Sunday, 30 January 2011
Can you make an image appear from nowhere?
Wave the wand up and down rapidly over the line marked on the table.
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 the light sufficiently.