Perform side-by-side, quantitative comparisons of water movement through soils. Four different soil samples show the relationships between particle size, shape, and uniformity with porosity and permeability. The expansive teacher's guide includes background information on aquifers and groundwater flow, as well as activities that cover porosity, permeability, specific yield, capillary action, and settling rates. Procedures for the testing of native soils are also included. Column size, 16" L × 1 1/2" diam; apparatus size, 21" H × 6 1/2" W × 7" D.