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Praxinoscope

Praxinoscope is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Praxinoscope rather than just read about it. In short: The praxinoscope is an animation device, the successor to the zoetrope. It was invented in France in 1877 by Charles-Émile Reynaud.

Praxinoscope — main illustration
Praxinoscope — illustration

Key takeaways

  • Praxinoscope belongs to physics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Praxinoscope to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Praxinoscope from memory before moving on to harder problems.

Reference excerpt

The praxinoscope is an animation device, the successor to the zoetrope. It was invented in France in 1877 by Charles-Émile Reynaud. Like the zoetrope, it uses a strip of pictures placed around the inner surface of a spinning cylinder. The praxinoscope improved on the zoetrope by replacing its narrow viewing slits with an inner circle of mirrors, placed so that the reflections of the pictures appeared more or less stationary in position as the wheel turned. Someone looking in the mirrors can, therefore, see a rapid succession of images producing the illusion of motion, with a brighter and less distorted picture than the zoetrope offered.

Precedents The author of the first retinal resistance theory was Joseph Plateau, who, in 1832 invented the first Phenakistiscope which consisted of a cardboard disk which’s perimeter was holed by equidistant radiants that carried the drawings that represented the different phases of a circular motion. If the eye was disposed at the same height as the hole was during the fast circular motion of the disk, it created the illusion of movement. Almost at the same time, Simon Stamper invented the Stroboscope, which was only differentiated by the separation of the holes and the drawings made from two different disks which rotated in different directions. Finally, the most famous invention, previous to the creation of the first Praxinoscope, was the zoetrope, developed by William George Horner in 1834. The holes in this invention were on top of the black cylinder, and the drawings were disposed thorough a non-removable tape on the interior of the invention. Nevertheless, the greatest inconvenience these inventions had was the loss of light caused by the holes, a problem that would persist until the use of mirrors on future inventions which would help to increase the clarity of the projections.

Variations Reynaud introduced the Praxinoscope-Théâtre in 1879. This was basically the same device, but it was hidden inside a box to show only the moving figures within added theatrical scenery. When the set was assembled inside the unfolded box, the viewer looked through a rectangular slot in the front, onto a plate with a transparent mirror surrounded by a printed proscenium. The mirror reflected a background and a floor that were printed on interchangeable cards placed on the inside of the folded lid of the box, below the viewing slot. The animated figures were printed on black strips, so they were all that was visible through the transparent mirror and appeared to be moving within the suggested space that was reflected from the background and floor cards. The set appeared with 20 strips (all based on previous standard praxinoscope strips), 12 backgrounds and a mirror intended for background effects for the swimming figure. This set also sold very well and appeared in slight variations, including a deluxe version made of thuja-wood with ebony inlays. Reynaud mentioned the possibility of projecting the images in his 1877 patent. He presented a praxinoscope projection device at the Société française de photographie on 4 June 1880, but did not market his praxinoscope a projection before 1882. Only a handful of examples are known to still exist. In 1888 Reynaud developed the Théâtre Optique, an improved version capable of projecting images on a screen from a longer roll of pictures. From 1892 he used the system for his Pantomimes lumineuses: a show with hand-drawn animated stories for larger audiences. It was very successful for several years, until it was eclipsed in popularity by the photographic film projector of the Lumière brothers.

The praxinoscope was copied by several other companies. Ernst Plank offered several variations, including one that was automated by a small hot air engine.

Movement of a Praxinoscope The movement a praxinoscope develops, consists of a sequence of movements where the same action is repeated all over again in a circular motion, just to activate and deactivate the mechanism of the object. In this kind of optical inventions, the way the object is perceived and how it is manipulated becomes a crucial part of the process. The eye of the spectator should become static so that the movement can happen right how it should. This movement is regulated by the person who activates the sequence.

Simple Harmonic motion This movement describes a force which is proportional to the distant the images are travelling. The movement generates a repetition every specific time period. This movement will only be considered Simple Harmonic motion if the force that generates the movement is proportional to the distance travelled by the images.

Uniform circular motion The uniform circular motion represents the movement an object makes, maintaining a constant speed in a circular motion. There are two speeds to consider: the velocity of the movement of the object, and the speed in which the turning angle varies. Even though the speed of an object may be constant, its velocity may not: velocity is a vectorial magnitude, tangent to the trajectory, which means in every instant it changes direction.

20th-century revival The Red Raven Magic Mirror and its special children's phonograph records, introduced in the US in 1956, was a 20th-century adaptation of the praxinoscope. The Magic Mirror was a sixteen-sided praxinoscopic reflector with angled facets. It was placed over the record player's spindle and rotated along with the 78 rpm record, which had a very large label with a sequence of sixteen interwoven animation frames arrayed around its center. As the record played, the user gazed into the Magic Mirror and saw an endlessly repeating animated scene that illustrated the recorded song. In the 1960s, versions of the Red Raven system were introduced in Europe and Japan under various names—Teddy in France and the Netherlands, Mamil Moviton in Italy, etc.

Etymology The word praxinoscope derives from the Greek combining forms praxi- (from πρᾶξις, “action”) and -scope (from σκοπέω, “to look at”).

See also Electrotachyscope History of film Strobe light Zoopraxiscope

References

External links

A picture and further information Praxinoscopes: Kenyon College Department of Physics A demonstration of this and similar optical toys, including the zoetrope The Influence of Emile Reynaud More on Reynaud's Théåtre Optique

Illustrations

Praxinoscope: An 1879 illustration of a praxinoscope
An 1879 illustration of a praxinoscope
Praxinoscope: A projecting praxinoscope, 1882
A projecting praxinoscope, 1882
Praxinoscope: The Théâtre Optique, 1892. This ultimate elaboration of the device used long strips with hundreds of narrative images.
The Théâtre Optique, 1892. This ultimate elaboration of the device used long strips with hundreds of narrative images.
Praxinoscope: The kinematofor made by Ernst Plank, of Nuremberg, Germany: a variation of the praxinoscope, powered by a miniature hot air engine.
The kinematofor made by Ernst Plank, of Nuremberg, Germany: a variation of the praxinoscope, powered by a miniature hot air engine.

Worked examples

Example 1 — a first encounter with Praxinoscope

Start with the simplest possible case. Write down what Praxinoscope claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Praxinoscope before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Praxinoscope ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Praxinoscope

In research
Praxinoscope appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Praxinoscope in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Praxinoscope is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1870s in animation, Audiovisual introductions in 1877, French inventions, so understanding it makes those chapters shorter.
In everyday life
Look for Praxinoscope outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Praxinoscope in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Praxinoscope means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Praxinoscope out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Praxinoscope in simple terms?

The praxinoscope is an animation device, the successor to the zoetrope. It was invented in France in 1877 by Charles-Émile Reynaud.

Why does Praxinoscope matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Praxinoscope?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Praxinoscope.

Tags

  • 1870s in animation
  • Audiovisual introductions in 1877
  • French inventions
  • Optical toys
  • Precursors of film

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