cartoon robot



In this yeast and sugar science project, you can watch yeast feed on sugar to fill a balloon with carbon dioxide gas. It’s a fun experiment for kids that’s made with household, everyday materials.


  • Sugar, 2 tablespoons
  • Active dry yeast, 1 packet or 2 1/4 tablespoons
  • Balloon
  • Warm water (40.5-46 degrees C)
  • Mixing bowl and funnel
  • Bottle that you can fit a balloon over


  • Mix the yeast and sugar into the warm water and stir.
  • Once it all dissolves, pour the mixture into the bottle and cover the bottle with the balloon.
  • After a few minutes you’ll be amazed by the balloon filling with gas!
  • Once the bottle fills up with bubbles, you can the whole yeast sugar experiment to the sink.

Spark Creative Learning!

As the yeast feeds on the sugar, it produces carbon dioxide. With no place to go but up, this gas slowly fills the balloon. A very similar process happens as bread rises. Carbon dioxide from yeast fills thousands of balloon-like bubbles in the dough. Once the bread has baked, this is what gives the loaf its bubbly, airy texture.

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