What is "thaumatrope"

Thaumatrope \Thau"ma*trope\ (th[add]"m[.a]*tr[=o]p), n. [Gr. qay^ma a wonder + tre`pein to turn.] (Opt.) An optical instrument or toy for showing the persistence of an impression upon the eyes after the luminous object is withdrawn.

Note: It consists of a card having on its opposite faces figures of two different objects, or halves of the same object, as a bird and a cage, which, when the card is whirled rapidly round a diameter by the strings that hold it, appear to the eye combined in a single picture, as of a bird in its cage.

n. A toy made of a card with an image on each side; when twirled, the images combine

A thaumatrope is an optical toy that was popular in the 19th century. A disk with a picture on each side is attached to two pieces of string. When the strings are twirled quickly between the fingers the two pictures appear to blend into one due to the persistence of vision.

Thaumatropes can provide an illusion of motion when two stages of a figure in motion are depicted, but no examples are known to have been produced before the introduction of the first widespread animation device: the phénakisticope.

Examples of common thaumatrope pictures include a bare tree on one side of the disk, and its leaves on the other, or a bird on one side and a cage on the other. They often also included riddles or short poems, with one line on each side.

Thaumatropes are often seen as important antecedents of motion pictures and in particular of animation. This is partly due to many film historians' belief that the associated theory of persistence of vision explains the physiological basis for movies, although this was disproved in 1912.