  Implementing a laboratory activity involves a complex interplay among
learning goals, available resources, feedback about the existing course, best
practices for teaching, and an overall philosophy about teaching labs. Building
on our previous work, which described a process of transforming an entire lab
course, we now turn our attention to how an individual lab activity on the
polarization of light was redesigned to include a renewed emphasis on one broad
learning goal: modeling. By using this common optics lab as a concrete case
study of a broadly applicable approach, we highlight many aspects of the
activity development and show how modeling was used to integrate sophisticated
conceptual and quantitative reasoning into the experimental process through the
various aspects of modeling: constructing models, making predictions,
interpreting data, comparing measurements with predictions, and refining
models. One significant outcome is a natural way to integrate an analysis and
discussion of systematic error into a lab activity.
