Progression toward Causal Mechanistic Reasoning through Phenomenon-Based Learning in Introductory Chemistry

The alignment of teaching and assessment in chemistry
courses is
critical for the practice of science and positive student learning
outcomes. This paper addresses how instructors can align what they
do in class with assessments across topics to improve students’
understanding and explanations of chemical phenomena. We drew on the
foundations of Phenomenon-Based Learning to introduce how observable
events can be used as an entry point into causal mechanistic reasoning,
an essential explanatory practice for scientists. This cross-institutional
study focuses on two chemical phenomena: dissolution and boiling point.
Students from three different learning environments completed phenomenon-based
tasks centered on these two phenomena, and their responses were analyzed
for different levels of causal mechanistic reasoning. We then analyzed
instructors’ dialogue for evidence of causal mechanistic reasoning
from content units where these phenomena were emphasized. Using students’
responses to the tasks and the instructor dialogue from the content
units, we observed students activating more resources related to particulate
behaviors when explaining the focal phenomena after instruction emphasized
using causal mechanistic reasoning to explain phenomena. This is noteworthy,
as it highlights the promise of sustained phenomenon-driven curricula
by helping students explain events using deeper levels of reasoning.
Our work provides evidence for instructional and curriculum developers
to design courses in a way where we are demonstrating to students
what practicing scientists do. We discuss implications for practitioners
that include ways to use observable events and chemical phenomena
as a foundation to promote causal mechanistic reasoning in chemistry.