Systematic experimental determinations of air-water interfacial areas were made for systems of wet but unsaturated glass beads. The areas decreased as water content increased and the pores filled up, but the decrease was not smooth. Inflections appeared in graphs of interfacial area vs percent water saturation. The shape of the plots and the position of the inflections depended upon the particle size distribution of the beads. It is believed that the inflections were caused by transitions from pendular to funicular configurations and by movement of water from larger to smaller pores, as the total water content in the system increased. To verify the reasonableness of these ideas, a simple two-dimensional model of a three-dimensional system was developed. It is shown that, in this model system, minimization of interfacial length (the two-dimensional equivalent of interfacial area) while maintaining constant interfacial curvature leads to transitions of the hypothesized type.