The Logical Reason Why Wool Sweaters Shrink In the Wash but Sheep Don’t Shrink in the Rain

In an really interesting episode of MinuteEarth, host Kate Yoshida visually responded to a viewer who asked why, if wool clothing shrinks when it gets wet, why don’t sheep? Yoshida explained that it isn’t only water that makes the garment shrink, it’s the heat and bustle of a washer that breaks down the protective structure of the directional fibers.

Getting wet isn’t REALLY what makes wool shrink; it merely exacerbates the friction between the wool fibers, which is stronger in one direction than another, so when agitated in the washer or dryer, they migrate in relation to each other in a process called “felting.”