Thaumatrope

History:

The invention of the thaumatrope, whose name means "turning marvel" or "wonder turner," has often been credited to the astronomer Sir John Herschel. However, it was a well-known London physicist, Dr. John A. Paris, who made this toy popular. Thaumatropes were the first of many optical toys, simple devices that continued to provide animated entertainment until the development of modern cinema.

How it works:

A thaumatrope is a small disc, held on opposite sides of its circumference by pieces of string. An image is drawn on each side of the disc, and is selected in such a way that when the disc is spun, the two images appear to become superimposed. To spin the disc, one string is held in a hand, and the disc is rotated to wind the string. Then, both strings are held, and the disc is allowed to rotate. Gently stretching the strings will ensure that they continue to unwind and rewind. This motion causes the disc to rotate, first in one direction and then in the opposite. The faster the disc rotates, the greater the clarity of the illusion.

Although the thaumatrope does not produce animated scenes, it relies on the same persistence of vision principle that other optical toys use to create illusions of motion. Persistence of vision is the eye's ability to retain an image for roughly 1/20 of a second after the object is gone. In this case, the eye continues to see the two images on either side of the thaumatrope shortly after each has disappeared. As the thaumatrope spins, the series of quick flashes is interpreted as one continuous image.

One example of a thaumatrope has a tree with bare branches on one side, and on the other, its leaves. When spun, the tree appears to be full of leaves. Another example has a bird on one side, and a cage on the other. When spun, the bird appears to be in its cage. The bird-cage pair of images were used on the first thaumatrope, and is the most common one seen on thaumatropes today.

What became of it:

Most pairs of thaumatrope images were pictures that did not imply motion, such as running animals or dancing people. A thaumatrope could only take two images and merge them, essentially creating one still image from two. The phenakistoscope was a great improvement on the thaumatrope, creating one moving image from several stills, and became the first optical toy to create a true illusion of motion.

Links to animations:

Animated GIFs	Bird and Dog	Flowers and Vase

Interactive (requires JavaScript- enabled web browser)	Bird and Dog, small Bird and Dog, large	Flowers and Vase, small Flowers and Vase, large

Draw a circle on a piece of cardboard (preferably white on both sides). You can use a compass or other artist's tool to make the circle - or just trace around a cup or glass that's a size you like. Use scissors to cut out the circle.

Lightly draw a guideline through the center of the circle on one side. Punch a hole in the cardboard about 1/4-inch in from both sides on the line. (This is where you'll attach the strings.)

To make a simple thaumatrope, draw a bird cage or one side of the cardboard; then flip your circle face down and draw a bird on the other side. (You can color the bird to make a livelier thaumatrope!)

Tie the ends of about two feet of string together in a knot. Thread the other end through the hole in one side of your thaumatrope and loop it back through' itself. Do the same thing with more string on the other side.

Hold the strings about three or four inches from the cardboard and twist them between your fingers to cause the disc to spin. Look at the disc. When the speed is right and the spinning is steady the bird on one side will appear to be in the cage on the other!

Get creative! Experiment with different images. Draw a horse on one side and a man on the other to make the man appear to be riding the horse. Or the top half of a person on one side and the bottom half on the other. Spin your thaumatrope to a whole person. Draw a juggler on one side and balls the air on the other; tree on one side and leaves the other; a bald man on one side and a wig on the other. Have fun creating "half images" that make interesting "wholes" when you spin your thaumatrope. Write and tell us what clever ideas and images you created!

Other thaumatropes to try:

Side 1: Students write the first 2 or 3 letters of their name Side 2: Students write the remainder of name (upside down)

Side 1: Have students bring (or make) photographs of themselves, or cut pictures out of magazines. Glue to one side of the thaumatrope. Side 2: Draw beard, hats, glasses, or grass, sky, sun, etc. (upside down).

Thaumatropes do not have to be round or rectangular! Students can also experiment with shape. Colored paper also makes interesting effects; try black paper with brightly colored chalk drawings. See some of the sample thaumatropes included in this packet.

As you begin making thaumatropes, you will quickly see that the placement of the images involves considerable understanding of spatial relations andmathematics. For this reason, thaumatropes are excellecent tools for teaching these concepts. It is also useful to incorporate thaumatropes into the curriculum by animating subjects being studied. For example, if the class is doing a unit on the desert, students could animate desert landscapes and animals. Also, persistence of vision is a perceptual phenomenon that can be studied as a part of a science unit on light or the eye. See the listing of resources at the end of this unit for suggested books on light.

Vocabulary:

Persistence of Vision: A visual phenomenon where an image is retained in the eye for a short period of time, creating an illusion of continuous motion when viewed in rapid succession.

Thaumatrope: One of the earliest motion toys, the thaumatrope can be traced to 1826, and may be even older. It consists of a disc with pictures on both sides, tied to two pieces of string. When spun, the images on the disc appear together as a single image.