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Yeast Balloon Experiment

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Check out this super cool experiment that uses the expanding power of yeast to inflate a balloon! You and your kids will love doing this Yeast Balloon Experiment together.

Get more amazing Balloon Science Experiments here!

Yeast in a bottle inflates a balloon

This is a mind-blowing (and balloon blowing) way to learn about the common reaction of yeast, sugar, and water!

Table of Contents

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  • Yeast Balloon Experiment
    • Supplies Needed:
    • How to Inflate a Balloon With Yeast
  • Step 1: Pour Warm Water Into a Plastic Bottle
  • Step 2: Add Some Yeast Into The Bottle
  • Step 3: Add Some Sugar
  • Step 4: Attach The Balloon to The Bottle
  • Step 5: Wait Patiently For The Reaction to Inflate The Balloon
  • Yeast Balloon Experiment Conclusion
  • More Fun Experiments For Kids:

Yeast Balloon Experiment

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Supplies Needed:

  • Yeast
  • A Plastic Bottle
  • Sugar
  • Warm Water
  • A Balloon
Materials to make a balloon inflate with yeast

How to Inflate a Balloon With Yeast

  1. Fill a plastic bottle with about 1 inch of warm water.
  2. Pour in about 1 tablespoon of yeast and gently shake the bottle up a little bit.
  3. Add a teaspoon of sugar and swirl the bottle around a little more.
  4. Slide the neck of the balloon over the opening of the bottle.
  5. Let the yeast work its magic for about 15-20 minutes. The balloon should slowly start to inflate!

Step 1: Pour Warm Water Into a Plastic Bottle

I prefer to use a clear plastic bottle for this so that you can see the reaction of the rising yeast inside, but you really can use any type of small empty water bottle for this.

The important part is to pour enough warm water into the bottle so that that the water is about an inch deep inside the bottle.

Pour warm water into a bottle

If you bake with yeast often, then you will already know that the water needs to be warm, but not too warm or it will kill the yeast (I had to learn this from my wife who does the baking in our family).

Step 2: Add Some Yeast Into The Bottle

If you have the small little packets of yeast, you can dump one of those into the bottle, or you can measure and pour about 1 tablespoon of yeast from a large packet of yeast.

Add some yeast to the bottle

Using a funnel will make this a little easier and a little less messy to get the yeast inside the bottle.

Step 3: Add Some Sugar

Measure and pour about 1 teaspoon of sugar into your bottle of yeast and warm water. Again, using a funnel will help you get less sugar on the counter and more sugar into the bottle.

Add a spoon of sugar to the bottle

Step 4: Attach The Balloon to The Bottle

Quickly, but carefully connect a large balloon to the opening of the bottle. It may help to inflate and then deflate the balloon first just to stretch it out a little bit.

Connect the balloon to the bottle

Then slide the mouth of the balloon over the opening of the bottle. Make sure the balloon is snug and sealed onto the bottle to prevent any air from escaping between the bottle and the balloon.

Give the bottle a little swirl or shake to mix the warm water, yeast, and sugar together. This should start the classic yeast reaction that we need for this experiment!

Shake the yeast, water, and sugar in the bottle

Step 5: Wait Patiently For The Reaction to Inflate The Balloon

The hardest part of this experiment is waiting 15-20 minutes for the reaction to happen and inflate the balloon…but I promise it will be worth it!

So set the balloon and bottle in a safe and secure place, go grab a snack and come back in a few minutes to check on it.

Set the experiment down and wait a few minutes

You can also try doing what I did and setting up your phone or camera for a time-lapse video of the reaction. It’s super fun to go back and watch the reaction inflate the balloon with the time-lapse.

After a good 15 or 20 minutes, the yeast, water and sugar should have reacted and expanded inside the bottle, and the balloon will inflated too!

The yeast reaction will inflate the balloon

Yeast Balloon Experiment Conclusion

The science behind this yeast balloon experiment is related to the same reason yeast is used in many bread, dough, and baking recipes!

Yeast is a single-celled organism described as a “sugar-eating fungus”. Yeast needs food, warmth, and moisture to thrive and grow.

As the yeast grows and converts the sugar into energy, it releases Carbon Dioxide gas in a process called fermentation.

The tiny little carbon dioxide (CO2) gas bubbles get trapped in bread dough as it bakes and is what makes bread so soft and spongy!

Now in our experiment, the warm water in the bottle provides warmth and moisture for the yeast, while the sugar provides the food for the yeast to grow and expand.

The addition of carbon dioxide in the bottle increases the air pressure in the bottle, which pushes air into the balloon and inflates it!

This Baking Soda and Vinegar Balloon Experiment is also another fun way to inflate a balloon if can’t find any yeast in your kitchen cabinets!

PIN THIS EXPERIMENT FOR LATER

Carbon dioxide from the yeast inflates the balloon

More Fun Experiments For Kids:

  • Dancing Grapes Experiment
  • How to Make a Bottle Gun
  • Cloud in a Bottle Experiment With Rubbing Alcohol

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Hi! I'm Taylor - a former broadcast meteorologist, and daddy of three little girls. You'll most likely find me in the great outdoors, checking the weather or exploring the fascinating world of science.

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