Can you inflate a balloon with yeast? You sure can! Let's learn how with this simple and fun science experiment for kids.
When you think of yeast, you probably think of baking. But this little ingredient makes for some great science experiments as well!
This yeast balloon experiment is:
- A fun STEM activity for kids of all ages.
- Simple to do with ingredients you probably already have!
- Quick, easy and fun.
Yeast Balloon Experiment - Step by Step
Start by filling a large mixing bowl with warm water. It only needs to be lukewarm - not very hot.
Next mix instant yeast, sugar, and warm water together in a glass bottle or flask with a narrow neck (like this Erlenmeyer Flask). If you don't have one, you can use any bottle or container with a narrow neck. Even a disposable water bottle will work in a pinch. You need to be able to stretch the balloon over the opening!
Place the glass bottle into the bowl of warm water to keep it warm. Stretch the balloon over the opening of the bottle.
Sit back and watch what happens! You should see the balloon slowly begin to inflate. How long does it take for the balloon to inflate?
What did we learn?
Yeast is a living organism! And it loves to eat sugar. As the yeast consumes the sugar in your mixture, it converts the sugar into alcohol and carbon dioxide gas. The balloon inflates from the carbon dioxide gas!
This is the same process that is at work when you bake bread or other baked goods with yeast. The yeast consumes sugar, and releases carbon dioxide, which causes your dough to rise. Cool, huh?
Expand the Experiment!
Try the experiment a few more times, with varying amounts of sugar and yeast. What combination inflates the balloon to the largest size? Why do you think that happens?
Try again using cold water instead of warm water. Does the balloon still inflate? Why or why not?
More STEM Activities for Kids
If you love this yeast balloon experiment, check out these other fun activities for kids:
- Microwave Ivory Soap - An Easy Experiment!
- STEM Activities for Elementary Kids
- Best Science Experiments for Kids
Yeast Balloon Experiment
- 2 tbsp instant dried yeast
- 1 tbsp sugar
- 2 tbsp warm water
- additional warm water
- large mixing bowl
- glass flask or bottle with a narrow neck
Fill a large mixing bowl with warm water.
Mix the instant yeast, sugar, and 2 tbsp warm water together in the glass bottle or flask.
Place the glass bottle into the bowl of warm water to keep it warm.
Stretch the balloon over the opening of the bottle. Wait and watch the balloon inflate!
The water should be warm enough to activate the yeast, but does not need to be very hot.
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