The Thaumatrope

posted on 10 Jun 2013 by guy
last changed 23 Oct 2013

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ages: 5 to 10 yrs
budget: $0.00 to $0.00
prep time: 0 to 15 min
class time: 10 to 20 min

This lesson contains plans and materials for constructing a thaumatrope, a Victorian era animation toy that blends two images together by making use of human persistence of vision. All that's needed is an index card and some string.

required equipment: index card, string
subjects: Biology, Psychology
keywords: thaumatrope, animation, persistence

file attachment(s): 



Fig. 1: Victorian thaumatrope of a dog and birds. Click on the thumbnail image to jump to an animation by Dahl Clark at the North Carolina School of Science and Mathematics.

history

In 1827, the English physician John Ayrton Paris published a book entitled Philosophy in Sport Made Science in Earnest, which he described as "an attempt to illustrate the first principles of natural philosophy by the aid of the popular toys". In that book he introduced the thaumatrope, a toy probably based on ideas from the famous astronomer John Herschel.

In the thaumatrope, a card with an image on each side is attached to a string or thin stick. When the card is spun rapidly using the string, the images on both sides appear to blend together. The toy was popular during Victorian times, and several examples survive, including the thaumatrope in figure 1. Click on the thumbnail image to jump to an animation of the thaumatrope by Dahl Clark.

In 2012, Marc Azéma, an archeologist specializing in cave art at Université de Toulouse-Le Mirail and Florent Rivère published an article1 that suggested that some artifacts found in the Pyrenees might be examples of paleolithic thaumatropes: a sandstone plaque and some bone disks showing images on both sides, with holes where strings might have been attached. A video of some of their work is shown below. If their hypothesis is correct, Dr. Paris was scooped by more than 10,000 years.


Video by Marc Azéma showing examples of possible paleolithic animation.


Put the fish in the bowl. Video of a modern thaumatrope by Rose Saint-Marie.

construction

The video above by Rose Saint-Marie shows an excellent example of a modern thaumatrope. The thaumatrope is easy to construct, and requires nothing more than a stiff card and a couple of pieces of string or rubber band. Draw two images, one on each side of the card, which will blend together to make a complete scene. If the card is to be twirled along the horizontal axis, one image must be upside down relative to the other. Attach strings or rubber bands at the sides and use them to make the card spin.

Don't want to draw your own? The attached file includes an image based on Leonardo da Vinci's Vitruvian Man that can be attached to an index card to make a thaumatrope. Print the image without scaling; cut it out and fold at the center line. Use rubber cement to glue it to both sides of a 3 by 5 index card. Punch holes where indicated and attach two loops of string for handles. Wind up the string and pull to get the card to spin.

how it works

When the two images of a thaumatrope are presented in quick succession, the images seem to blend together because of the persistence of human vision. As light strikes the retina, it causes electrochemical signals to be sent to the brain for processing. These signals continue for a short while, 15 to 30 milliseconds, even after the light stops. As a result, we perceive an image for a short while even after the image disappears. That short persistence time is enough for our visual systems to process the two sides of a thaumatrope together, and perceive them as a single view. See our lesson on Positive Afterimages for more details on visual persistence.

further resources

Dahl Clark at the North Carolina School of Science and Mathematics has put together a very nice site covering a variety of optical toys, including the thaumatrope.


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