Models in the Classroom–Help or Hindrance? A Look at the Variables That Influence Students’ Success on Representational Translation Tasks in the Chemistry Classroom

• In Event: Spatial Thinking in Chemistry

Abstract

Chemists must rely on visuo-spatial thinking to imagine and reason with molecules. Many representations have been developed to aid in spatial thinking (Goodwin, 2008). Though experts are able to easily translate between representations, novices have difficulty mastering this technique (Bodner & Domin, 2000). Instructors will often use 3D models to help students visualize the translation between 2D diagrams (e.g., Ealy 2004). Though research has been done on the use of 3D models (e.g. Ferk et al., 2003), we have found no reports on the methods students use to translate 3D models to 2D diagrams in the classroom setting. Here, we examine the spatial demands, common conventions, and challenges associated with 3D model use in the Organic Chemistry classroom and their effects on student success at representational translation tasks.

Organic Chemistry students were tested on their ability to translate 3D models into 2D Newman diagrams in the classroom setting. Participants were seated at the front of a large lecture hall and divided equally among three seat sections (left, center, right). Molecules were presented to students via two presentation methods (lecture models, document camera projections) and in three orientations (end-on, wide-view, upright). Diagrams were coded under the hypothesis that students will use a step-wise approach to translate from a 3D model to a 2D diagram. Through this approach, students will create a framework from which a Newman diagram is created. At each step, visuo-spatial decisions are made regarding the translation process (e.g., choice of perspective from which to create the Newman diagram and the decision to mentally rotate during translation). Each step of this approach and the overall accuracy of participants’ diagrams were coded.

We have found that our participants use preferred directional approaches and spatial decisions when drawing Newman diagrams, thus creating a “common framework”. For example, if shown a wide-view molecule via the document camera, students will translate the left carbon center of the model to the front of the Newman diagram significantly more often than the right carbon center. The spatial demands as well as classroom and textbook conventions are addressed in relation to these participant preferences, and we discuss the use of this common framework in the instruction of this diagram.

The effects of seat location, presentation method, and molecule orientation on participants’ use of this common framework and their accuracy on task were also examined. Significant interactions between presentation methods and seat locations were found, as well as interactions between all three factors. Participants at the right side of the classroom had significantly lower performance than the other seat locations when wide-view molecules were shown with lecture models. Such differences were lessened with use of the document camera. We discuss the challenges of using 3D models in the classroom, and the impact of the above effects on student performance and accuracy. The application of these findings is considered in regard to model use in this and other STEM disciplines.

Authors

• Bryna Kumi, University of Maryland - College Park

• Bonnie L. Dixon, University of Maryland - College Park