Posted on July 31, 2021
This is an update of my post published on July 31, 2010:
Born on this day in 1923 in Pennsylvania, Stephanie Kwolek became a chemist and invented poly-paraphenylene terephtalamide. You know—Kevlar!
Kwolek was working for DuPont when she invented Kevlar, which is used for bicycle tires, racing sails, mooring lines, and (famously) body armor. It is a high-strength material, especially considering its weight: Kevlar is FIVE TIMES stronger than steel, weight-for-weight.

A polymer is a natural or synthetic material made up of many (sometimes millions) of repeated units. Two examples of natural polymers are tortoise shell and amber. Plastics are polymers that humans artificially make.
Find out more about polymers.
Here is a polymer experiment using PVA glue and borax.
This experiment is a bit easier, because it combines ordinary white glue with borax.
Here is a great Kwolek quote: “All sorts of things can happen when you’re open to new ideas and playing around with things.”
Also on this date:
World Ranger Day
Author J. K. Rowling’s birthday
Uncommon Instruments Day
Anniversary of Daniel Defoe in a pillory – being pelted with flowers?!
(Last Saturday in July)
Plan ahead:
Check out my Pinterest boards for:
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August holidays
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August birthdays
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Historical anniversaries in August