We have designed and fabricated an ex situ optical cantilever beam magnetometer to measure the magnetization and the magnetostriction of ferromagnetic materials. We discuss the working principle of a cantilever beam magnetometer and derive the theory of the cantilever bending due to magnetic torque acting on the sample attached to the cantilever substrate. We also present the results for bulk iron obtained using the cantilever beam magnetometer.

We discuss an advanced undergraduate project on spin noise spectroscopy of atomic rubidium vapor. The spin noise is digitized using a consumer sound card and analyzed by a fast Fourier transform. Students gain competence in digital data acquisition and processing, and the idea of analyzing a noise signal is emphasized.

We explore the difficulties that advanced undergraduate and graduate students have with non-relativistic quantum mechanics of a single particle in one spatial dimension. To investigate these difficulties we developed a conceptual survey and administered it to more than 200 students at 10 institutions. The issues targeted in the survey include the set of possible wavefunctions, bound and scattering states, quantum measurement, expectation values, the role of the Hamiltonian, and the time-dependence of the wavefunction and expectation values. We find that undergraduate and graduate students have many common difficulties with these concepts and that research-based tutorials and peer-instruction tools can significantly reduce these difficulties. The findings also suggest that graduate quantum mechanics courses may not be effective at helping students to develop a better conceptual understanding of these topics, partly because such courses mainly focus on quantitative assessments.