porøs

Porøs is a term used in Danish and Norwegian to describe a material that contains voids or pores. Such materials have spaces that can be occupied by air, liquids, or gases, and the pore network can influence properties like weight, strength, and transport.

Porosity refers to the fraction of a material’s volume that is void space. Porosity can be open (interconnected pores that allow fluids to flow through the material) or closed (pores that are isolated and do not contribute to flow). The total porosity is the sum of open and closed porosity, while pore connectivity and pore-size distribution determine how easily fluids move through the material.

Porosity is related but not identical to permeability. Porosity measures how much space is void, whereas permeability measures the ability of a fluid to move through that space. A material can have high porosity but low permeability if its pores are poorly connected or very small. Conversely, a highly connected pore network can yield high permeability even if porosity is moderate.

Characterization and measurement of porosity employ several methods. Archimedes principle can give bulk porosity from density measurements, while mercury intrusion porosimetry and gas adsorption (such as BET) characterize pore-size distributions at different scales. Imaging techniques like micro-computed tomography provide three-dimensional views of pore structure.

Porous materials appear in many forms, including ceramics, foams, concrete, carbon aerogels, and wood, as well as natural rocks and soils. They play crucial roles in filtration, insulation, catalysis, battery electrodes, and hydrocarbon reservoirs, where pore size, connectivity, and stability determine performance. The term porøs also reflects this broad relevance across science and engineering.