Analyzing Land Use in a Watershed Using the CERR Model

Christopher Kopco
STEM & Environmental Literacy Coordinator
Claud E. Kitchens Outdoor School at Fairview
Washington County Public Schools, Maryland

Students will leave Claud E. Kitchens Outdoor School at Fairview (Fairview Outdoor School) with a love for science and the great outdoors and will see themselves as capable environmental scientists who can make a difference in their own communities. That’s the claim that we support every day through the use of the Claim, Evidence, Reasoning, Rebuttal (CERR) model that we use with students who visit our facility. In this model, students make a scientific claim about an observed scientific issue or phenomena, and support that claim through the evidence (data) they have gathered, interpreting that data to provide their reasoning. Often the data can be used to support alternate claims, so in this model students are also tasked with identifying an alternate claim, and explain why that alternate claim is not appropriate. For our purposes at Fairview Outdoor School, we shorten the process to Claim, Evidence, Reasoning due to time constraints.

Situated on over 100 acres of forest, field, and stream, Fairview Outdoor School is the perfect place to reinforce the CERR model used in science classrooms throughout Washington County Public Schools. Here, students are provided with the resources and tools they need to carry out outdoor investigations to help them to answer important scientific questions about their environment and to help them to formulate solutions to problems they identify.

One example of this process can be found in our Go With the Flow lesson that focuses on our local watershed and how the use of the surrounding land impacts our local stream and how that eventually impacts the Chesapeake Bay. Students climb our firetower to get a firsthand look at the local watershed, then use models to demonstrate how land use affects our local stream, Tom’s Run. From there, students visit Tom’s Run where they are posed the following question, “How responsibly are our neighbors upstream using their land?” It is at this point that students get to work gathering and classifying macroinvertebrates according to their pollution tolerance, and, more recently, testing the quality of the water in Tom’s Run using the new GaiaXus water probes provided generously through a partnership with GaiaXus. Students gather data in their science notebooks throughout this process. The Fairview teaching staff guides students through discussions using talk moves (strategies for extending student thinking and engaging all students in productive educational discussions), and questioning techniques to help them to analyze this data to determine what it all means. At this point students have all the tools they need to begin the CERR process.

First, referring back to the question given to them at the beginning of the investigation, students make a Claim in their science notebooks about how responsibly our neighbors upstream are using their land. Depending on the experience level of the students visiting that day, they may be provided with a sentence starter such as “Our neighbors are treating the land . . .”  Next students refer to the data they have collected to provide Evidence to support their Claim. Once again, depending on the experience level of the students, this may be done individually or in partners if students need a little more support. Finally, students analyze that data to give the Reasoning for their Claim, explaining how the data supports their claim. If they found that the majority of the macroinvertebrates they collected were not tolerant of pollution, what does that tell them about how the land further upstream in our watershed is being used? What if the majority of the macroinvertebrates are pollution tolerant? Students then share their ideas with others, to check for understanding.

So how does this help our students to gain confidence in their abilities as environmental scientists? Using science notebooks, hands on data collection, and the CERR process students gain more confidence in their ability to think like an environmental scientist because this process allows them to collect the evidence and to develop an understanding of that evidence to back up the claims that they make. But what about other scientific disciplines outside of environmental science? Can this process make an impact there as well?  I encourage you to try it and see. You won’t be disappointed!