Blow Up a Balloon with Yeast

We learned what every living thing that God created needs to live. Water, food, and air. Like people, yeast needs energy (food) to be active, so we gave the yeast sugar to eat. We talked about the yeast and that it comes from a plant. As the yeast eats the sugar, it releases a gas called carbon dioxide. The gas fills the bottle and then fills the balloon as more gas is created. The kids are familiar with yeast because we make homemade bread. They learned that the yeast being “bubbly” gives off carbon dioxide, the same gas that your body produces when you breathe, and the gas inflates the balloon. We discussed how our lungs worked and compared the balloon to our lungs.

What you need:

1. A packet of yeast

2. Plastic soda bottle

3. 1 teaspoon of sugar

4. Some warm water

5. A small balloon

6. A funnel

7. A ruler and marker (to measure how high the yeast expands)

8. A large bowl of warm water

Right away the balloon blow up just a little but, wait..

Mom," I didn't see it blow up so how do I know you didn't blow it up?" (Bug needed proof) So she had me try another balloon and she kept her hand on the balloon the whole time. She wasn't going to miss it a second time.

Then the blue balloon came off and we had to try the yellow balloon again.

After 20 minutes the balloon was filled. We kept this balloon going for several hours and when it would deflate one of the kids who shake it and it would rise again. "The yeast must of eaten all it could," according to Little Man because it went flat.

What to do:

1. Fill the bottle up with about 2" of warm water.

2. Add all of the yeast packet and swirl the bottle a few seconds.

3. Add the sugar and swirl it around some more.

4. Blow up the balloon a few times to stretch it out then place the neck of the balloon over the neck of the bottle.

5. Set the plastic bottle in the bowl with the water.

6. Let the bottle sit in a warm place for about 20 minutes

Some questions to ask the kids. If you want to further the experiment you can try different types of food for the yeast and cold water.

1. Does room temperature affect how much gas is created by the yeast?

2. Does the size of the container affect how much gas is created?

3. What water/room temperature helps the yeast create the most gas?

4. What helps the yeast create the most gas? (try sugar, syrup, honey, and no food)

Have fun this was a fun experiment that the kids enjoyed. Grab you supplies this is an easy one.