Zoetrope - Invented in the
1860s, the zoetrope
was a small instrument which gave drawings the
illusion of movement. Consecutive drawings
were placed on a strip of paper, which was then
placed inside a drum on which slots had been
cut. When one spun the drum and looked
through the slots, one got the impression that the
characters in the drawings were moving. The
physical concept is persistence of vision,
whereby the brain is not quick enough to see the
drawings speeding by, so they blur together and
seem to move. It was the same concept of
persistence of vision that three decades later led
to the invention of motion picture film.