Using Probes to Test Water Quality

Testing water quality has become a fairly common activity for middle and high school science students. In most locations, students have the opportunity to gather water samples from locations near their schools and kits are available offering the resources necessary to perform several types of tests on the samples. The typical premis in water quality experiments is that water quality variables are related to the presence or absence of particular macroinvertebrates and other aquatic organisms. Simultaneous observation of water quality variables and aquatic organisms allow scientists (students) to establish such connections. Water quality projects involve students in investigations that can be related to many academic areas - biology, chemistry, social studies (government policy), and writing.

Here are three short videos to familiarize you with what students do in a water quality testing project. The first video provides a description of the basic equipment used in a probe-based data gathering task. The second video is a short interview with Lorraine O'Shea a middle school science teacher. Lorraine describes her experiences using both chemical and probe techniques in water quality projects. The final video takes you on an "eco-ed" field trip with middle school students.

I. Description of probe equipment

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II. Interview with experienced teacher

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III. Student use of probes

Here is a description of a student project. Middle school students from our community attended an "eco-ed" day at a nearby state park. Several tests of water quality and related observations of aquatic organisms were included. What made the water quality component unique was an effort to contrast older and newer methods for measuring important variables. Students measured pH, dissolved oxygen, and turbidity and gathered information on water flow and depth. They also collected and identified aquatic organisms. Students used chemical test kits and probes. They used weighted string and sonar. They used viewing tubes and an underwater camera. The consistency of data gathered with different methods could be compared. In addition to learning about how water quality influences the presence of biological organisms, students had an opportunity to contrast multiple methods for measuring the same variables.

Riffle Beetle Larva

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Vernier probes for the Palm

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