The physical nature of the forces acting between a laterally vibrating probe in air near a solid surface has been investigated using a calibrated method for the experimental determination of dynamic force. The frequency response of the probe vibrating near its fundamental bending resonance was measured as a function of distance as the probe approached the surface. The experimental results were compared with a continuum‐mechanical model of bending waves in a rod; the nature of the forces was inferred by determining the effect of various boundary conditions on the standing‐wave motion of the probe. The results conclusively show that while in the initial stage of approach the force is dominated by fluid‐dynamic effects, in the final stage of approach an elastic force appears. The appearance of the elastic deformation is characterized by a shift in the resonant frequency of the vibrating probe. ©1996 American Institute of Physics.