Which statement describes capillary action in relation to moisture in compacted material?

Which statement describes capillary action in relation to moisture in compacted material?

• A. Moisture is drawn up to the surface
• B. Moisture drains downward
• C. Moisture remains evenly distributed
• D. Moisture evaporates immediately at the surface

Answer: (A)

Capillary action describes how liquids move through tiny pores because adhesive and cohesive forces pull the moisture upward in the pore network. In compacted material, these forces can draw water from lower, wetter zones toward the surface, causing moisture to rise even when gravity would pull it downward. This upward transport is why moisture is drawn up to the surface. Draining downward is driven by gravity, not capillary forces; staying evenly distributed would require no net movement, which capillary action does not produce; and evaporation at the surface is about evaporation, not the vertical movement of liquid within the soil.

Capillary action describes how liquids move through tiny pores because adhesive and cohesive forces pull the moisture upward in the pore network. In compacted material, these forces can draw water from lower, wetter zones toward the surface, causing moisture to rise even when gravity would pull it downward. This upward transport is why moisture is drawn up to the surface. Draining downward is driven by gravity, not capillary forces; staying evenly distributed would require no net movement, which capillary action does not produce; and evaporation at the surface is about evaporation, not the vertical movement of liquid within the soil.