Put a bar of soap in the microwave and watch it expand to 6x its size right before your eyes! The Expanding Ivory Soap Experiment is a classic science activity that will fascinate kids and grown-ups alike.
The Microwave Ivory Soap Experiment is one of my favourite science experiments for kids because it’s so quick and easy, and it yields such fascinating results. There’s almost no prep required, and you don’t need any fancy supplies. All that’s required is a bar of Ivory and a microwave oven.
What happens when you put a bar of Ivory soap in the microwave?
Because of the high volume of air that’s whipped into it, when you microwave Ivory soap, it rapidly expands into a huge, fluffy cloud in a matter of seconds.
Who would’ve ever thought to put a bar of soap in a microwave I wonder?
I have no clue, but I’m glad they gave it a try because they discovered one of the best-ever science experiments for kids!
Can I do the Microwave Ivory Soap experiment with other brands of soap?
No, this expanding soap experiment should only be done using Ivory soap. The high air content in the Ivory brand is what makes the experiment work. If you use a different brand, your soap may not expand, and could even smoke and burn and ruin your microwave.
There’s no fear of that happening if you use Ivory bar soap.
Let me show you how you can do this experiment at home or in your classroom, and at the end of the post, I’ll suggest a few ways to use your fluffy, soapy results.
You’ll need 3 things to conduct the Ivory Soap Microwave Experiment:
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- 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 bar of soap. Use descriptive words as you take turns holding it, feeling it and smelling it.
Did you know that Ivory soap floats? It really does! That’s because of the high air content I was telling you about earlier.
If you have an extra bar of Ivory, you could drop the spare bar into a bowl of water to show the children how buoyant it is.
Note: I wouldn’t wet the bar that you’re putting in the microwave. I’m not sure how that would affect the science experiment.
Instructions:
Time needed: 3 minutes
How to Microwave Ivory Soap – Experiment
- Unwrap your bar of soap
Unwrap your bar of Ivory and place it on a microwaveable plate.
- Place in microwave
Put your plate of soap in the microwave.
- Heat for 1-2 minutes
Run microwave on high for 1-2 minutes. Today I set my microwave for 1:20. You can’t really overcook your Ivory, but it will eventually 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 the ivory expand right before their eyes.
It happens so quickly! It’s fascinating!
The Ivory will start to 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.
Caution! The plate and the 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.
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.
You can always microwave a cup of water with vinegar or lemon juice added to get rid of the smell.
I personally love the smell of Ivory soap. It takes me back to my childhood. Ivory was the gentlest soap back when I was a kid, so we used it for years as children. Because the scent brings back warm memories, I don’t mind that my kitchen smells like Ivory after doing the experiment.
If you think the soapy smell might bother you, open a window before microwaving your bar of soap.
Examining your fluffy Ivory soap cloud:
Once your soap has cooled off, it’s time to have some fun!
Let your children investigate how the soap has changed: what started out as a hard bar of soap is now a fluffy, crumbly powder.
Today, to let the children really explore the results of our experiment, 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!
Be sure to warn children not to put the powder in their eyes, nose or mouth. It IS soap after-all, and it would sting the eyes, and taste horrible.
What can you do with microwaved Ivory Soap?
We usually do this experiment when it’s time to make a new batch of Homemade Laundry Detergent. I make it with Ivory, Borax and Washing Soda.
The kids love helping me make laundry soap, and it’s a great way to use the results of this experiment.
Our favourite way to use our crumbled soap though, is for sensory play!
We grab a roll of toilet paper and some water and the hooligans whip up a clean mud, also known as ghost mud or fairy mud. It’s a moldable dough that smells wonderful and keeps the kids entertained for hours.
Why does Ivory Soap expand in the microwave?
To find out the scientific reason why the Ivory Experiment works, head over to Steve Spangler Science, and he’ll explain the science behind it.
More easy, inexpensive experiments:
- Crystallized Beach Rocks
- Giant Homemade Bubbles
- 2-Ingredient Cloud Dough
- 2-Ingredient Ghost Mud
- 3-Ingredient Puffy Paint
- 5-Ingredient Homemade Watercolours
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Jackie is a mom, wife, home daycare provider, and the creative spirit behind Happy Hooligans. She specializes in kids’ crafts and activities, easy recipes, and parenting. She began blogging in 2011, and today, Happy Hooligans inspires more than 2 million parents, caregivers and Early Years Professionals all over the globe.
jennifer Dyer
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
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
taylor
Could you put food color in it
happyhooligans
I imagine you could, Taylor.
