The Slinky is a helical spring toy invented and developed by American naval engineer Richard T. James in 1943 and successfully demonstrated at Gimbels department store in Philadelphia on November 27, 1945.

[1] It can perform a number of tricks, including travelling down a flight of steps end-over-end as it stretches and re-forms itself with the aid of gravity and its own momentum; and appearing to levitate for a period of time after it has been dropped.

In 1943, Richard T. James, a naval mechanical engineer, observed a spring "stepping" downward after being knocked off a shelf, then coming to rest in a vertical position.

[2][3] James's wife Betty later recalled, "He came home and said, 'I think if I got the right property of steel and the right tension, I could make it walk.

'"[4] James experimented with different types of steel wire over the next year, and finally found a spring that would "walk".

Betty was skeptical, but changed her mind when the toy was fine-tuned and neighborhood children expressed an excited interest in it.

[3] Richard and Betty formed James Industries and began manufacturing slinkys in Clifton Heights, Pennsylvania, selling them for $1 each.

It has, however, remained modestly priced throughout its history as a result of Betty James' concern about the toy's affordability for less affluent customers.

In addition to its use as a toy, it has been used as a classroom teaching tool; as a portable and extendable radio antenna in wartime (particularly the Vietnam War).

[8] In 1960, after his wife filed for divorce, Richard James left the company and he became an evangelical missionary in Bolivia with Wycliffe Bible Translators.

When set in motion on a stepped platform such as a stairway, the Slinky transfers energy along its length in a longitudinal wave.

[16] When the top end of the Slinky is dropped, the information of the tension change must propagate to the bottom end before both sides begin to fall; the top of an extended Slinky will drop while the bottom initially remains in its original position, compressing the spring.

Should this phenomenology extend to very light strings with heavy suspended masses (which have approximately linear tension distributions), different mathematics would be needed to explain the phenomenon.

[citation needed] The jingle for the Slinky television commercial was created in Columbia, South Carolina in 1962 with Johnny McCullough and Homer Fesperman writing the music and Charles Weagly penning the lyrics.

It is seen in the "Log" commercial on The Ren & Stimpy Show and sung by actor Jim Carrey in Ace Ventura: When Nature Calls.

[20] Early in the history of James Industries, Helen Herrick Malsed of Washington state sent the company a letter and drawings for developing Slinky pull-toys.

Malsed received royalties of $60,000 to $70,000 annually for 17 years on her patent for the Slinky pull-toy idea, but never visited the plant.

[21] In 1995, the Slinky Dog (voiced by Jim Varney and Blake Clark) was redesigned for all of Pixar's Toy Story movies.

They were marketed in the 1970s as a safer alternative to metal Slinkys as they did not present a hazard when inserted into electrical sockets.

Reum came up with the idea as he was experimenting with different techniques to produce a spiral hose for watering plants.

[24] The Slinky was inducted into the National Toy Hall of Fame in 2000 in their Celebrate the Century stamp series.

A bill to nominate the Slinky as the state toy of Pennsylvania was introduced by Richard Geist in 2001 but not enacted.

[25] The same year, Betty James was inducted into the Toy Industry Association's Hall of Fame.

This is done by holding up a Slinky in the air and striking one end, causing a metallic sound that sharply lowers in pitch.

[27] The Helixophone is the name composer and artist Sonia Paço-Rocchia gave to a musical instrument made with a Slinky and a resonator.

This setup had many advantages over a long wire shot from M79 grenade launcher: small dimensions, fast and quiet installation, reusability, good takeoff angle for local communication, and adequate performance.

The video was prepared to stimulate interest in school children about the basic principles of physics and the phenomenon of weightlessness.