I conducted a yeast experiment with my boys a few weeks ago. My oldest son is 4 and he loves science experiments. Technically, this wasn't a true science experiment because we didn't set up a control, but oh well, we had fun anyway.
Our experiment was about what types of fuel that bread baking yeast will produce the most carbon dioxide consuming. We had 5 plastic bottles and chose 5 fuel sources; sugar, honey, molasses, corn syrup, and all purpose flour.
Into each plastic bottle we poured 1 tsp. of yeast, 1 TBS. fuel, and 1/4 cup warm water.
We secured a balloon onto the top of each bottle to capture carbon dioxide.
We labeled the bottles as we went.
Within 5 minutes of setting up, the sugar bottle was in the lead.
At the 15 minute mark I noticed that some of the balloons had teeny tiny holes in the stem portion of the balloons. I used rubber bands to seal off the stems.
I took a picture of the bottles after 30 minutes,.....
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| 1/2 hour |
... At 1 hour,...
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| 1 hour |
... And at 3 hours.
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| 3 hours |
The next day I blew up the balloons for the children to play with. We discovered that one of the balloons had a teeny tiny hole on the top of the balloon. I didn't know which bottle it had come off. My first thought was that the holey balloon had been on the bottle with flour. I really had expected the flour balloon to do better than it did.
The next day I ran the experiment again, with a bottle with flour as fuel, and a bottle with sugar to act as a control.
After 4 hours,....
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| 4 hours |
There you have it folks, yeast really likes simple carbohydrates.
Bread baking yeast produced about the same amount of carbon dioxide with each of the sweeteners that we tried. There didn't appear to be any significant difference between using sugar, honey, molasses, or corn syrup as fuel. Sugar had a little head start, but after an hour the rest caught up.
Let us know how we could improve this experiment! If you have any ideas tell us in the comment section!