activities, but the process and the results are nothing short of awesome!  This is an experiment that never gets old, no matter how many times we do it.

The amazing expanding ivory soap science experiment

Today, I’m going to show you how you can do the Ivory experiment at your house or in your classroom, and at the end of the post, I’ll suggest a few ways to use your soapy results.

You’ll need 3 things to conduct the Ivory Soap Microwave Experiment:

Bar of Ivory Soap ready for the microwave

For your convenience, this post contains affiliate links.

  • bar of ivory soap (do not try this with any other brand of soap)
  • microwaveable dinner plate
  • microwave 

Getting started:

Before you begin, you can take a few minutes to let the children examine the soap.  Use descriptive words as you take turns holding it, feeling it and smelling it.  If you have an extra bar of Ivory, you could drop the spare bar into a bowl of water to see how it floats.  I just wouldn’t wet the bar that you’re putting in the microwave.  I’m not sure how that would affect the science experiment.

Conducting your Ivory Soap Experiment:

  1. Place your Ivory on a microwaveable plate
  2. Put your soap in the microwave
  3. Run microwave on high for 1-2 minutes.  Today I set my microwave for 1:20.  You can’t really over-cook it, but it will reach a point where it stops expanding.

You’ll want to pull up a chair or stool for your child to stand on so they can watch what happens to the soap in the microwave.  This part of the process is fascinating!

Ivory Soap expanding in microwave, such a neat science activity!

The soap will start to rapidly expand at about the 15 second mark.  To see it rolling, writhing and expanding as if it were alive is really exciting!

When your microwave stops, remove the soap and examine it.

preschoolers examining expanded ivory soap

Doesn’t your kitchen smell amazing?  Don’t worry, that smell should leave your microwave quickly, and it will not affect the flavour of any cooking you do.

microwaved Ivory Soap for our incredible science experiment

Caution!  The plate and soap will be quite hot for a minute or so after being removed from the microwave.  They cool down quickly, but give the soap a few minutes before letting your children handle it.

Examining your fluffy Ivory soap cloud:

Once your soap has cooled, it’s time to have some fun!  Let your children investigate how the soap has changed.

crumbling microwaved ivory soap with our hands

Today, I placed our puffed up soap in a large baking dish and the girls chopped it all up with paté knives.  They also rubbed it between their hands to crush and crumble it.  This is such an amazing sensory experience.  The soap is so smooth and silky.  It feels lovely, and it smells incredible!

chopping up ivory soap out of the microwave

What can you do with the results of your Ivory Soap experiment?

We usually do this experiment when it’s time to make a new batch of our Homemade Laundry Detergent.  Grab the recipe for my detergent, and your children can help you turn your soap powder into laundry soap.

Our favourite way to use our crumbled soap though, is to use it for sensory play!  We grab a roll of toilet paper and some water and the hooligans whip up a batch of ghost mud or fairy mud.  It’s a moldable dough that smells wonderful and keeps them entertained for hours.

Ivory Soap Experiment awesome science activities for preschoolers!

Head over to Steve Spangler Science to find out the science behind the Ivory Soap Microwave Experiment!

Expanding Ivory

Looking for more easy, inexpensive experiments to do with your kids?  Try our:

Science Activities for Kids

Giant Homemade Bubbles

2-Ingredient Cloud Dough

2-Ingredient Ghost Mud

3-Ingredients Puffy Paint

5-Ingredient Homemade Watercolours


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  1. jennifer Dyer says

    I absolutely love your web page! I’m always reposting! Keep up the great posts and pictures! I’m a mother of an 8 yr old son who has a form of autism, and I cannot say enough wonderful things about this group!!! But a huge thank you!

    • happyhooligans says

      I’m so glad you’re enjoying my posts, Jennifer. I love that the things that I do in my small home-daycare are inspiring moms like you to get creative with your own hooligans! x

  2. xubie says

    I have found with kids, food coloring is dangerous! As it stains everything and anything. I stay clear of it since I made snake bubbles outside last summer with the kids wearing garbage bags over their clothes. Little did I realize it would take a couple of weeks to get the food coloring off their feet and the bubbles that blew onto the patio stained that too. No more food coloring for this grammie! (esp since the patio was not mine but their dad and moms! Yikes!)

    • happyhooligans says

      A couple of weeks? That’s some strong food colouring, Xubie. We use food colouring at least once a week here, both liquid and gels, and we’ve never had staining like that. My hands usually get the worst of it because I do most of the hard-core mixing, and they’re always clean by the end of the day. A few hand washes, and it’s gone.

  3. Lizzy says

    Is there something special about Ivory soap? I’m in Australia and I have never seen it but would love to try this with my grand kids :)

    • happyhooligans says

      Yes, there’s a link near the bottom of the post that takes you to Steve Spangler Science’s website, where the scientific part is explained, Lizzy. It all centres around the Ivory soap, and why it’s different than other brands.

  4. Faith says

    Be careful doing the ivory soap in the microwave. We had this done at an in-service training and the fumes coming from the microwave bothered those of us with asthma problems.

    • happyhooligans says

      Thanks for mentioning that, Faith. No one here has any respiratory problems, so I hadn’t thought to mention that it might be a problem for those who do.

  5. Terrie says

    is there a reason you can’t use any other type of soap, I wanted to know if I could try it with dove ?

    • happyhooligans says

      It’s the high air content that makes this work, Terrie. I can’t say if it will work with other brands. It could just burn. I really don’t know first-hand.

