The zipper as we know it is barely over 100 years old, but it's the closure of choice for thousands of everyday products. Learn the history and physics behind the zipper (and why so many zipper tabs say 'YKK') in today's episode of BrainStuff, based on these articles: https://science.howstuffworks.com/innovation/everyday-innovations/zipper.htm/printable; https://home.howstuffworks.com/home-improvement/household-hints-tips/cleaning-organizing/question469.htm