Al Bashaer International School
American Division
Science Department
Biology
Grade 10
Name _____________________________ Class __________________ Date __________________
Fermentation Lab
Purpose: To observe the process of fermentation in a living organism, yeast (Saccharomyces).
Materials:
125 ml Erlenmeyer Flask (3) Yeast (Saccharomyces) Hot Plate /Thermometer
7 inch Balloon (3) Scale Piece of String
Sugar Ruler Pencil/Pen/ or China Marker
Procedure:
1) Gather the needed materials. Label the 125ml conical flasks 1, 2, and 3. Put your group’s name on each to
identify your own flasks.
2) Pre-stretch the balloons. Do this by stretching them and blowing them up and letting out the air.
3) Set up the following flasks using the procedure for each flask.
Flask #1: 75 ml of warm water (40o C)
6.5 grams of sugar
Put the pre-stretched balloon immediately over the top of the flask
Flask #2: 75 ml of warm water (40o C)
1 gram of yeast
Put the pre-stretched balloon immediately over the top of the flask
Flask #3: 75 ml of warm water (40o C)
6.5 grams of sugar
1 gram of yeast
Put the pre-stretched balloon immediately over the top of the flask
4) Gently stir the flask to mix the materials in each flask. Allow the flasks to sit for some time.
5) Observe the change in the size of the balloon for each flask and record in the table.
1
6) Transfer the balloons on to a flask of lime water  turn turbid in presence of carbon dioxide and record in
the table.
8) Clean up your lab supplies. Make sure to clean out all flasks thoroughly.
Data/Results:
Flask
#
Contents
1
Sugar & Water
2
Yeast & Water
3
Sugar, Yeast &
Water
Change in balloon size
Scientific method
1) Question
2) Hypothesis
3) Experiment
4) Observation/ Results
5) Conclusion
2
Change in lime water
Discussion:
1) What process was observed in this lab?
2) What gas was produced in this process? What observation was seen to show this production?
3) What is the overall equation of cellular respiration? Circle the reactants, Place a box around the products.
4) Which flask or flasks had no observable gas production? Why is this so?
5) Which flask produced the largest volume of gas? Why might this be so?
6) What are some observable indicators that a chemical reaction was taking place inside some of the flasks?
(Name two)
7) How are photosynthesis and cellular respiration connected in a biochemical pathway?
3