Persistence of Vision

Persistence of Vision means that when we look at a series of images on after another, but that we slightly 
different to the one before, our brains are fooled into thinking that it is a moving image. 

A form of early stop motion animation is called a 'Zoetrope'. The zoetrope worked on the same principles as the phenakistiscope, but the pictures were drawn on a strip which could be set around the bottom third of a metal drum, with the slits now cut in the upper section of the drum. The drum was mounted on a spindle so that it could be spun, and viewers looking through the slits would see the cartoon strip form a moving image. The faster the drum is spun, 
the smoother the image that is produced.