phenakistoscope

The phenakistoscope, from Greek roots meaning appearance observer, is an early optical toy and animation device that created the illusion of motion from a sequence of pictures. It was invented in 1832 by Belgian physicist Joseph Plateau, with independent development by Austrian physicist Simon von Stampfer. The device helped popularize the idea that motion could be perceived through persistence of vision.

A typical phenakistoscope consists of two main parts mounted on a common axis: a circular disc printed with a strip of pictures showing consecutive phases of a motion, and a second thinner disc with evenly spaced slots. The discs rotate together; the user holds the device in front of a mirror and looks through the slots at the images reflected on the opposite face of the first disc. As the pictures align with the viewer’s eye in rapid succession, the brain blends them into a short animated sequence.

The phenakistoscope was widely produced in the 1830s and inspired various designs and discs. The name derives from Greek roots meaning to appear and watcher. It is one of the earliest devices to produce moving pictures and a direct ancestor of later animation devices such as the zoetrope and the praxinoscope. The phenomenon it demonstrates—persistence of vision—remained central to the development of modern animation and cinema.