The ability to use representations of molecular structure to
predict the macroscopic properties of a substance is central to the development
of a robust understanding of chemistry. Intermolecular forces (IMFs) play an
important role in this process because they provide a mechanism for how and
why molecules interact. In this study, we investigate student thinking about IMFs (that is, hydrogen bonding, dipole−dipole interactions, and London dispersion forces) by asking general chemistry college students to both describe their understanding in writing and to draw representations of IMFs. Analysis of
student drawings shows that most students in our study did not have a stable coherent understanding of IMFs as interactions between molecules. At least
55% of the students in our study unambiguously represented each IMF an
interaction or bond within a single molecule, while only 10−30% of students
represented each IMF as an interaction between molecules Furthermore, the
majority of students (59%) were not consistent in the way that they
represented the different IMFs (as within or between). That is, their representations varied depending on the IMF. Student written
descriptions of intermolecular forces were typically quite ambiguous, meaning that it was not possible to determine from the student
description alone whether the student understood IMFs as bonds or interactions. It was only when the student’s representation was
consulted that we could determine whether a particular student had an appropriate understanding of IMFs. We believe that in
situations where spatial information is crucial, free-form drawn representations are more likely to provide meaningful insight into
student thinking