Which statement best describes permeability?

• A. Permeability is the ability to transmit fluids.
• B. Porosity is the ability to transmit fluids.
• C. Porosity is the amount of heat, Permeability is color.
• D. Permeability is the amount of dissolved minerals.

Answer: (A)

Permeability is the ability of a material to transmit fluids. This means how easily water, oil, or air can move through the pore spaces in soil or rock. What matters is how connected those pores are and how wide the pathways are. If the pore spaces form continuous channels, fluids flow readily; if they’re isolated or very narrow, flow is slow.

Porosity, on the other hand, is about how much void space there is—how much fluid a material could hold, not how fast it can move through. A material can have a lot of empty space but still restrict flow if the pores aren’t well connected. For example, clay can have notable porosity but low permeability because its tiny, poorly connected pores don’t allow fluids to pass quickly. The other options describe heat, color, or mineral content, which are not definitions of permeability.