porosity

References

porosity

in solids

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Last updated

July 23, 2026

Quick Summary

Porosity is the ratio of empty space (void volume) to the total bulk volume of a solid material. This empty space can be in the form of pores between grains or crystals, or cracks within the material.12

In rocks, porosity is influenced by factors such as the compaction of sediment, the arrangement and shape of grains, and the presence of cementing minerals. For example, well-sorted sediments, which have grains of similar sizes, can have significant porosity, while poorly sorted sediments have decreased porosity.2

Porosity is also a key property in materials like coal, affecting the rate of chemical reactions due to the increased internal surface area it provides. The accessibility of this internal surface area depends on the size and shape of the pores.3

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metallurgy
Porosity
A major problem in castings, porosity is principally caused by the shrinkage that accompanies solidification. Molds are designed to feed metal to the casting in order to keep it full as solidification proceeds, but, if this feeding is incomplete, the shrinkage will show up…
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A major problem in castings, porosity is principally caused by the shrinkage that accompanies solidification. Molds are designed to feed metal to the casting in order to keep it full as solidification proceeds, but, if this feeding is incomplete, the shrinkage will show up…
Read More

coal utilization
Porosity
Porosity is the fraction of the volume of an apparent solid that is actually empty space. Owing to porosity, the surface area inside a coal particle is far higher than the external surface area. In any gas-solid or liquid-solid reaction, the rate of reaction…
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Porosity is the fraction of the volume of an apparent solid that is actually empty space. Owing to porosity, the surface area inside a coal particle is far higher than the external surface area. In any gas-solid or liquid-solid reaction, the rate of reaction…
Read More

sedimentary rock
Clast-supported conglomerates
…is attributable to their high porosity and permeability. Porosity is the volume percentage of “void” (actually fluid- or air-filled) space in a rock, whereas permeability is defined as the rate of flow of water at a given pressure gradient through a unit volume. The interconnectedness of voids in conglomerates contributes…
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…is attributable to their high porosity and permeability. Porosity is the volume percentage of “void” (actually fluid- or air-filled) space in a rock, whereas permeability is defined as the rate of flow of water at a given pressure gradient through a unit volume. The interconnectedness of voids in conglomerates contributes…
Read More

dye
Fibre porosity
Fibres are made by various spinning techniques that produce bundles of up to several hundred roughly aligned strands of polymer chains with length-to-diameter ratios in the thousands. For the dyeing process, an important characteristic of fibres is their porosity. There is a huge number…
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Fibres are made by various spinning techniques that produce bundles of up to several hundred roughly aligned strands of polymer chains with length-to-diameter ratios in the thousands. For the dyeing process, an important characteristic of fibres is their porosity. There is a huge number…
Read More

rock
Porosity
The term rock refers to the bulk volume of the material, including the grains or crystals as well as the contained void space. The volumetric portion of bulk rock that is not occupied by grains, crystals, or natural cementing material is termed porosity. That…
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The term rock refers to the bulk volume of the material, including the grains or crystals as well as the contained void space. The volumetric portion of bulk rock that is not occupied by grains, crystals, or natural cementing material is termed porosity. That…
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petroleum
Accumulation in reservoir beds
The porosity (volume of pore spaces) and permeability (capacity for transmitting fluids) of carrier and reservoir beds are important factors in the migration and accumulation of oil. Most conventional petroleum accumulations have been found in clastic reservoirs (sandstones and siltstones). Next in number are the carbonate…
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The porosity (volume of pore spaces) and permeability (capacity for transmitting fluids) of carrier and reservoir beds are important factors in the migration and accumulation of oil. Most conventional petroleum accumulations have been found in clastic reservoirs (sandstones and siltstones). Next in number are the carbonate…
Read More

soil
Grain size and porosity
The grain size of soil particles and the aggregate structures they form affect the ability of a soil to transport and retain water, air, and nutrients. Grain size is classified as clay if the particle diameter is less than 0.002 mm (0.0008 inch), as…
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The grain size of soil particles and the aggregate structures they form affect the ability of a soil to transport and retain water, air, and nutrients. Grain size is classified as clay if the particle diameter is less than 0.002 mm (0.0008 inch), as…
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