Like Silly Putty, the Slinky® was an accidental by-product of World War II research and development that was transformed into a hugely successful children's toy.
In 1943, engineer Richard James of greater Philadelphia was working in his home laboratory to invent a set of springs that could be used to support sensitive instruments on board ships and stabilize them even in rough seas. When he once accidentally knocked one of his springs off of a shelf, James saw that, rather than flopping in a heap onto the floor, the spring "stepped" in a series of arcs from the shelf to a stack of books to a tabletop to the floor, where it re-coiled itself and stood upright.
After repeated experiments proved the spring's now famous ability to climb down stairs, James' wife, Betty, realized the device's potential as a plaything. She also invented a name for it: the Slinky®. In 1945, the James' first exhibited their new toy at the Gimbels Department Store in downtown Philadelphia. They sold 400 Slinkys® in 90 minutes. This was the start of a sensation that continues to this day.
The James' founded James Industries in Hollidaysburg, Pennsylvania, to market their product. Richard invented machines that could coil 80 feet of steel wire into a Slinky® in about 10 seconds. By the time of its 50th anniversary in 1995, that same company, using those same machines, had sold over a quarter of a billion Slinkys® all over the world.
In the 1940s, the Navy never took an interest in James' springs. But after their success as a toy, Slinkys® began to find practical uses. High school teachers have long used them to demonstrate the properties of waves. U.S. troops in Vietnam used them as mobile radio antennas. NASA has used them in zero gravity physics experiments in the Space Shuttle. From the playroom to the classroom, climbing down stairways and floating in space, Richard and Betty James' Slinky® continues to educate and entertain.