Why do some clothes shrink after washing and why do some clothes stretch in the wash?



Does it depend on the fabric? If a shirt shrinks can you wash is more until the fabric stretches?

In: Chemistry

Depends on the fabric. Wool, for example, is rough in one direction but smooth in the other, like your hair. Pluck out a strand of hair and you’ll see that it is easy to stroke it in one direction but more difficult to stroke it in the other. Basically that means the fibers of wool fabric can only move in one direction.

So when you jostle those fibers around, causing them to rub against each other, you’re essentially ratcheting them closed and closer together. This is exacerbated with water and heat, which makes the fibers swell and more flexible, increasing points of contact.

For fabric that doesn’t do this, then the simple agitation of the fabric in a washer will wear the fibers down, causing them to stretch.