Expanding Balloons! Simple Yet Spectacular Science Experiment!

Expanding Balloons! Simple Yet Spectacular Science Experiment!


Making carbon dioxide and filling up a balloon with it! Ok, yes yes, you could just blow up the balloon but this is a thousand times more fun and they get to see the reaction between an acid and a base… This always gets a fun reaction and I love doing this one with the kids!



Expanding Balloons!


What you need:

Empty plastic water bottle
Balloon (or more because it’s hard to just do one)
Baking soda
Funnel to make life easier


  • Fill empty water bottle half full with vinegar
  • Put the tip of the funnel inside the balloon and add about 2 TBS of baking soda inside the balloon.
  • Wrap the end of the balloon around the opening of the water bottle, making sure you don’t tip any of the baking soda into the vinegar.


  • Have the child then tip the balloon upright making sure the baking soda dumps into the vinegar.
  • Watch the reaction of baking soda and vinegar when mixed! It creates a gas which then goes up into the balloon causing the balloon to expand!


What is going on – This would be considered an acid/base reaction – the baking soda being the base and the vinegar being the acid. When you add them together they create carbon dioxide and that gas starts to expand and jump around, it starts to take over the entire space which is why it expands into the balloon and therefore filling the balloon up!


The balloon won’t really “float” and they deflate pretty quickly so make sure you have more balloons, baking soda and vinegar on hand so you can do more because this is just super fun. My two kids decided to have a race to see whose balloon would fill up the quickest. Have fun with it!



Speak Your Mind