the.com/permeability
how easily a thing lets something through, measured in barriers that aren't really barriers.
means The degree to which a material or membrane allows fluids, gases, or other substances to pass through it.
from From Latin "permeare," to pass through, built from "per-" (through) plus "meare" (to go, to pass) — the same "meare" that gives us "permeate." The abstract "-ability" suffix turned the act of passing through into a measurable property, a move that suited the language of physics and chemistry as those fields grew hungry for words describing how readily one thing moves through another.
- vacuum value
- empty space has a defined magnetic permeability
- darcy unit
- rock permeability named after a French engineer
- skin's job
- your barrier still leaks water and medication through
- capacitor cousin
- permittivity governs electric fields, permeability governs magnetic ones
- cell gatekeeper
- membranes choose what enters, life depends on selectivity
darcy's law — describes water flow through porous media; quantifies permeability coefficient in hydrogeology since 1856
blood-brain barrier — selective permeability of capillaries in the brain limiting molecule passage, studied extensively since 1900s