  Quantum mechanics can seem like a departure from everyday experience of the
physical world, but constructivist theories assert that learners build new
ideas from their existing ones. To explore how students can navigate this
tension, we examine video of a focus group completing a tutorial about the
"particle in a box." In reasoning about the properties of a quantum particle,
the students bring in elements of a classical particle ontology, evidenced by
students' language and gestures. This reasoning, however, is modulated by
metacognitive moments when the group explicitly considers whether classical
intuitions apply to the quantum system. The students find some cases where they
can usefully apply classical ideas to quantum physics, and others where they
explicitly contrast classical and quantum mechanics. Negotiating this boundary
with metacognitive awareness is part of the process of building quantum
intuitions. Our data suggest that (some) students bring productive intellectual
resources to this negotiation.

Physics Education;Quantum Physics