Science JunctionLesson 3

 Design an experiment to test the effects of increases or decreases in dissolved oxygen levels on aquatic plants and animals.

Students will be able to:  Note: Students should be working in groups of two or three to complete this experiment.

Dissolved oxygen test kit (Chemical)
assorted glassware
air pumps and tubing
assorted plants and animals

Note: Students will provide a detailed list of materials as they design their experiments.

Question to be investigated:
1. How do increases or decreases in dissolved oxygen levels effect the breathing rate of goldfish?
2. How does an increase or a decrease in dissolved oxygen levels effect the biodiversity of
a pond water sample?
3. How do dissolved oxygen levels effect the growth of algae or plants?
4. Can certain macroinvertebrates survive at low levels of dissolved oxygen?

Note: Working with a partner, students should develop their own question to be investigated.


Hypothesis related to the question to be investigated:
Working with a partner, write a hypothesis related to the experimental question.
Remember, a hypothesis is a tentative solution to the problem.


Note: Safety goggles and aprons should be worn at all times during this lab activity.

Working with a partner:
Develop a step by step plan on how the experiment will be carried out. Make sure to include a time line.

Set up the experiment:
This is a trial run. At this time, any problems which may be encountered in the experimental design may be corrected.

Data Collection:
The data collected should be presented in table form.

Analyze the data collected:


Written Report:
Write a brief report to explain the experiment. Does the data collected support the hypothesis? Why or why not? Explain any sources of error which may have interfered with the data collection and the
final results.
Oral Presentation:
This should be a brief presentation of the written report.

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©1998 April J. Cleveland for Science Junction, NC State University. All rights reserved.
page design by Lisa Leonor Grable and April J. Cleveland 
Last Modified: 6/8/98
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