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1 S C I E N C E ZOETROPE This Enrichment4You e-guide provides a brief overview of s. In this e-guide you will: Physical Science (Physics) O P T I C S *Learn Basic Information About the Development & Use of s *Make a Mechanized ENRICHMENT4YOU Published by Henrich Incorporated Copyright 2005 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form by any means, electronic, mechanical, photocopying or otherwise, without first obtaining the written permission of the copyright owner.

2 INTRODUCTION The purpose of this Enrichment4You e-guide is to provide inspiration, ideas and techniques for creating a mechanized zoetrope. In this e-guide you will read a brief overview about zoetropes and follow a step-by-step presentation with photographs on how to make a mechanized zoetrope. Do not feel limited in the selection of suggested materials. Your finished zoetrope will incorporate scientific elements from these historic optic toys. You may even use the model to create larger and smaller versions of a zoetrope. Have fun and be creative. Physical Science (Physics) TABLE OF CONTENTS 1. Brief overview of s - Pages Make a Hand held Mechanized - Pages 5-12.

3 Did You Know??? It takes 24 frames of film per second to convince your eye that something is moving on the screen. ZOETROPES A Brief Overview Invented in 1834, a zoetrope became one or the first animation devices that demonstrated the principal of persistence of vision and a popular toy during the Victorian era. The zoetrope was originally called the Daedalum or Wheel of the Devil by its inventor Englishman William Horner. William F. Lincoln, an American manufactured the device under a new name zoetrope which means wheel of life. The word is made up of two Greek words - zoa (living things) and trope (turning). A zoetrope is a cylinder that has vertical slits cut down the sides at the top. A strip of sequential pictures called the zoetrope strip feature slight changes between each image is placed inside the cylinder. As the cylinder is spun, the viewer looks through the slits. The result is the sequential images appear to be animated or come to life which is why the device was given the name zoetrope. Physical Science (Physics) 1

4 Did You Know??? The zoetrope has slots which create a stroboscopic effect. In movies and on TV there are also slots that break up the light. There are shutters in movie film that create the slots and interrupt the light from a projector bulb. When we watch TV, the images are scanned onto the television by a beam that zigzags across the screen from top to bottom. The Victorians were fascinated with all types of illusionary devices that demonstrated persistence of vision. Persistence of vision was first noted by Peter Mark Roget in Persistence of vision refers to the length of time the retina retains an image. It takes approximately one-tenth of a second for an image to be recognized by the brain. Each image we see remains, or persists, in the retina for at least one-tenth of a second. We perceive this persistence of an image as continuous light. When a zoetrope is spun, the viewer looks through the slits at the images. The slits simulate flashes of light, creating a stroboscopic effect. A stroboscopic effect is caused by a synchronized rapidly flashing light to make moving objects appear stationary. In order for the images to appear to move, they must be interrupted by periods of darkness. The faster a zoetrope spins, the smoother the movement of the images appear. Silent movie projects ran at 16 to 18 frames per second, present day film projects operate at 24 frames per second and VCR s play at 30 frames per second. If a zoetrope spins too quickly, the images appear as a blur - too slow, and the illusion of movement is lost. s were a fun optical toy that also employed the phi phenomenon. According to the Wikipedia free encyclopedia: The phi phenomenon is a perceptual illusion described by Max Wertheimer in his 1912 Experimental Studies on the Seeing of Motion, in which a disembodied perception of motion is produced by a succession of still images. In discussions of the perception of film and video it is often confused with beta movement, but it is a distinct phenomenon not directly involved in the perception of motion pictures. Physical Science (Physics) 2

5 Did You Know??? M. C. Escher is one of the best known optical illusion creators. His intersecting and changing images are works of art, but also works of science and math. Escher created metamorphing tessellations. These optical designs changed and interacted with each other in the drawing. When several images are placed in close proximity to one another such as on a zoetrope strip and then rotated within the cylinder, the phi phenomenon is demonstrated. Today, when we watch a movie, we are experiencing the phi phenomenon as well. An interesting side to both zoetropes and the phi phenomenon is the relationship of color to movement. This illusion of movement became part of the Gestalt school of psychology which looked at how people perceived their world. Another interesting effect is afterimages. These can occur in both colored, black & white and moving patterns. Afterimages always take place when an opposite color is present. For example, black and white, red and green. An afterimage is what we still see after an image is no longer present. If you close your eyes after seeing an image, especially one that has strong contrast such as black and white, even when your eyes are closed you can still see a ghost image. Physical Science (Physics) 3

6 Some image subjects for the zoetrope: frames can include any of the following and be very effective in showing movement. Bouncing Ball - the ball moves up and down over 6 to 12 frames showing a path of movement. Walking - Whether animal or human showing the repeated movement of the figure over 12 frames is an easy and effective motion. Metamorphosis - Show how an insect or animal changes from one stage to another such as a caterpillar to a butterfly, tadpole to a frog or an egg into a flying bird are excellent subjects for a phenakistoscope. Shape Change - an image morphs into another shape. For example, a square changes into a circle, a rectangle changes into a diamond and easy and fun subjects to consider. Morphs are best viewed as up and down animations. To change one image into another the following should be considered: 1. Images with similar shapes morph the best. 2. Keep the background constant. 3. Keep the position of the image consistent in location so it morphs on top of the previous image. Physical Science (Physics) 4 4. Keep the images being morphed sharp and clear and bold. Avoid a lot of thin lines or highly detailed work. 5. Most morphing requires a minimum of 8 frames to transition from one image into another. Other Events - an erupting volcano, a smiling face, a jet flying, the sun rising and setting are good subjects for animation. HELPFUL HINT: Look at How to books on drawing simple shapes for inspiration. Many show how to draw an image from start to finish. If there are less or more than 12 steps, make small changes in the images to adjust or add to the required number of frames.