I found this interesting on my useless facts

Silly Putty started as a mistake in a New Haven laboratory, and was turned into a consumer hit in the 1960s. According to engineers, Silly Putty is a self-contradiction. Chemically, it is a liquid, but it resembles a solid. The molecular structure will stretch if the structure is slowly pulled. But if tugged, it snaps apart. The toy has a rebound capacity of 75 to 80 percent, whereas a rubber ball has only about 50-percent capacity. A silicon derivative, Silly Putty won’t rot; it can withstand temperatures from minus 70° Fahrenheit to hundreds of degrees above zero. On top of all that, it picks up newsprint, which often appears sharper than the original.