What term describes the ratio between the weight of water and the weight of solid particles?

The correct term that describes the ratio between the weight of water and the weight of solid particles is moisture content. Moisture content is a critical factor in geotechnical engineering as it influences various properties of soil, such as strength, compressibility, and permeability. It is typically expressed as a percentage, indicating how much water is present in a soil sample relative to the solid particles within that sample.

Understanding moisture content is vital for applications such as determining the suitable conditions for soil compaction and predicting the behavior of soil under varying moisture conditions. The other terms listed relate to different aspects of soil and fluid dynamics. Soil density pertains to the mass per unit volume of soil, which does not specifically address the relationship between water weight and solid particles. Permeability refers to the ability of the soil to transmit water, and shear strength denotes the resistance of soil to sliding or shearing forces, neither of which directly describes the moisture to solid particle weight ratio.