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Science - Earth Science
Standard 4 Objective 2
1 class periods of 70 minutes each
In this exercise, students will measure the temperature and dissolved oxygen of a stream (or use their findings from the activity What's in the Water?) and discuss what this information can tell us about possible pollution problems.
* For information on equipment for loan or for purchase, contact USU Water Quality Extension at (435) 797-2580 or www.extension.usu.edu/waterquality
To relate the physical and chemical properties of water to a water pollution issue.
During this activity students will investigate two properties of water in a stream the temperature and the concentration of dissolved oxygen in the water. Students will explore how natural influences, human activities and pollution may cause these parameters to change. They will compare their results to Utah's water quality standards and investigate possible ways to restore a polluted stream to healthier conditions.
Temperature and oxygen were chosen for this activity because they are easy to measure, the causes of change are both varied and easy to understand, and also the two properties are related to each other. Fish and other animals living in water can be harmed by high temperatures and low oxygen concentrations. As water gets warmer the "saturation concentration" for oxygen gets lower in other words the warmer the water, the less oxygen it can hold. Therefore, when water temperatures increase, fish are often hit with a double whammy of low oxygen as well. For more information about dissolved oxygen or temperature, see the Utah Stream Team Manual or the Further Discussion questions.
This lesson plan is designed to follow the activity What's in the Water?, during which the students measure several abiotic factors in a stream, or the lesson can be conducted as a stand alone.
NOTE: If you have already done the activity What's in the Water? skip to field activity step five.
NOTE: these measurements must be taken at the stream site, as storing them will give an inaccurate measurement.
Be sure to point out that factors such as elevation and salt content will affect the ability water has to hold oxygen. At higher elevation, water holds less oxygen and salty water holds less oxygen.
Lesson plan authors: Andree Walker and Nancy Mesner (Utah State University Water Quality Extension)
This curriculum was made possible through funding from the Environmental Protection Agency, the United States Department of Agriculture, Cooperative State Research, Education, and Extension Service, the Utah Division of Wildlife Resources, and Utah State University Extension.
Additional resources can be found on the USU Stream Side Science 9th Grade Curriculum web page.