  6. Jes says

    I want to go home and do this experiment right now… my little one is only 9 months old, but I’m putting together an activity book with all of the experiments / activities I want to try in the future. This will be a favorite, I am sure.

  7. Sheena Crain says

    Sounds fun. My daughter will love this since she loves to be in the kitchen with me. I shared this to my page because pretty much all of the women in my family are into kids activities. Thanks and keep them coming!

  8. Michelle says

    We did this experiment and loved it!!!! However it did bake my microwave stinky…would there be any advice on how to get the smell out? Did I over microwave the soap??? Yikes! !

    • happyhooligans says

      You might’ve, Michelle. My microwave has never smelled for more than a few minutes after doing it. How about microwaving a coffee cup filled with water and vinegar for a minute or so after Leave it to sit in there for a half an hour. Vinegar is good for absorbing odours. Then give the microwave a wipe, and maybe the scent will be gone.

    • happyhooligans says

      It will stay that way until you crumble it up, Amy. Although it looks fluffy, it’s actually hard and solid, but can be crushed to a powder easily just by squeezing it.

  9. Jenn says

    my soap didn’t expand that much so wonder if it made a difference if you let the bar sit out to harden or if maybe the soap was too old? I did use ivory soap.

    • happyhooligans says

      I would give it a try with a newer bar of soap, Jenn. I wouldn’t let it sit out to harden or dry out. I’m thinking the moisture in there would be a good thing.

  10. wanda says

    hola!!!! alguien sabe si para si funciona el experimento con el jabón blanco común para ropa? no conozco otro parecido en Argentina. Gracias.

  11. Julie says

    Ivory soap suds was what my mom used to decorate the Christmas tree when I was little. It created a wonderful snow effect. It is a treasured memory now that brings a smile each time I think of it!

  12. Becca says

    I am doing a science experiment in my college physical science class for elementary teachers and I cam across this and I thought it would be a good thing to use for measuring also! You could measure how much foam it makes and I am also doing the experiment with Dial soap so I will let you know if other soaps do this also! Thank you so much for this it gave me wonderful ideas and all the links to other things you did I absolutely love those I so love being creative and doing crafty things and since I found your website and all your pages I will always just come here and find some fun things to do!!! Thank you so much again! :)

    • happyhooligans says

      I’m so glad you’ve found us, Becca! I’m so glad you’re enjoying my site! Do be careful using Dial. In fact, I actually wouldn’t recommend trying it with any brand other than Ivory because the air content isn’t as high. I’ve heard other brands can smoke and burn and actually ruin a microwave.

  13. Aaron says

    Okay this is a mediocre experiment at best. I agree that the effect is cool and I plan to do this with myself when I get home. But the whole point of a science experiment is to explain why something happens not just that it does. Do a little research and find out why the soap expands in such a way. The experiment itself is pointless unless you can teach your children something.

    • happyhooligans says

      Gosh, i hope you’re teaching your children to be a little kinder and less critical of others, Aaron, but anyway… regarding your point: that’s the reason I’ve provided the link, near the bottom of my post, to Steve Spangler’s Science page – so you can find out the scientific reasons for the soap expanding. Perhaps you didn’t read far enough through my article to see the link, and just jumped to conclusions. In any case, even if I hadn’t provided the link, a parent could certainly research the science behind it themselves, before doing the activity at home. Gee, hope your day gets better, Aaron. Sounds like you’re off to a cranky start.

  14. Julie samples says

    It’s a wonderful experiment! Nothing mediocre about it at all!! Love seeing the excited faces and squeals of delight screaming ” it’s magic!”. I love your posts ! Ignore the negativity!!

    • happyhooligans says

      Thanks Julie! It’s a shame that some people are just so darn unhappy that they feel the need to pass their negativity on to others. I love your exuberance and zest for life! Thanks for lifting others up instead of knocking them down. x

  15. Karen says

    Science begins with curiosity. Science “magic” leads to science exploration. If you begin with hard core experiments you can lose the wonder. Keep exploring and sharing. This looks like a great place to start.

  16. Karen Carroll says

    According to Merriam-Webster.com, the definition of Science is as follows:
    sci·ence noun ˈsī-ən(t)s
    : knowledge about or study of the natural world based on facts learned through experiments and observation
    : a particular area of scientific study (such as biology, physics, or chemistry) : a particular branch of science
    : a subject that is formally studied in a college, university, etc.

    Precious children learn as much from the loving care of the person who spends time helping them enjoy life as they do from a rigid set of steps toward a focus that does not hold their interest. This Ivory experiment has exciting factors that enhance the learning and the desire to seek further knowledge about the children’s observations.
    Impressionable minds remember what truly interest them. When education is bathed in genuine care and concern for the educated, questions will arise that prompt even more learning.
    Thank you for your “Clean Fun” suggestions, and for your comments on the reasons that we should use Ivory.
    True Science has qualities often unseen to the closed heart and mind, and, as with most of life’s lessons, there are appropriate levels of explanation. Your little ones are blessed to have you.

  17. Phyllis says

    I agree with MJ – sad that Ivory Flakes are no longer made. When I couldn’t find any, I improvised by making my own. I used a vegetable peeler on bars of Ivory soap to make my own flakes. It whipped up pretty good and my daughter and I were able to make a small snowman. This microwave method sounds a little easier so I can’t wait to try it.

    • happyhooligans says

      You definitely need Ivory for this experiment, Emma. It’s the high moisture content that make the expansion possible. Other soaps may just heat up and burn, and ruin your microwave.

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