A wool shawl can feel remarkably warm for its weight, but a strong wind exposes the limits of that warmth. The reason is air. Held among wool fibers, it forms pockets that slow the movement of heat away from the body; when wind pushes through the fabric, those pockets are disturbed and replaced by colder air.The shawl's lightness is an advantage, not a contradiction. Wool fibers create a porous st...More