Graphing our Test Results

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Objective

SWBAT visually display the results of water quality tests on a graph and use the graph to make judgments about water quality.

Big Idea

Data can be represented visually using a graph. We can use the results of water quality tests to make judgments about overall water quality.

Introduction

10 minutes

To begin the lesson, I ask students to review the results of their tests that they conducted in the previous lesson at the stream site. I ask students to check with their group members to make sure that each student has accurately recorded the data and has labeled each result with the appropriate unit of measure. This data review serves two purposes. First, the review of data activates shared prior knowledge that was constructed on our stream monitoring trip. Second, sharing data with the team prior to the lesson allows each student to check their results for accuracy.

Independent Practice

30 minutes

I ask students to use the graphing worksheet to record and visually represent their data from the stream monitoring trip. There is a separate graph for each water quality test. I encourage students to work together with their classmates to ensure accuracy in the students' graphs.

A sample of a student's completed graph can be found here. The student sample shows a graph that was completed with four month's worth of stream monitoring data. This lesson serves as the first step in completing such a product. I ask students to keep their graph in their science journal and we add to the graph after our monthly stream monitoring trips.

A video of a student explaining significant results can be found here. This student is comparing his results to those recorded by my class last year.

Class Discussion

20 minutes

After the students have successfully graphed the data from our stream monitoring trip, I lead a class discussion on what this data can tell us about water quality. It is common to have data from one test contrast with the data from another test. For example, in the attached graph sample, the test results from the dissolved oxygen and water temperature tests are in the expected range for water with good quality,  but the test results for pH and nitrates indicate poor water quality. This contradictory data is difficult for students to understand, so I guide them in a discussion of how to use several data points to make a judgment about overall water quality.

Next, I provide students with time to record their thinking on the graph questions record sheet. A sample of a completed record sheet can be found here