If your hair drier shrunk your head to the size of a grapefruit, you’d be astounded. If your wool pants shrank in the drier, you’d be angry but not amazed.How can clothing disobey the laws of common sense, and shrink in the laundry? To understand why this happens, we need to take a closer look at the microscopic structure of natural fibers like wool. Each thready strand you can see is composed of millions of long, tangled molecules called “polymer chains.” Microscopically, these start out coiled like miniature, tangled springs, something like a mass of tangled telephone cords.These curly molecules are stretched and straightened as the wool is carded and spun.