Erupting Chocolate Ooblek

Chocolate Ooblek (3)

Today I made Veronika a new version of ooblek. Wanting to make this one stand out from the crowd, not only did this version feature chocolate, but it could explode! And yes this activity is toddler safe.

As a reminder ooblek is about 2 parts cornstarch to 1 part water. From there, there are so many ways to fancy it up. Unfortunately I messed up the texture of our ooblek from the get-go because I thought I had a full box of cornstarch in the pantry. It turned out I only had less than 1 cup left, and I’d already poured in over 1 cup of water to a plastic tub. So our mixture was on the watery side, not true ooblek.

But that’s okay, because there was more for Veronika to play with here! First, we sprinkled on cocoa powder in addition to the cornstarch. This was purely for the heavenly smell. Yum!

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We also added 2 tablespoons baking soda because we wanted our ooblek to erupt. (Note: Be careful, because the baking soda will offset the now-solid-now-liquid property of ooblek, as it will dissolve in the water).

To make the explosions, add white vinegar to squeeze bottles and squirt in a bit at a time. This is great for exercising those little fingers.

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Veronika almost couldn’t believe it when the first bubbles appeared. I had to help out with lots of the squeezing, but she was transfixed watching the eruptions every time the vinegar hit the baking soda.

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The resulting bubbles are really neat ones, too, almost like honeycomb, but with a quasi-solid texture. They won’t pop until you pop them!

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This made for lots of fun poking and prodding. Veronika was a little hesitant to get her hands messy, but adding a spoon helped her get in there.

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There also was also an added auditory component to the fun, thanks to the hissing sound whenever baking soda mixed with the vinegar.

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In sum, this project made for one happy girl!

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Messy Play

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Veronika’s old enough now for her first messy sensory play, and this little game is a baby’s first introduction to ooblek!

As a reminder, “ooblek” is a fantastic substance that acts like a liquid in some circumstances, and a solid in others.

To make a very basic version, combine 1 cup cornstarch and 1/2 cup water in a bowl. Add just a few drops of natural food coloring.

Messy Play (1)

I sat Veronika down in her high chair – with sleeves rolled up and bib on! – and got ready for the mess.

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Drip some of the mixture onto the highchair tray. It will drip like a liquid, but solidify once on the tray. You can run your finger through it, and leave neat designs.

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She seemed hesitant at first, which surprised me; this is a girl who loves to get her hands in her food. But soon, her little fingers were squishing through the mixture.

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I very gently spooned some right into her fist. She squished and squeezed!

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Ooblek is fun!

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What sensory play does your baby like? Please share in the comments!

Ooblek Two Ways


Ooblek comes from a Dr. Seuss book published in 1949, which I confess I’ve never read! But you don’t need to know the story to have fun with this mysterious substance – part liquid, part solid. They key lies in achieving the right ratio of cornstarch to water.

There are two ways I’ve found to do this: being precise, or just winging it.

If you want to do the former, enlist your child to help you pour 1/2 cup water into a large container (a disposable aluminum pan works perfectly). Add 1 cup cornstarch, then use your hands or a spoon to stir the mixture.


Travis prefers this method, because he enjoys measuring out recipes. Once we had our ooblek, he insisted on adding food coloring, so we made it green. This turned out to make the perfect neon green ooze.


For the “winging it” method, I dumped cornstarch into a tray first, and then had Travis help me add water until the ratio seemed right. This can be a fun way for kids to tinker with figuring out how and why the mixture works; we discussed solid versus liquid as two states of matter while we played, and how ooblek is a little bit of both.


Eventually Travis decided that this batch should be purple, but you can have fun with it plain white, of course!


Kids will likely find all sorts of ways to play with ooblek, including adding objects to the pan, pressing on it, stirring it – and of course dipping in their hands.


Have fun squeezing it and seeing what happens!