A computer-controlled classroom model of an atomic force microscope

The concept of "seeing by feeling" as a way to circumvent limitations on sight is universal on the macroscopic scale-reading Braille, feeling one's way around a dark room, etc. The development of the atomic force microscope (AFM) in 1986 extended this concept to imaging in the nanoscale. While there are classroom demonstrations that use a tactile probe to map the topography or some other property of a sample, the rastering of the probe over the sample is manually controlled, which is both tedious and potentially inaccurate. Other groups have used simulation or tele-operation of an AFM probe. In this paper we describe a teaching AFM with complete computer control to map out topographic and magnetic properties of a "crystal" consisting of two-dimensional arrays of spherical marble "atoms." Our AFM is well suited for lessons on the "Big Ideas of Nanoscale" such as tools and instrumentation, as well as a pre-teaching activity for groups with remote access AFM or mobile AFM. The principle of operation of our classroom AFM is the same as that of a real AFM, excepting the nature of the force between sample and probe.