Investigating the Connection Between Scale and Intermolecular Forces in the General Chemistry Laboratory

The American Association for the Advancement of Science (AAAS) has outlined four themes that define science literacy; these are systems, models, constancy and change, and scale. More recently, the National Research Council has released the framework for K-12 science education that includes “Scale, Proportion, and Quantity”. Our research has already shown that scale literacy is a better predictor for success in a general chemistry course than traditional measures and integrating scale as a theme in the undergraduate general chemistry curriculum has been accomplished through a variety of methods. Of particular interest was developing a laboratory sequence that would help students increase their knowledge of chemistry concepts through explicit inclusion of scale concepts.One particular activity was developed based on the difficulty students have in understanding the important role of intermolecular forces in chemistry. Given that intermolecular forces exist on the particle level (far below the threshold of sight) it is not surprising that students have difficulty when asked to describe how these forces can be used to explain the observed macroscopic properties of substances. This activity gave students the opportunity to think about and explore the molecular level on which these forces exist through model building and experimentation. The preliminary data collected from this activity will show how incorporating scale concepts into this activity helped students to not only better understand intermolecular forces but also how to use this understanding to develop explanations for observed trends in the properties of chemical substances