Before I get started on my real topic today, let me just say YAY, DH’s slippers are done!

Clockwise from the top, these are Mom’s, DH’s, and my slippers.

Anyway, as I was in the midst of this slipper frenzy, I started wondering about the details of how exactly this felting thing works.  I know that it happens because of the scales on the fibers surfaces interlock and tighten their association with heat and agitation.  What I didn’t know exactly was the effect that new cohesion has on the fabric.  It’s very possible that this is all well known and I somehow just missed it, but I just wanted to fool with the possibilities myself to see what I could find out.

So I knitted two squares of each of the different yarns I used for our slippers.  Specifically, DH’s and mine are of Ella Rae’s Classic Wool held double, and Mom’s is of Cascade Yarns’ Alpaca Lana D’Oro, which is 50/50 alpaca and wool.

Then I tossed one square from each yarn in the washer on hot, heavy agitation to see what would happen.  Here are my results!

The pure wool went from 7″ high x 7″ wide to 3.5″ high x 5″ wide

and the alpaca/wool blend went from 6.5″ high x 7″ wide to 4″ high x 5.75″ wide

So what I am seeing from this is experiment is that the width shrinks less than the length, and that the blend shrinks less than pure wool.  I further deduce that my next experiment will be to try this with pure alpaca, which I do have some leftovers of someplace.    Stay tuned to the fascinating story of How the Wool Shrinks!