James Wright, an engineer at General Electric's New Haven laboratory, may have invented silly putty in 1943 when he accidentally dropped boric acid into silicone oil. Dr. Earl Warrick, of the Dow Corning Corporation, also developed a bouncing silicone putty in 1943. Both GE and Dow Corning were trying to make an inexpensive synthetic rubber to support the war effort. The material resulting from the mixture of boric acid and silicone stretched and bounced farther than rubber, even at extreme temperatures. As an added bonus, the putty copied newspaper or comic-book print.
An unemployed copywriter named Peter Hodgson saw the putty at toy store, where it was being marketed for adults as a novelty item. Hodgson bought the production rights from GE and renamed the polymer Silly Putty. He packaged it in plastic eggs because Easter was on the way and introduced it at the International Toy Fair in New York in February of 1950. Silly Putty was a lot of fun to play with, but practical applications for the product weren't found until after it became a popular toy.
How Silly Putty Works
Silly Putty is a viscoelastic liquid. It acts primarily as a viscous liquid, though it can have properties of an elastic solid, too. Silly Putty is primarily polydimethylsiloxane (PDMS). There are covalent bonds within the polymer, but hydrogen bonds between the molecules. The hydrogen bonds can be readily broken. When small amounts of stress are slowly applied to the putty, only a few of the bonds are broken. Under these condition, the putty flows. When more stress is applied quickly, many bonds are broken, causing the putty to tear.