Fun with Fungus

Chemistry

Things You Will Need
• Soda bottle
• 2 teaspoons sugar
• 1 package powdered yeast
• 9-inch balloon
• Warm water
• Funnel

Do This

1. Pour 1 package of powdered yeast into a dry empty soda bottle.
2. Fill the bottle one-half full with warm (not hot) water.
3. Add 2 teaspoons of sugar to the yeast and water.
4. Place your thumb over the mouth of the bottle and shake to mix the contents.
5. Stretch the balloon mouth over the mouth of the bottle.
6. Observe periodically over the next 3 hours.

What Should Have Happened

Bubbles of gas will start forming and gradually inflate the balloon. Yeast is a living fungus that digests sugars and starches to produce energy. In this process, carbon dioxide gas is formed and released. The carbon dioxide gas collects in the balloon and causes it to inflate.