What natural force causes water to move through pores in soil and rocks?

The natural force that primarily causes water to move through pores in soil and rocks is gravity. When water is present in the soil, gravity pulls it downward, causing it to percolate through the soil and rock layers. This gravitational force is essential in shaping groundwater flow and determining how much water can infiltrate the ground, as well as how quickly it moves through different materials.

While other processes, like capillary action, can influence water movement in small amounts, especially in finer soils, gravity remains the dominant force in the overall movement of water through larger volumes and deeper layers of soil and rock. Hydrostatic pressure relates to the pressure exerted by a fluid at equilibrium due to the force of gravity, while osmosis refers to the movement of water across a semi-permeable membrane, specifically driven by concentration gradients, rather than soil and rock movement.