In a previous lesson, I began instruction with a vial of water and asked students how they could determine if the water was safe to drink. I utilize this same question to start my lesson on drinking water. This time around, students have a broader knowledge base on which to draw to construct their answers. I ask students to consider which tests they have used at the stream site would be most important to use to test drinking water. I ask students to share their thinking and record the test names on the whiteboard.
Next, I guide students through a review of our local drinking water quality report. The report contains many new terms, so I review with the students the types of tests conducted to determine the quality of our drinking water. Students will be familiar with the tests for pH and biological contaminants from our previous stream monitoring work. Collaboratively, we review the data and what it means to our community.
Drinking water quality reports can be found on the websites of most cities and counties. A link to our local drinking water report can be found here.
A video of a student group discussion can be found here.
After the students have developed a basic understanding of the water quality report, I ask them to engage in an independent reflection on water quality. I ask them to use information from the water quality report to complete a chart with key test results and then to use these results to form a personal opinion on water quality. It is a key objective that students use test results / data to justify their conclusions. I ask students to record their thinking on the drinking water quality record sheet.
An example of one student's completed drinking water quality record sheet can be found here.
I guide students in a brief discussion of their conclusions. I ask each students to share their overall judgment of water quality from the five point scale at the bottom of their record sheet. I recreate this scale on the whiteboard and tally each student's opinion on the scale. This gives our class and overall judgment about our drinking water quality.
To assess student understanding of the concepts in today's lesson, I ask students to complete the drinking water exit ticket. I use this to assess whether students have justified their opinion using test data and whether they were able to follow our class discussion.