On the first lab day, students assemble into their lab groups and perform pH tests on all of their chosen samples and on the control. This simple testing serves to monitor their laboratory ability and group dynamics. Have the students do a variety of different pH tests, using litmus paper or other pH papers, pH indicator chemicals, and a pH meter. After this preliminary testing is completed, share with them the list of other water-quality tests and the resource materials on water quality available in the classroom. For students with less science experience, pH testing is enough to introduce water-quality testing and the scientific method of writing lab reports.
Many students have a difficult time understanding the concept of pH measurement.
It is the most frequent mistake that even advanced science students make in writing reports for this lab. The lab will work just as well by forgoing other tests if they aren't available and using any available pH tests. Finish up this four-day activity with a day to work in the computer lab. This time is helpful to the students in formatting the data tables and writing their reports, or researching water quality further on the Internet. Time should be given as well to allow for a class discussion of results.