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Transcript for The Art of Science

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The Art of Science: Alan 2.0

Until the movie Titanic, no one had used synthespians or digital characters in a feature film. Now, for the first time, computer pioneers have taken the process further and synthesized both speech and movement to produce Alan 2.0 -- a digital version of Alan Alda. In this episode, watch as technology history is made and go behind the scenes with Frontiers to watch the creation. Then find out what happens when he meets a digital version of himself for the first time.

Curriculum Links
Related Frontiers Shows and Activities
Introduction: At The Movies
Activity 1: Movie Magic
Activity 2: View a Spinning Disk



movies, photography




computer graphics, digitized effects



It's a digital world. From aliens to angels, ocean liners to flubber, movies increasingly rely on digital creations. As you see on Frontiers, for the first time, many extras in a feature film, Titanic, are not real people but synthespians - computer-generated actors. Before the invention of motion pictures, people viewed photographs, then stereograms (two photos viewed through a stereoscope), and then inventors began tinkering with ways to turn still images and photos into moving images. The first results were a long way from digitally enhanced movies, but even the earliest magic lanterns, rotoscopes and crude moving pictures delighted viewers with the illusion of motion.

In 1887, photographer Eadweard Muybridge pioneered photographic studies that answered fundamental questions about locomotion. His photos featured men or animals in successive stages of motion. The photos were viewed with a zoopraxiscope, a forerunner of cinematography that inspired Thomas Edison to invent the kinetoscope. In fact, Muybridge is sometimes called the "father of the motion picture." Try these low-tech activities and amuse your friends.


Did you know that the motion you observe on a movie screen (or TV) is an optical illusion? This screen magic has to do with "persistence of vision" or the holdover of images in the brain. Even though we may be exposed to a quick flash of an object, its image is retained for a short time by the visual processing center. If another image is flashed during this retention period, the brain gets tricked into "smoothing" the transition, so what we see appears to be continuous movement.

If you examined a strip of movie film, you'd observe action captured as a sequence of still frames. At a slow projection speed, you'd observe the separate images, one following another. At a faster rate of 30 frames/ second, your brain combines the frames into a fluid and continuous motion, instead of interpreting them as separate pictures.


To generate a sequence of frames, a computer artist uses photographs of an object at its beginning and ending positions. These positions form the "key frames" that enclose a motion sequence. Next, the artist instructs the computer to generate the in-between frames. As it crunches the key frame information, the computer compiles a set of intermediate actions that logically and smoothly transform the object from the start to the final key frame. Now, it's your turn to take on the role of computer.


Explore persistence of vision.

  • scrap paper
  • marker, pen or pencil
  1. Examine the two key frames shown below. They define a frame sequence in which a character's face changes.

  2. Your job is to draw the in-between frames. Create 10 frames to smooth the motion between the two key frames. When you finish, you can turn your illustrations into a flip book.

Research the action of a piston, cylinder and connecting rod. Then create a flip book that illustrates how these engine parts work.


A spinning disk or phenakistiscope is a device that produces the illusion of movement (the word means "deceitful view"). It also uses the persistence of vision to trick the brain into thinking it is seeing motion. The original spinning disk device was invented independently by two European scientists in 1832. The disk featured a number of figures drawn in successive stages of motion. This version is adapted from The Art Pack by Christopher Frayling, Helen Frayling and Ron Van Der Meer (Knopf, 1993).


Explore the illusion of movement.

  • light cardboard
  • scissors
  • modeling knife
  • round toothpick or other device for the axle
  • gluestick or spray adhesive
  1. Print the disk shown here and cut it out.

  2. Use a gluestick to glue the disk onto a piece of light cardboard.

  3. When the glue is dry, carefully cut out the circle and slits between each image. Poke a tiny hole in the center.

  4. To view, hold the phenakistiscope up to a mirror at about eye level. The side with the images should face the mirror. Look through the slits as you spin the disk on the axle and watch the moving figures reflected in the mirror.

  1. Motion capture is often used as a special effect in movies and to study human movement. Try your own version of the motion capture you see on Frontiers. Wearing black pants and a black shirt, tape Ping-Pong balls (or pieces of white tape) along your arms and legs. See how your body looks under black light as you walk and move around. Try drawing a stick figure of the outline made by the glowing Ping-Pong balls.

  2. For more about motion capture and computer simulation, see the article Animating Human Motion, in the March 1998 issue of Scientific American.

  3. Would it take away from your enjoyment of a movie to know that it is peopled by digital characters?

  4. Who do you think should own the rights to a digital character?

  5. Find out more about how speech is synthesized at


Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.