Silly Putty comes as a glob of what seems like a very plastic clay of unusual characteristics, inside of a roughly egg-shaped plastic case. When pressed on comics pages or other newspaper media, the loose ink transfers to the Silly Putty, which is then able to be stretched out, a source of amusement for many children. It is also bouncy, being a form of rubber. It breaks when given a sharp blow. When it gets too warm, it melts and becomes very sticky. Silly Putty comes in various colors, including glow-in-the-dark and metallic, and colors can be easily combined to make new shades of bounciness. Two combined colors of Silly Putty can still fit into one case, since the case is usually filled about half-full when purchased.
Silly Putty was accidentally invented by James Wright of General Electric when he dropped boric acid into silicone oil. He was looking for a substitute for artificial rubber. GE supplied the compound to researchers around the world. None found a use for it, but they all loved playing with it. It was commercialized by Peter Hodgson in 1949 after the marketing expert attended an informal "nutty putty" party.
Raw Silly Putty is available as Dow Corning 3179 Dilatant Compound. There are recipes for homemade silly putty used glue and boric acid, but these produce a compound that is different from silly putty itself which is made of silicone oil.
According to an MIT web page on inventions: