Name _____________________________ Period ___________________ Date __________________
QUICK LAB—DESIGN YOUR OWN
Fermentation
Teacher Notes
TIME 20–30 minutes
Purpose Measure the amount of fermentation in various beverages
LAB MANAGEMENT
 Be
sure to use fresh yeast. Check the expiration date.
 Students may be interested in testing diet beverages that contain no sugar.
 Have students stretch the balloons before use so they inflate more easily.
 Students can use duct tape to create a tight seal.
 Students should measure the circumference of the balloon as a measure of
fermentation.
EXPECTED RESULTS
Beverages that contain the most sugar will yield the most carbon dioxide and the
most inflated balloons.
ANSWERS
Analyze and Conclude
1. independent variable: type or temperature of beverage; dependent variable:
inflations of balloon indicating the amount of carbon dioxide produced;
constants: amount of beverage and yeast, size of balloon
2. The type of beverage affected how much carbon dioxide was produced
because different beverages have different amounts of sugar. A higher sugar
concentration should increase the rate of fermentation.
3. inconsistent methods, poorly controlled constants, random error (for example,
different yeast activity, balloon rubber differences)
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
QuickLab—Design Your Own
1
Cells and Energy
Section 6: Fermentation
Name _____________________________ Period ___________________ Date __________________
QUICK LAB—DESIGN YOUR OWN
Fermentation
One waste product of alcoholic fermentation is carbon dioxide. In this lab you will
determine which beverage causes yeast to undergo a higher rate of fermentation.
PROBLEM
What factors affect the rate of fermentation in yeast?
MATERIALS
 2
empty plastic bottles
 1 package of yeast
 2 100-mL graduated cylinders
 2 250-mL beakers
 2 beverages
 2 round balloons
 30 cm string
 metric ruler
PROCEDURE
1. Write an operational definition for the dependent variable that you will use to
measure the rate of fermentation.
2. Develop a technique using a balloon to measure fermentation rate.
3. Design your experiment. Have your teacher approve your experimental design.
Write your experimental procedure and conduct your experiment.
4. Construct a data table to record your data. Construct a graph to display your
data.
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
QuickLab—Design Your Own
2
Cells and Energy
Section 6: Fermentation
Name _____________________________ Period ___________________ Date __________________
Fermentation continued
ANALYZE AND CONCLUDE
1. Identify What are the independent variable, dependent variable, and
constants?
_______________________________________________________________
_______________________________________________________________
2. Analyze How did the independent variable affect the rate of fermentation?
Why?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
3. Experimental Design Identify possible reasons for any inconsistent results
you observed.
_______________________________________________________________
© Houghton Mifflin Harcourt Publishing Company
Holt McDougal Biology
QuickLab—Design Your Own
3
Cells and Energy
Section 6: Fermentation