The Unknown Exercise: Engaging First-Year University Students in Classroom Discovery and Active Learning on an Iconic Chemistry Question

Scientific process thinking is usually lacking in first-year post-secondary general chemistry courses, as is a deep discussion of analytical techniques used to determine much of what we know about modern chemistry. A classroom activity is described here that brings the identification and characterization of a chemical unknown into the classroom, emphasizing self-directed, active, and teamwork learning within a social constructivist framework. In this way, the cognitive processes of identifying and characterizing an unknown can be emphasized separately from the psychomotor skills involved in the laboratory. Students work in pairs using self-directed learning to research the separation and characterization methods used by chemists. Each group advocates for a particular method, the class votes, and the instructor carries out the proposed method. The results are shown to the students (but not analyzed for them), and the cycle repeats until the unknown is identified. Students are assessed both individually and as a group. This activity was performed by 20-30 students in each of 3 years within two different first-year general chemistry contexts. Results show enhanced engagement in course and activity material and equivalent learning to lecture-delivered material based on assessment scores.