My two little girls are growing so fast! Isn’t it amazing how it happens? As they grow I try to come up with different activities that keep them engaged. This fizzing galaxies toddler activity is a great way to introduce science projects, hone their fine motor skills, and keep them interested in an activity for more than 10 minutes.

These fizzing galaxies are a child-safe chemical reaction that is so much fun to watch! When you add glitter and confetti you can see the stars shooting out from the center of the galaxies, just like in real galaxies!

The small pipets I recommend for this activity ensure that the little galaxies last a while. Or if you want a big bang, dump all the vinegar at once and watch it bubble! 

Disclaimer: As an Amazon Associate I earn from qualifying purchases. This means I get commissions for purchases made through links in this post at no extra cost to you. I do my best to only recommend products I have tried and would use again for these activities. 

Be aware that vinegar is a mild acid and can cause skin irritation. Make sure your child doesn’t touch their eyes or drink it undiluted.  Have a wet rag ready to dilute and wipe it from their skin if they touch the vinegar directly.

Supplies for the Fizzing Galaxies Toddler Activity

Fizzing Galaxies Toddler Science Activity Supplies

  • 16 oz Baking Soda
  • 1/2 cup water
  • Vinegar ( I recommend a gallon jug, just so you don’t run out by the time you get to all the galaxies.)
  • Sphere Ice Cube Mold (this is the one I have but there are many options)
  • Food Coloring
  • Optional: Pipets
  • Optional: Holographic Glitter
  • Optional: Confetti Stars
  • Optional: VO5 Kiwi Lime Shampoo. If you didn’t know this already, I have to tell you! This stuff makes the best bubbles! I always buy this instead of bubble bath, it’s cheaper and the bubbles are so much better! When you add this to the reaction of the galaxies and the vinegar, BOOM! It’s almost what you see when you make Elephant Toothpaste.

How To Make the Fizzing Galaxies

You’re going to want to work quickly when you make your mixture. The baking soda will not actually dissolve into the water so it will separate. The faster you can get the mixture into the mold the better!

fizzing galaxies

 Steps to Make the Fizzing Galaxies

1.     Take a 16 oz box of baking soda and combine with 1/2 cup of water. Mix together until you have a thick paste.

Disclaimer: you may want to consider having extra baking soda on hand. The first box will make enough to fill the 6 molds with a little paste left over. However, the mixture will settle and you may want to add extra paste to make perfect spheres.

2.    Once you’ve got your paste, separate into bowls for each color you would like to put in your galaxies. Add a generous amount of food coloring to each! They will look bright before they freeze but as the water naturally separates from the spheres, they will fade in color. 

Fizzing Galaxies mixture

3.     Add glitter and stars into the mixture. I recommend leaving the glitter in slightly globby streaks to add texture. It will also look awesome when it hits the vinegar!

I took a paintbrush and added extra glitter to the sides of the mold so that there were extra sparkles on the outside of the galaxies for that WOW! factor. 

Fizzing Galaxies glitter mold

4.     Spoon the paste into the two sides of the molds. You can either freeze them separately now or flip them together. If you flip them together now, keep the side with the hole on top.  Be aware that when you squish them together the top will lose a little volume. In order to make perfect spheres, you will need to spoon some extra mixture in there.

Honestly, it’s tedious to spatula or spoon mixture into the tiny hole. That’s why I don’t recommend using the holes to put in the full second half of the mold unless you don’t mind it taking a while. I personally love the look of the galaxies after a little mixture leaks out. It gives the balls those Saturn-like rings. 

If you freeze them separately you’ll need to bind them with some mixture after they’ve set and then let them set again. If you choose this route, spoon mixture into the side of the mold without the hold. Freeze this side for at least an hour. You can keep your remaining mixture at room temperature and then mix again when its time to pour it into the mold. 

Take out the half that is frozen and move those to the side of the mold with the holes. Add the remaining mixture into the hole-less side of the mold. If you squish them together now the frozen mixture will sink down into the un-frozen mixture. You can also wait for the 2nd half to freeze and then add a blob in between the two and freeze it a third time. 

5.      Freeze the mixture for a minimum of 2 hours. I prepare the girls’ activities the night before so an overnight freeze worked perfectly. When I tried to make these during the day an hour left them soft and I had extremely colorful fingers. 

Keep them frozen until you are ready for the reaction. 


Fizzing Galaxies Mold

6.      Give your child a bowl of vinegar and a pipette. Show them how to sprinkle vinegar over top of the galaxy and watch it fizz! The stars and glitter will unravel as the vinegar eats away at the galaxy. 

If they get bored of that (and haven’t already dumped the vinegar on the galaxies–or they have and there is still a little ball in their bowl) mix a tablespoon of V05 per cup of vinegar and watch the reaction explode! Be sure to have a towel, a bin, or mop ready!

This activity definitely counts as a sensory activity! Vinegar’s strong smell helps their olfactory senses. As the reaction occurs you can hear the fizzing of the galaxies for auditory stimulation.  And, as the stars shoot out from the galaxies, as they dissolve, or the bubbles fizz up, your child will be using their visual tracking skills. Way to go, mom or dad!

For more information on the importance of sensory activities, check out this post.

After the reactions you will either have galaxy vinegar with glitter and stars or a light foam your children can play with. My girls loved scooping the foam up with spoons and putting it in various containers. The fizzing galaxies truly kept them occupied for more than an hour!surprised

fizzing galaxies aftermath

I hope your kids enjoyed the fizzing galaxies as much as mine did! If you enjoyed this post and want more ideas, please subscribe and I’ll let you know when the next post comes out. Thanks for reading!



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Fizzing Galaxies Growing Up Goddesses
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Hi! I’m Katie. I’m a mom with two toddlers born 14 months apart. Growing Up Goddesses is about empowering toddlers and parents with educational printables, activities, and articles.
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