Face masks use capillary action
I wondered how the clay face mask I was wearing worked, why it was worth my time. Clay can absorb many times it’s own mass in liquids via capillary action (or capillary motion, or capillarity, or wicking). This falls under the laws of continuum mechanics, a subset of classical mechanics, which treats substances as a continuum rather than discrete particles.
Capillary action allows a substances to act independently and even against external forces, and to flow into narrow spaces propelled by surface tension and adhesive forces.
The clay absorbs excess sebum from the skin it comes into contact with using capillary action. Capillary action itself is not that surprising a mechanism here. But, the relative malleability of the mask allows the clay to come into contact with more surface area of the skin than say a blotting paper used for the same purpose.
Future rabbit holes: fluid vs liquid; laws and mechanics classes in physics; math and physics (a continuum operates outside of a coordinate system, lots of interesting math there to explore in terms of geometry as well as force calculations); wtf is skin care and how to active ingredients work?
