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yeast and sugar substitutes
Posted: Wed Apr 22, 2015 10:12 pm
by jhenderson
My son is in 5th grade and wants to be a chef. We were excited about this project but are getting no results. There is no gas displacement. We are measuring, the cap is air tight. I am wondering if the diameter of our tube is too small. I am getting discouraged- running out of time.
Thanks,
Jane and Owen
Re: yeast and sugar substitutes
Posted: Thu Apr 23, 2015 2:28 pm
by skuzniewski
Jane and Owen,
I am not sure what your method was but I think you are supposed to have water in the tubing because the yeast needs to the water to produce the carbon dioxide.
If it might help, here 's a simple write-up report on the same objective of the experiment:
http://biosurvey.ou.edu/oas/06/paper/malatinsky.pdf
The gas bubbled and so the increase in height of the mixture in the test tube.
Could any one of these might also be possible?
1. The yeast might not viable and so no bubbles. This could be if the yeast is too old or if the yeast pack was left open for a long time and so the yeast dried up.
2. Too hot or too cold water. Too hot can kill the yeast and too cold is not feasible for the chemical reaction to proceed to produce the carbon dioxide. I will recommend warm, tap water.
2. Too much sugar. Too much sugar can kill the yeast.
Good luck!
-Sally Kuzniewski