The motion of the wand makes an entire image appear.


The wand reflects, one width at a time, sections of an image that is projected over the line. Our sensory system, however, stores the visual perception of each width for such a length of time that we effortlessly perceive the images as a single entity.

Move the wand at different speeds and notice how the speed affects your perception of the image. At what speed does the illusion of a complete image break into individual streaks of light with no meaning?

Normally, we see images projected on a screen at the movie theatre or in a lecture hall. Images can also be projected onto other materials, such as water, steam or fog, as long as they reflect light sufficiently.