by Liz LaRosa
Objectives:
to determine the best conditions to grow yeast
to view gas production by yeast
to record observations and measurements.
to create a line graph.
Procedure:
Label your flask with your assigned group letter: A, B, C, D, or E.
For each Flask:
A - 5 mL sugar, 3 mL dry yeast,
B - 15 mL sugar, 3 mL dry yeast
C - 15 mL sugar, 5 mL salt, 3 mL dry yeast
D - 5 mL salt, 3 mL yeast
E - 15mL sugar, 5 mL salt
Fill the flask with 100mL of warm water
Place balloon over top of flask and rubber stopper (with one hole) tightly
Swirl flask to mix contents
Record observations in Table 1.
(Due to 45 min class, flasks were left overnight)
Measure the height of the balloon from the top of the stopper to the top of the balloon and record in Table 1.
Data:
Table 1 : Observations and Measurements of Balloon height in cm
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Figure 1: Graph of Balloon Height in cm
Make a full page line graph in your lab notebook.
X-axis Periods 1-6, Y-axis Height in cm.
Key: Flasks A-E with point protectors.
5 lines on line graph.
Analysis:
Compare what happened to each of the balloons for flasks A through E.
Why did we use warm water instead of cold water?
What flask(s) had the Most CO2 production? Least? How do you know? Be sure to describe WHY!
Describe what happened using the following terms : yeast, warm water, sugar, salt, and carbon dioxide.
Was there anything besides CO2 produced in the flask? What was it?
Conclusion:
2-3 sentences on what you learned in lab
Please note: this lab has been modified from its
original source: "Exploring Life Science" by Prentice Hall.
