Reading this at your desk? Chances are you have both Scotch tape and Post-it notes somewhere in your drawers. Both are made by an adhesive company, 3M, but the sticky stuff on Post-it notes was actually a mistake. In the late 1960s, a 3M chemist named Spencer Silver was trying to make a stronger, stickier glue when he created Post-it's wan, weak adhesive. This video explains that it took several years of work, plus the insight of a musical fellow chemist, for Silver to find just the right use for his new product.