AP Biology- Fermentation Lab
Purpose: To observe the process of fermentation in a living organism, yeast (Saccharomyces).
Materials:
250 ml Erlenmeyer Flask (4)
7 inch Balloon (4)
Apple Cider
Calculator
Yeast (Saccharomyces)
Scale
Sugar
Funnel
Hot Plate or Microwave
Piece of String
Ruler
Pencil/Pen/or Marker
Procedure- Day #1:
1) Gather the needed materials. Label the 250ml Erlenmeyer flasks 1, 2, 3, and 4. Put your groups
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. Make sure to be accurate in your
measurements.
Flask #1:
150 ml of warm water
13 grams of sugar
Put the pre-stretched balloon immediately over the top of the flask
Flask #2:
150 ml of warm water
2 grams of yeast
Put the pre-stretched balloon immediately over the top of the flask
Flask #3:
150 ml of warm water
13 grams of sugar
2 grams of yeast
Put the pre-stretched balloon immediately over the top of the flask
Flask #4:
150 ml of apple cider
2 grams 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 24 hours.
Predict what will happen in each flask based on the contents? Defend your prediction.
Day 2
5) Use a piece of string to measure the circumference of each balloon. If the balloon does not look
noticeably different from the start of the experiment, calculate the circumference of the balloon as zero.
Complete the data table.
6) Use the circumference of the balloon and the following equations to calculate the diameter of the
balloon. Complete the data table
C = 2r
d = 2r
7) Calculate the volume of gas produced using the following equation. Complete the data table.
Volume of Gas Produced =
4.187 x (diameter of balloon in cm / 2)3
Data/Results:
Flask #
Contents
Circumference of
Balloon (cm)
Diameter of
Balloon (cm)
Volume of Gas
Produced (cm3)
** round all answers to 2 decimal places
Discussion:
1) What process was observed in this lab? Describe the process using details.
Describe what was happening in each flask (using reactants and products formed)
Flask #1
Flask #2
Flask #3
Flask #4
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?
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? Explain.
7) How are photosynthesis and cellular respiration connected in a biochemical pathway?
Summarize what you have learned by doing this lab: