A rocking chair or rocker is a type of chair with two curved bands (also known as rockers) attached to the bottom of the legs, connecting the legs on each side to each other. The rockers contact the floor at only two points, giving the occupant the ability to rock back and forth by shifting their weight or pushing lightly with their feet. Rocking chairs are most commonly made of wood. Some rocking chairs can fold. Etymology The word rocking chair comes from the verb to rock. The first known use of the term rocking chair was in 1766. Purpose Rocking chairs are often seen as evocative of parenting, as the gentle rocking motion soothes infants and sends them off to sleep. Many adults find rocking chairs soothing because of the gentle motion. Gentle rocking motion has been shown to provide faster onset of sleep than remaining stationary, mimicking the process of a parent rocking a child to sleep. Rocking chairs are also comfortable because, when a user sits in one without rocking, the chair automatically rocks backward until the sitter's center of gravity is met, thus granting an ergonomic benefit with the occupant kept at an un-stressed position and angle. Varieties of rockers include those mounted on a spring base (or platform) called "platform rockers" and those with swinging braces commonly known as gliders. History Though American inventor Benjamin Franklin is sometimes credited with inventing the rocking chair, historians actually trace the rocking chair's origins to North America during the early 18th century, when Franklin was a child. Originally used in gardens, they were simply ordinary chairs with rockers attached. It was in 1725 that early rocking chairs first appeared in England. The production of wicker rocking chairs reached its peak in America during the middle of the 18th century. These wicker rockers, as they were popularly known, were famous for their craftsmanship and creative designs. Rocking cradles long predate rocking chairs however and an example exists from antiquity, found in the ruins of Herculaneum. During the 1830's Peter Cooper American industrialist and inventor designed the first steel chair in America which was a rocking chair, and exhibited at Crystal Palace Exhibition in 1851. Michael Thonet, a German craftsman, created the first bentwood rocking chair in 1860. This design is distinguished by its graceful shape and its light weight. These rocking chairs were influenced by Greek and Roman designs