Cloud Soap Experiment

Cloud Soap Experiment, Wee Warhols, Ivory Soap, STEM, STEAM, Austin, science

Looking for a fun and easy at-home project? My boys love this Cloud Soap Experiment! They get to watch a bar of Ivory soap expand and cloud up in the microwave — it’s pretty amazing.

All you need:

  • At least one bar of IVORY soap
  • A different brand’s bar of soap for comparison
  • A plate
  • A microwave

Let’s start testing

For years Ivory’s claim to fame was its ability to float (no groping around in a full tub for the soap during bath time) and its purity. But your kids probably don’t know this so this difference between Ivory and other brands is a fun place to start your testing.

We use Dove in our house so that was our comparison brand. The boys made predictions about whether or not either of the bars would float. The verdict? Both would sink.

Soap experiment, Wee Warhols, Austin, STEM, STEAM
Float or Sink?

The Ivory soap floated and the Dove bar sank.  Why is Ivory soap the only soap that floats?  Well, I’ll try to explain, but if you want an expert to tell you, look here.

What makes Ivory different?

If you clicked the link above, you know, but this is all about guiding your kids through an experiment. Baron suggested that Ivory might be hollow, which is why it floated. Good guess! We decided to look inside the bars of soap.

I knew my husband wouldn’t want his fancy knives used to cut soap so I tried to break Dove bar in half. No luck. Then I tried to break the bar in half. No problem. Another clue for my little scientists!

soap, air pockets, Wee Warhols, experiment
Fluffy Air Pockets

Inside the the bar of Ivory you may be able to see tiny air pockets that are whipped into the soap when it’s produced. That’s the secret to Ivory’s floating soap — the whipped-in air makes it less dense than water.

Now for the fun part!

Now that you’ve discovered that Ivory is different, let’s see what happens when you microwave it for two minutes! (Spoiler alert: it turns into a big cloud)

An adult should always be present when using the microwave and when the cloud comes out, it’s going to be very warm. I advise waiting a minute before touching it.

Wee Warhols, Austin, Ivory soap, experiment, STEM,
Growing Cloud of Ivory Soap!

So Cool!  They boys and I were surprised by the texture of the cloud.  You think it is going to be so soft, but they described it as more “papery.”

Why does Ivory turn into a cloud?

This is actually very similar to what happens when popcorn pops or when you try to microwave a marshmallow. Those air bubbles in the soap (or in the popcorn kernels or marshmallow) contain water molecules. Water is also caught up in the matrix of the soap itself. The expanding effect is caused when the water is heated by the microwave. The water vaporizes and the heat causes the trapped air to expand. Likewise, the heat causes the soap itself to soften and become pliable.

Steve Spangler

Putting the A in STEAM

Well, of course I couldn’t stop there. I love integrating art with STEM activities and why not make use of our fluffy Ivory cloud?

We got out our  IKEA Ice Tray Molds and made some small soap forms.  You have to do this when the cloud is pretty warm or it will all flake away.

IKEA, Soap, Molds, Austin, Wee Warhols
Formed Soap

No fun-shaped molds? No problem!

  • Heat the oven to 400 degrees
  • Put parchment paper on a cooking sheet
  • Set out some metal cookie cutters like these fun ghost ones on the parchment
  • Scoop your cloud mixture into the cookie cutters
  • Cook for 4-5 minutes
  • Take out and pat down with something (I used a set of chopsticks)
  • These aren’t very strong so gently release
Halloween, ghost, soap, molds, Wee Warhols, Austin
Ghost Soap Molds

This is when I tricked one of them into taking a bath!

soap molds, Wee Warhols, Austin

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Updated photos below. My babies are so grown up!