Why do edges curl when knitting?

What is Purlwise in knitting?

To slip a stitch purlwise, you insert your needle into the next stitch as if to purl, and just slide it from your left needle to your right needle. To slip a stitch knitwise, insert your needle as if to knit, and then slip that from your left needle to your right needle.

IT IS INTERESTING:  Frequent question: Does Stitch Fix offer nursing clothes?