2007-12-11 01:21:08 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
Porosity is the percentage of 'air' space in a solid object.
Permeability is the ability of a solid object to pass gas or liquids through itself.
An object may be porous, but if all the interstitial spaces are closed off from each other there will be little permeability. If there are connections between all the little spaces, then gas and liquid can flow through.
Styrofoam is an example of something that is very very porous (lots of little air pockets), yet because all the air pockets are separate and closed off from each other, it is hard to pass liquid or gas through a styrofoam wall so it is not very permeable.
Sandstone is also very porous (sometimes upwards of 30% space to 70% solid rock), but the spaces are usually connected, so liquids and gasses can pass through a wall of sandstone.
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2007-12-11 01:48:49 · answer #1 · answered by tlbs101 7 · 3⤊ 0⤋
Porous implies the presence of significant pores such as bricks that may consist of sintered (fused) particles and can pass water. Permeable implies that the 'pores' are so small that they may discriminate between molecules of different sizes. A permeable membrane may allow some chemicals through but exclude others.
2007-12-11 01:41:27 · answer #2 · answered by Kes 7 · 0⤊ 0⤋
Porous means there are actual holes. Permeable means that passage occurs but not necessarily through holes.
Example: If a buried PVC pipe carrying water is in soil that is contaminated by gasoline then the PVC will absorb and desorb the gasoline and contaminate the water inside the pipe.
2007-12-11 01:32:47 · answer #3 · answered by Tim C 7 · 0⤊ 0⤋
Water: -permeable: it means that water can go through it; like tinny "tunnels" in the rock -porous: it means that water can sit in this rock; there are only holes that don't connect, no "tunnels" Example: -permeable: natural chalk -porous: pumice
2016-04-08 08:10:36 · answer #4 · answered by Anonymous · 0⤊ 0⤋
porous material has holes large enough for molecules to pass by, like fiber insallation. Permeable membranes allow liquids or gasses to actually pass through, like water through cell walls.
2007-12-11 01:33:28 · answer #5 · answered by Bumblebee 4 · 0⤊ 0⤋
Again, tlbs101 is exactly correct. Porosity is that amount of "empty space" within a material and permeability is the ability for flow to pass throug hthe material.
2007-12-11 02:34:14 · answer #6 · answered by Anonymous · 0⤊ 0⤋
porous lets water through, permeable does not.
2007-12-11 01:28:16 · answer #7 · answered by matrix 3 · 0⤊ 2⤋
Porosity is defined as the proportion in per cent of the total volume of a body of bedrock or regolith that cosists of open spaces.
Permeability is defined as the capacity of a material for transmiting fluids.
2007-12-11 02:21:58 · answer #8 · answered by tomjc43 7 · 2⤊ 0⤋
Tlbs 101 has the absolute right answer and the best explained answer.
2007-12-11 02:29:46 · answer #9 · answered by oil field trash 7 · 1⤊ 0⤋