Book 3, Question 144
Why Do Zippers Zip?
A zipper is two toothy rails and a little slider. The slider is a Y-shaped tunnel. It meshes the teeth together on the way up, and unmeshes them on the way down!
From the book
Page from A Million Whys Book 3
More fun facts
- To zip, the two rows of teeth must line up perfectly, which is why the slider has to be fitted onto the bottom pin first.
- The mechanics of a zipper are simple, but it has to work smoothly or not at all.
- YKK was founded by Tadao Yoshida in 1934.
- Engineer Scott Peters invented a zipper that can be closed with one hand, after his mom asked for help.
- His Magzip uses magnets to snap the two halves together, and it took about 25 prototypes to get right.
- By the 1970s, YKK had overtaken the company of the zipper's inventor by working to make nearly perfect zippers.
- YKK makes about half of the world's zippers.
Sources: Smithsonian Magazine, Smithsonian Magazine
Questions kids ask
What does YKK on a zipper mean?
YKK is the name of a Japanese company that makes about half of the world's zippers.