When people and animals breath their bodies take oxygen into the lungs where it is passed into the blood. This is called respiration. There is another kind of respiration that goes on inside living organisms and that is called cellular respiration. During cellular respiration cells convert oxygen to carbon dioxide and water during a chemical reaction that happens inside the cell.
Yeast is a single cell organism that metabolized sugar and turns it into carbon dioxide and water. In this experiment you will be able to “see” the colorless, odorless gas that is carbon dioxide. You will know it is present because it will fill a balloon.
What You Need:
- Empty Water Bottle
- Warm Water
- 1 tsp Sugar
Put one packet of dry yeast into an empty liter soda bottle. Add about an inch of warm water to the yeast. Now add 1 tsp of sugar. Swirl this mixture around a little bit. Blow up a balloon and then let the air out again just to get it stretched a little. Now take the balloon and stretch its opening over the mouth of the water bottle. Check on the balloon every five minutes for the next half our or so. What happens to the balloon?
Science Experiment Idea: Try this experiment with three different soda bottles. Add the yeast to each one. Make your variable the substance you add to the yeast. Put water in bottle #1, soda in bottle #2, diet soda in bottle #3. You could try different kinds of juice, milk, etc. Which substance do you think will blow up the balloon the best? Why?
Websites, Activities, Printables:
- Exploratorium: Yeast-Air Balloon
- Science Bob: Blow Up a Balloon With Yeast
- The Science of Yeast
- ZOOM Science Rocks: Yeast
Science in Context: Cell Respiration is a database you can use in any IndyPL Library Branch or at home. Login using your IndyPL library card number. The Science in Context database will show you articles, images and videos to help you learn about cell respiration.
You can also ask a math and science expert for homework help by calling the Ask Rose Homework Hotline. They provide FREE math and science homework help to Indiana students in grades 6-12.
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