It is often said that writing is a window into a person’s thinking. As teachers, we must know what our students are thinking in regards to the concepts we teach. The whole point of the pedagogical approach promoted by the NGSS movement is to help the larger science education community get students thinking more, and more deeply about science content.
I think we should be asking our students to make written or verbal statements in our classes very often. In science class, this type of communication is typically in the form of a claim about what a result means or an explanation about how something works the way it does. In either case, the claim or explanation needs to be supported by thinking that is grounded in facts and logic.
The CER Scaffold: Helpful and Hindering at the Same Time
The Claim, Evidence, Reasoning (CER) scaffold has been widely adopted by science teachers. While I think the CER scaffold has provided some much needed help to support writing in science, my students and I have also found it to be confounding. This is because it separates evidence and reasoning from each other when in reality evidence is a critical part of reasoning (for more comments on this, see my previous post What is Reasoning?). Evidence is not something that should be considered separate from reasoning since reasoning is really a combination of evidence and additional commentary that attempt to convince others why a claim or explanation is plausible. I prefer to call reasoning an argument. Others call it justification (see Arguing Density by Stephanie O’Brien).
Some writing prompts we give our students are more suited toward claims: “What is the optimal mixture ratio of H2 and O2 to propel a rocket?” Other writing prompts we give are more suited toward explanations: “Why does Kona typically get onshore winds in the late morning and afternoon?” I think an argumentative writing piece consists of two parts, not three parts as suggested by the CER scaffold: 1 - the statement (which is a claim or explanation) and 2 - the argument. Instead of claim, evidence, and reasoning think statement and argument.
Science Reasoning Rubric
Building upon these thoughts and my revised Components of Scientific Reasoning figure from What is Reasoning? (see Figure 1), I put together a Science Reasoning Rubric that can be used for many writing prompts in a Chemistry class. It can be used whether a prompt is more suited toward a claim or an explanation (see Figure 2). Together, I think these documents help support students better through the argumentative writing process than CER does. I like that the rubric can be used for lots of the writing tasks students will encounter in a Chemistry class. This means students get used to seeing it, and this consistency is helpful as students write explanations and claims throughout the year.
What Counts as Evidence?
One question that may come up a lot is, “What counts as evidence?” As shown in Figure 1, evidence can be multi-faceted ranging from core ideas to models to observations or raw data. Before students start a writing prompt, it may sometimes be helpful to guide them toward what could be considered evidence for the task by pointing them toward relevant core ideas, cross-cutting concepts, models, data, etc. This is up to teacher discretion and the art (i.e. challenging part) is to provide this guidance without giving too much away to the students. I shared my own working list of core ideas in a previous Chemed X blog post, Toward an Accessible Set of Chemistry Core Ideas to Help Students Make Sense of Phenomena.
Another thing I want to note here is that the statement doesn’t necessarily need to come first and then the argument second in a written piece. As shown in Figure 1, the statement and argument should be developed together and in an argumentative piece of writing, it is perfectly acceptable to jump back and forth between comments that establish a claim or explanation and commentary providing reasons it should be believed.
