How to Make Chalk Rocks

I can’t remember where I first saw balloon sculptures made from plaster-filled balloons. And I just knew I wanted to try this with my kids and make chalk rocks. I couldn’t wait until my kids were old enough to do that activity!  

The triplets are old enough now!!

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chalk balls

How to Make Chalk Rocks

*This is a semi-dangerous activity, which is why we waited until our kids were nearing four to do this activity. The plaster is dangerous if inhaled in it’s original state and after it is mixed can get VERY hot. If you have triplets like I do, wait until your kids are able to follow directions and/or have another adult to help.*

Supplies to Make Chalk:

  • Bucket of Plaster of Paris – we mixed it 2 cups at a time
  • Disposable dish and utensils
  • Water
  • Funnel
  • Balloons
  • Bucket of Water – for rinsing any plaster bits that might get on your skin ASAP.

how to make chalk rocks

Directions for Chalk Rocks Kids Craft

Mix the plaster and the water together by the directions on your container.  

Add food coloring and mix quickly.  

It should look the consistency of pancake batter. Runny and some small lumps are okay. Add dye to your plaster – use more than you intend for the final product. It will lighten considerably in the finished product.

Put the balloon around the mouth of your funnel. Spoon the plaster into the balloon.  

We had to bang the side of the funnel to ensure that the plaster filled the balloon. Tie off the balloon – sorry, I couldn’t get that on video tape – not enough hands!

Then your kids get to squish the balloon until it gets really warm.

Once it is warm, try to form it into the shape you want the chalk rock to be when you are done. If it is too warm put the balloon down – most likely it is already set at that point.

chalk rocks from balloons

Wait a full 24 hours and then cut the balloon from the chalk rocks to reveal your artistic creation.  

Have fun coloring!

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Did your kids enjoy this fun activity? Let us know in the comments below, we’d love to hear! Also, be sure to join us over on our Facebook page.