Wool Fibres Have Scales That Lock Together
Wool is the fleece of sheep. Its microscopic scales explain both its warmth and its shrinking.
Wool is the soft curly hair forming the fleece of sheep. Each fibre is covered in overlapping scales, like roof tiles, and that structure explains two things at once: it lets fibres grip each other so wool can be spun without adhesive, and it makes wool felt and shrink when hot water and agitation push the scales into a permanent tangle. Machine washing does exactly what felting requires. Wool also absorbs up to a third of its weight in moisture while still feeling dry.
- Sheep's fleece. *Pure wool.*
- Woollen. *A woollen jumper.*
- To felt. *Felting wool.*
- Fleece — the whole coat. *A fleece.*
- Old English — *wull*. *The source.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | wool | Wool. |
| Adjective | woollen | Woollen. |
| Adjective | woolly | Woolly. |
| Related | fleece | A fleece. |
| Latin | lana | Wool. |
- A wool coat.Fabric.
- Hot water felts it.Care.
- Pull the wool over his eyes.Idiom.
Why wool shrinks
- Each fibre is covered in overlapping scales
- Heat and moisture make the scales open
- Agitation pushes fibres past each other
- The scales catch and cannot slide back
- The result is felting, which is irreversible
Old English *wull*, of Germanic origin, related to Latin *lana* and German *Wolle*.
Why does wool shrink in the wash?
Heat and agitation open the scales on each fibre and push them into a permanent tangle, a process called felting.
Why does wool feel dry when damp?
It can absorb up to about a third of its weight in moisture inside the fibre before feeling wet.