Biology - HOT Science Lab

Student
3. Using the forceps, dip a filter paper disk into the beaker containing the solution of
activated yeast. Keep the disk in the solution for 4 seconds, and then remove it.
4. Place the disk on a paper towel for 4 seconds to remove any excess liquid.
5. Using the forceps, transfer the filter paper disk to the bottom of a rubber stopper.
Note: The yeast solution contains the catalase enzyme and when the enzyme soaked
disk comes into contact with hydrogen peroxide, the reaction results in the formation of
oxygen bubbles.
6. Insert the stopper into one of the test tubes and quickly invert the test tube. Have one
person in your group measure how long it takes for the bubbles to carry the disk to the
top of the test tube. Record the time in a data table similar to the one shown below.
7. Repeat steps 2-5 until you have a minimum of three trials for each peroxide solution.
8. Calculate the average rising time for each of the peroxide solutions. Record this
information in your data table.
9. Construct a graph plotting the concentration of hydrogen peroxide on the x-axis
(independent variable) and rising time on the y-axis (dependent variable).
Observations/Data:
Table: Rising Time
Beaker Trial 1 Trial 2 Trial 3 Average
0% Peroxide
25% Peroxide
50% Peroxide
75% Peroxide
100% Peroxide
Data Analysis:
Construct and analyze a graph from your table.
Results/Conclusions:
1. Suppose you had placed a filter paper disk in a 30% peroxide solution. Using your graph,
predict how long it would take this disk to rise to the top.
2. In a paragraph describe how the concentration of peroxide affects the breakdown rate of
hydrogen peroxide. Use the results of this experiment to justify your answer.
3. In a paragraph explain why your hypothesis was or was not supported.
4. Complete a formal laboratory report.
Extension:
1. Choose another factor to test. Develop a new problem statement and design a new
experiment to test for this factor. Record all parts of the lab (from the parts of a lab) in
your journal. Present your findings to the class.
2. Make sure to identify the test (independent) variable, responding (dependent) variable,
controls, and constants.
Biology HSL Page 227
Curriculum and Instruction