Which process describes water moving through small pores due to attraction to surfaces and between molecules?

Which process describes water moving through small pores due to attraction to surfaces and between molecules?

• A. Capillary action
• B. Diffusion
• C. Osmosis
• D. Adsorption

Answer: (A)

Capillary action describes water moving through tiny pores because it is attracted to the surfaces of the pores and to other water molecules. In narrow spaces, adhesion to the pore walls pulls the water upward, while cohesion between water molecules helps pull adjacent water along. This combination allows water to wick through porous materials like soil, paper, or plant vessels, often even against gravity in very small channels. Diffusion is about spreading from higher to lower concentration and isn’t driven by surface attraction in pores. Osmosis involves water crossing a semipermeable membrane toward higher solute concentration. Adsorption is the sticking of molecules to a surface, not their movement through a network of pores.

Capillary action describes water moving through tiny pores because it is attracted to the surfaces of the pores and to other water molecules. In narrow spaces, adhesion to the pore walls pulls the water upward, while cohesion between water molecules helps pull adjacent water along. This combination allows water to wick through porous materials like soil, paper, or plant vessels, often even against gravity in very small channels. Diffusion is about spreading from higher to lower concentration and isn’t driven by surface attraction in pores. Osmosis involves water crossing a semipermeable membrane toward higher solute concentration. Adsorption is the sticking of molecules to a surface, not their movement through a network of pores.