Did you know the Slinky was invented in 1945 by a Naval Engineer? This article from About.com gives a history of the slinky. Apparently the engineer was working on developing a meter that would monitor horsepower on naval battleships when he discovered the way the tension springs he was working with kept moving after they fell to the ground. As the story goes, "Richard remarked to his wife Betty, 'I think I can make a toy out of this'" and the Slinky was born. Along with the article are links to more interesting facts about slinky history, a letter from Betty James (his wife) and the physics and workings of spring coils (using Hooke's Law). Dont' miss the animated version of a slinky in motion -- it almost put me in a trance!