Introductory fermentation balloon module

Reference: Hellinger, Lisa, https://sites.google.com/site/sed695b4/projects/discrepant-events/fermentation---bewitched-balloons

teacher notes

student documents

career related resources

what materials are needed

  1. balloons - 1 per flask
  2. 1000 ml flasks - 2 each
  3. sugar
  4. salt 
  5. 400 ml warm water
  6. dry yeast - 2 packages (record the quantity in grams)
  7. print this data collection sheet

what are the steps

  1. Prepare 2 equal size small plastic bags - one with a package of yeast and the other with an equal amount of sugar-  label them both with the #1 
  2. Prepare 2 equal size small plastic bags - one with a package of yeast and the other with an equal amount of salt -  label them both with the #2
  3. Do not tell students what the bags contain
  4. Prepare 200 ml of warm water in each flask
  5. Ask a volunteer to help and have them pour the contents of both bags labeled one into one flask of warm water. Repeat with the bags labeled 2 in the second flask of warm water
  6. Students add 50 ml of warm water to each dry sample and stir
  7. Attach a balloon over the mouth of each flask
  8. Students can record a time lapse video of the results

break point: 45 minute lesson plan

Questions

 1.  Yeast cells are alive. What do they “eat" to get the energy they need to grow? What “waste   products" do yeast cells produce during fermentation?

2.  In this experiment you determined how fast Baker's yeast ferments sugar by measuring how much   carbon dioxide was produced. How else could you measure the rate of the fermentation reaction?

3.  How long did it take before the yeast started to make carbon dioxide from the sugar (“lag time")?   Why do you think the reaction did not start right away?

4.  Once fermentation began, the carbon dioxide that was produced pushed most of the air out of the   reaction bottle. How could yeast cells live without oxygen?

5.  What do you think would happen if you added more or less sugar to the reaction bottle at the start   of the experiment? How could you test your hypotheses?

6.  Why did you add warm water to the reaction bottle? What do you think would happen if you used   cold water? How could you find out what water temperature makes yeast ferment sugar at the   fastest rate?

7.  What else do you think could make the yeast fermentation reaction go faster? What could slow it   down? Think of experiments that could help you find out.