The zipper might be the most underappreciated of all the gadgets we use every day. Without it our trousers, jackets, suitcases and wallets wouldn’t close. And I have to admit, until writing this article I’d never stopped to consider how a zipper really works. Now I know how simple it is, it’s kind of thrilling.
The two sides of a zip have to be positioned so the tiny metal teeth slip in-between the teeth of the opposing side. One side’s teeth are slightly hollowed and the other slightly hooked, so when they slide together they fasten. The magic happens inside the slider: an internal wedge angles the teeth together as it does up, and the narrow end separates them as it slides back down.
