Scientific Argumentation

When scientists construct explanations of how the universe behaves, they engage in scientific argumentation from evidence. That evidence may be mathematical or it may be based on data collected in an experiment. Students need to grow to be scientifically literate. They need to be able to evaluate arguments that they read in newspapers and in magazines. They need to be able to evaluate claims that they hear on television or from their friends and family.

The College Board defines seven science practices for all AP science students. Science Practice 6 states that "The student can work with scientific explanations and theories." This is further broken down into four sub-skills.

6.1 The student can justify claims with evidence.

6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices.

6.3 The student can articulate the reasons that scientific explanations and theories are refined or replaced.

6.4 The student can make claims and predictions about natural phenomena based on scientific theories and models.

The scientific argumentation process can be modeled in many ways, but my favorite is that espoused by Katherine McNeill and Joseph Krajcik. It can be found in the book Science as Inquiry in the Secondary Setting (Luft,Bell, Gess-Newsome, eds.)¹. In chapter 11, they outline the framework for scientific explanation. This framework includes three components: a claim, evidence to support the claim, and reasoning that connects the evidence to the claim.

Claim: A statement that makes an assertion or a conclusion that answers the original question; a statement of whether the data support the hypothesis or does not support the hypothesis.

Evidence: In a lab, the evidence is the data collected and any graphs or charts produced using this data; in an explanation, it could also include multiple representations such as motion graphs, force diagrams, circuit diagrams, bar charts, sketches, etc. The evidence needs to be sufficient, appropriate and accurate.

Reasoning: These are statements that link the evidence to the claim and state how the evidence supports the claim.

This framework (CER) can be used in any context where a student is asked to "justify your claim" or "support your answer with physics principles". It can also be used for the conclusion of a lab report.

McNeill and Krajcik have five different strategies¹ they outline for how teachers can support students in engaging in scientific argumentation.

1. Teachers can provide students with reasons for constructing scientific explanations.

2. Teachers can connect scientific argumentation to everyday explanations.

3. Teachers should make the framework explicit.

4. Teachers should model the process of argumentation and critique the student's explanation.

5. Teachers should provide feedback for the students as they write explanations.

Trevor Register has wonderful blog post about his experiences implementing this framework in his classroom. He includes some wonderful links at the end of the post, including links to other blogs and the McNeill/Krajcik article.

Here is a rubric I adapted from the McNeill/Krajcik article.

¹McNeill, K. L. & Krajcik, J. (2008). Inquiry and scientific explanations: Helping students useevidence and reasoning. In Luft, J., Bell, R. & Gess-Newsome, J. (Eds.). Science as inquiry in the secondary setting. (p. 121-134). Arlington, VA: National Science Teachers Association Press.