Inquiry project provides students multiple visualizations of molecular structures that differ only by just one key feature (a chemical bond) that makes the two structures behave very differently. This approach helps highlight key concepts around which students can integrate ideas.
The Rationale Behind the Feature (Specific Design Principle):
Eliciting comparisons between two entities can highlight relevant ideas. In this case the two objects are similar except for one specific feature which students must identify and connect to other relevant ideas through discussion and reflection.
Context of Use:
The inquiry project How Can We Recycle Old Tires? allows students to investigate the properties of pairs of materials with similar molecular structures. Tire rubber and plastic are both polymer structures, but tire rubber is cross linked with strong covalent bonds, while plastic polymers are held together by weak Van der Waals interactions. Students use the visualizations to investigate how the difference in bonding affects the properties of the two materials, such as the melting point or elasticity. A similar activity structure guides students in comparing two crystalline structures (metals and ceramics).
Analysis of students reflection prompts showed that students were able to build on their ideas from the tire activity to the plastic activity, suggesting that the comparisons were effective. The comparison between metals and ceramics was less effective, possibly because of the greater differences between the two visualizations and that the differences between the chemical bonds were not explicitly represented in the visualizations.
Linn, M. C. (2005). WISE Design for Lifelong Learning—Pivotal Cases. In P. Gärdenfors & P. Johannsson (Eds.), Cognition, Education and Communication Technology. Mahwah, NJ: Lawrence Erlbaum Associates.
McElhaney, K.W. (2007). Using Pivotal Cases to Help Learners Understand and Integrate Chemistry Representations. Paper presented at the annual meeting of American Educational Research Association, Chicago, IL, April 9-13.