In 1968, while conducting experiments with adhesives for aerospace use, Spencer Silver, a research scientist at the company 3M, inadvertently invented a formula for a removable and reusable adhesive. Made with tiny, “pressure-sensitive” spheres of acrylic, the adhesive is strong enough to hold two pieces of paper together but weak enough to withstand the papers’ being repeatedly pulled apart.
This formula was not utilized until many years later, when Art Fry, a product development researcher at 3M, used it to solve a problem. When Fry sang in his church choir, he kept losing his place in his hymnal. To combat this problem, he combined Silver’s adhesive with paper and made a reusable bookmark. In 1980, five years after Fry had presented his story to the company, 3M manufactured Post-it notes, pads of paper bound by the reusable adhesive, that have now become ubiquitous in schools, offices, and homes. While the original Post-it note was small yellow square, they are now produced in over 62 colors and many different sizes, shapes, and varieties to suit a variety of tasks and needs.