Melaine
Yes, drop the food color on the bar before you expand it and watch the magic!
happyhooligans
Oh! That sounds cool. We’ll have to give it a try!
xubie
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
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.
Carolyn
love it!
Lizzy
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
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.
Faith
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
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.
Julie samples
I love love love your posts!
Terrie
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
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.
Jes
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.
Sheena Crain
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!
Michelle
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
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.
Michelle
Thanks for the advice!!!
AMY G
HOW LONG DOES THE SOAP STAY FLUFFY???
happyhooligans
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.
Ann @ Such a Mama!
I microwaved just a few small pieces at the and of the soap’s life. It made a nice small cloud that was perfect to toss in the kids’ bath!
Jenn
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
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.
wanda
hola!!!! alguien sabe si para si funciona el experimento con el jabón blanco común para ropa? no conozco otro parecido en Argentina. Gracias.
Julie
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!
happyhooligans
Ohhh, and it would smell so good too!
MJ Isolani
we always used Ivory soap on the Christmas trees too! But, you can only make snow for the trees with Ivory soap flakes… When they stop making those, that tradition died.
Nanny
I have never heard of it! Would you please post the recipe? That sounds great! (And we love the smell of Ivory too. My children and grandchildren are grown but I have some great grandchildren that would think Nanny is pretty special if she could do some of these things! I just found this site today and will use it often. Thank you so much for the easy and safe things to do with kids!
Becca
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
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.
Aaron
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
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.
Julie samples
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
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
Karen
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.
happyhooligans
Excellent point, Karen. Thank you!
Karen Carroll
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.
Phyllis
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.
julie
Can you use imperial leather ivory soap or only the brand ivory soap
happyhooligans
It’s the brand soap that you need, Julie. The one pictured in the post.
Redford
My kid had a great time taking this project for science week at school.
happyhooligans
Cool! What a great one for science week!
Emma
Hi can you use any soap or does it have to be ivory soap? Thanks Emma
happyhooligans
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.
Sel Gims
This is amazing! Can I use any version of Ivory soap of does it have to be the original version?
happyhooligans
I’ve only used the original, Sel. I imagine it would work with the others, but I’m not endorsing that as I can’t speak from experience. 🙂
Paul Callomon
Ummm…my kid did this experiment and now my microwave stinks of soap. I cleaned it thoroughly, but apparently some of the soap-laden steam condensed in the vent and I will have to dismantle the microwave to get it completely clean.
happyhooligans
I wouldn’t advise dismantling your microwave unless you’re qualified to do something like that. We’ve never had a problem with the scent lingering, but to neutralize any odours in a microwave (my son once microwaved a chocolate chip cookie for 3 minutes, and our microwave smelled like a bonfire), just put a cup filled with vinegar in, and microwave it for a minute. Let it stand in there until completely cooled. That worked for me with the cookie fiasco. 🙂
PATTY PARSONS
Love all your get ideas!!! Wondering if you can do cement objects like you do the beach stone?? Thank you!!
happyhooligans
I’m assuming you’re talking about the Borax Crystal experiment and not this Ivory Soap experiment, right, Patty? You could try crystallizing a cement object. I think it would work. I’ve seen others use sea shells and those worked nicely.
Connie Behrens
Does the ghost mud keep for a while in a covered container?
Jennifer W
I do this when “making” diy laundry soap! Take fels naptha or zote soap, microwave as described here, then follow directions on WellnessMama or other sites for making homemade laundry soap.
(Special tip: don’t want to lose your favorite laundry soap but don’t like the price? Mix the two! Same scent but much stronger!)
Enjoy!
Patricia Fry
caution: if you use an old bar of ivory soap it will crack and burn only. So disappointing but our bar was close to 10 years old.
T Holland
Just stumbled on this idea and can’t wait to try it with my boys. I don’t usually but happen to have a large pack of this soap and the reason for having it is why I wanted to post! Another great use for the soap after it’s microwaved is to spread around in a garden or area being eaten by deer. We bought it to shave around our two baby trees to prevent these beautiful animals from tearing up the young bark. They deter them because they are very potent “human” smells!