Post-it Notes exist because a scientist failed to invent a super-strong glue.
In 1968, 3M chemist Spencer Silver was trying to make a powerful adhesive and instead produced one that was weak and could be peeled off again. For years nobody could think of a use for it.
Why is this true?
His colleague Art Fry was annoyed that bookmarks kept falling out of his church hymnbook and realised the weak glue was perfect. The notes launched nationwide in 1980, and the yellow colour was simply the scrap paper the lab had on hand.
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More about inventions
Most inventions arrive by accident, in the wrong order, or decades before anyone finds a use for them. Microwaves, sticky notes, safety glass and vulcanised rubber all started as mistakes or side effects. The facts here trace how the thing actually came about, note who noticed the accident and why it mattered, and point at a source so you can follow the full story if it hooks you.