Mental models for scientific learning are important cognitive tools that students use to not only take in new information, but to help problem solve in new contexts. If conceptual parts are inaccurate, then the resulting models will not be useful. Students in college general chemistry courses are presented with multiple abstract topics and often struggle to fit these parts into complete models. This is especially true for the topics relating to the quantum mechanical nature of atoms and bonding. For conceptual change to occur, we as instructors must recognize the students' incorrect and incomplete models and help them to accommodate the accepted model. From prior studies, it is clear that novice students retain substantial inaccuracies and misconceptions about the nature of atoms, even after completing general chemistry. Some of the most resilient misconceptions of atomic structure involve electron particles moving on a set path -- like planets in an orbit or in orbiting shells. Most of these misconceptions arise from classical analogies and misleading metaphors used in instruction and textbooks, including teaching the Bohr model first and moremost. In this paper, we present an alternative approach to teaching introductory students about light-matter interactions at th atomic level. Additionally, we will present a series of guided interactive activities developed to help students explore how light interacts with matter and begin to develop physical intuition based on this approach. While students come to college-level general chemistry having been told that light consists of photon and that these that are absorbed and emitted by atoms and molecules, these facts are not anchored by a correct understanding of what light is or a correct physical picture of just how it interacts with matter. To remedy this, we have developed an approach to light-matter interaction in which student learn (1) that light of a particular frequency is an electric field alternating in magnitude and sign at tha frequency, (2) that the electron clouds of atoms (and molecules) have natural frequencies at which they can oscillate, (3) that the electric field of light tugs on the charge cloud of atom, and (3) light and matter interact when the frequency of the alternating pushes and pulls of the electric filed of the light matches one of the natural frequencies of the atom electron cloud. That is, light and matter interact when their frequencies come into resonance.

Replacing the Bohr atomic model with an accessible picture of how atoms and light truly interact

2019 Spring National Meeting

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