Yeast Fermentation Lab

Problem:  To what extent does the amount of glucose affect the rate of yeast fermentation?

Background:  As yeast ferment sugars, they release a by product CO2.  The rate of fermentation can be measured by capturing the gases released and measuring them.  Fermentation does not depend on oxygen availability, so balloons can be placed over tubes containing yeast and sugar.

Hypotheses:

 

Materials:  4 test tubes, glucose, distilled water, balloons, and masking tape

Procedures:

  1. Place a small amount of yeast (equal in all tubes) in the test tubes (1 mm at bottom).

  2. Place the same amount of water in 4 test tubes (about 1/2 full).

  3. Place different amounts of glucose in each test tube:  tube 1- no glucose solution, tube 2 - 1 drop of glucose solution, tube 3 - 2 drops of glucose solution, tube 4 - 3 drops of glucose solution.  

  4. Place a balloon over the top of the tube.

  5. Tightly tape the balloon onto the tube so it will not blow off.

  6. Measure the results of your test by measuring the balloon height in cm

  7. Graph the results.

Data Tables:

Glucose Solution # Drops

Balloon Height (cm)

0 drops  
1 drop  
2 drops  
3 drops  

Bar Graph: (be sure to include the title, the Y-axis units, and the X-axis units)

         
         
         
         
         
         
         
         
         
         
   0 drops 1 drop 2 drops 3 drops

Conclusion:

1) Did your data support your hypothesis? Explain.

2) What went well with your experiment?

3) What did not go so well?

4) What new questions (problems) could be studied in a future lab?

5) What did you learn from this lab activity?