An interactive homework to support student learning of measurement uncertainty in quantum mechanics

When thinking about measurement uncertainty in a laboratory experiment that features quantum mechanical effects, it is important to consider both the physical principles of underlying quantum theory (e.g. the uncertainty due to quantum mechanical superposition states) as well as the limitations of the measurement (e.g. the spread in outcomes due to instrumental imperfections). Prior research has found student difficulties with these sources of uncertainty both individually and in students' ability to distinguish between them. Additionally, students are less likely to access ideas related to experimental uncertainty in quantum mechanical contexts unless explicitly prompted. In this work, we have developed a simulation-homework activity focused on the Stern-Gerlach experiment to help students develop an understanding for the different ways that modifying the quantum state, improving the experimental setup, or collecting more data, will affect the resulting outcome distribution. The activity uses a purpose-built interactive simulation coupled with homework questions grounded in the literature on student thinking about uncertainty. The activity is effective in helping students distinguish between quantum mechanical uncertainty and uncertainty caused by instrumental imperfections, and in increasing the accessibility of instrumental limitations in this context.