Notley, ShannonBiggs, SimonCraig, Vincent S. J.2015-10-082015-10-080034-6748http://hdl.handle.net/1885/15811A method is described to determine the spring constant of colloid probe cantilevers used in force measurements with the atomic force microscope. An oscillatory drive applied to the substrate is coupled by viscous interactions to the colloid probe. The dynamic response of the probe, which is unaffected by static interactions, is then used to determine the spring constant of the cantilever. Thus an accurate calibration of the spring constant may be performed simultaneously with a normal colloidal probe force measurementin situ.S.N. and S.B. acknowledge the support of the Center for Multiphase Processes, a Special Research Center of the Australian Research Council. V.C. acknowledges support from the Australian Research Council for the provision of a Postdoctoral Fellowship.http://www.sherpa.ac.uk/romeo/issn/0034-6748..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 8/10/15). Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments and may be found at https://doi.org/10.1063/1.1597950Keywords: Atomic force microscopy; Drag; Dynamic response; Force measurement; Hydrodynamics; Probes; Viscosity; Colloid probe cantilevers; Colloids2003-0910.1063/1.15979502015-12-12