REPRINT – Nimmo,, 2004, Porosity and Pore Size Distribution, in Hillel, D., ed. Encyclopedia of Soils in the Environment: London, Elsevier, v. 3, p. 295303. (monodisperse) packs to about the same porosity as spheres. In a polydisperse sand, the fitting of small grains within the pores between large ones can reduce φ, conceivably below