The Parallelometer: a mechanical device to study curvature

A simple mechanical device is introduced, the parallelometer, that can be used to measure curvatures of surfaces. The device can be used as a practical illustration of parallel transport of a vector and to study Berry phase shift when it is carried along a loop on the surface. Its connection to the Foucault pendulum is discussed. The experimental results can be successfully compared with the theoretical expectations. The experiment is inexpensive and conceptually easy to perform and understand for a beginner.