The integration of chemical phenomena into chemistry classes has been a topic of interest for reform efforts, particularly at the K-12 level. The next phase of this work builds on elements from K-12 science standards (three-dimensional learning) and involves the chemical phenomenon of dissolution (lithium chloride dissolving in water and heat generation as a result). It was hypothesized that certain elements of learning environments have the potential to impact student learning outcomes. Therefore, this project characterized several elements of chemistry classes to see how dissolution was taught and how students were responding to a dissolution based task as a potential result of their classroom instruction. Dialogue was recorded for instructors from three different chemistry learning environments during the time in which they were covering solutions chemistry. Students completed a three-part task related to the dissolution of lithium chloride. Within the learning environments, we quantified how much active learning and three-dimensional learning was modeled to students to see if there was a relationship between the amount of time spent in these approaches to learning and student outcomes on the task. Results suggested that just because active learning was integrated into a course did not mean students were provided opportunities to engage in the intellectual work of scientists (i.e., reasoning about how and why chemical phenomena occur). It was found that students had higher levels of reasoning about dissolution when more three-dimensional learning was modeled within their chemistry classes. This led us to question the specific ways in which instructors were modeling explanations about phenomena to students to see if more sophisticated levels of reasoning (causal mechanistic reasoning) in class led to higher levels of reasoning in students’ understanding of more phenomena.

The final chapter of this dissertation takes elements from previous chapters and looks at them through two new frameworks: phenomenon-based learning (learning through the use of an observable event) and causal mechanistic reasoning (a type of scientific reasoning that emphasizes underlying entities and behaviors). Moving beyond general three-dimensional learning and zeroing in on specific parts of explanations and how explanations are modeled is important for the alignment of assessments and instruction. First, students were tasked with answering two phenomenon-based questions regarding the dissolution of lithium chloride and the boiling points of ethanol and diethyl ether. Their responses were characterized for evidence of causal mechanistic reasoning, a critical practice for chemists that involves identifying and unpacking the behaviors of entities below the level of a given phenomenon. Next, the amount of time instructors spent modeling causal mechanistic reasoning to students during units on dissolution and intermolecular forces (most closely related to the phenomena of interest) was quantified. Results suggest that the more causal mechanistic reasoning modeled in class, the more causal mechanistic reasoning will be reflected in student learning outcomes. This study also involved the characterization of causal mechanistic reasoning on semester exams and it was found that there are very limited opportunities to reason about chemical phenomena on exams. All of these factors together could have the potential to impact students’ ability to reason causal mechanistically about phenomena. Implications from this work include how to incorporate phenomena more readily into chemistry instruction and how to format assessment questions to align with causal mechanistic reasoning, overall leading to curriculum and instructional changes in our introductory chemistry classrooms.

This work begins with a focus on chemistry exams, a critical part of a learning environment, as exams and assessments often signal to students what matters in a course. Semester exams were collected from three different chemistry learning environments (coined the active, didactic, and core ideas learning environments), each differing in their approach to active learning and curriculum. Because calls to reform have emphasized engaging students in the practices of scientists, exam questions were characterized for their potential to engage students in three-dimensional learning, causal mechanistic reasoning, and math. It was found that a typical semester exam contains mostly recall of facts or mathematical skills and there were very few opportunities for reasoning about chemical phenomena through underlying chemical principles and ideas. This finding could lead to inequitable assessment practices, as over-emphasizing mathematical skills can have a negative impact on students who were not given proper mathematical preparation prior to college. With this in mind, it was found that if questions shifted away from mathematical skills and toward reasoning about phenomena, student pass rates would increase, creating a more equitable environment overall. Implications involve ways in which we can restructure assessment questions to reflect reasoning, as opposed to recall of facts.

There is no denying science is not only central to our world but becoming increasingly complex as we advance in technology and innovation. As a result, approaches to science education are changing in tandem with discoveries about how people learn and where individuals use their knowledge from science classes. Chemistry is a foundational gateway course into almost all STEM disciplines, and therefore a great deal of research has focused on the ways in which we can improve the teaching and learning of chemistry. Over the past several decades, there have been multiple approaches to improvement efforts. One approach has been to look towards chemistry learning environments to see what aspects of these environments are impacting student learning outcomes. And as a result, chemistry education (and in general, science education) reform efforts have called for the integration for more opportunities for students to learn about how and why phenomena happen in the real world, as opposed to rote facts and skills, as the former better reflects the work of practicing scientists. Therefore, this dissertation focuses on characterizing the elements of three different chemistry learning environments through the lens of exploring chemical processes and phenomena.