Optical illusion presentation. Optical illusion presentation Optical illusion presentation optical illusion

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Optical illusions or optical illusion

First, the retinal image is inverted. Secondly, due to the imperfect optical properties of the eye, the picture on the retina is defocused or blurred. Third, the eye is in constant motion. Thus, the image is in constant dynamics. Fourth, the eye blinks about 15 times per minute, which means that the image stops being projected onto the retina every 5-6 seconds.

These are errors in visual perception caused by inaccuracy or inadequacy of the processes of unconscious correction of the visual image (incorrect assessment of the length of the segments, the size of the angles or the color of the depicted object, illusion of movement, "illusion of the absence of an object" - banner blindness, etc.), as well as physical reasons ( "Flattened moon", "broken spoon" in a glass of water). The reasons for optical illusions are studied both when considering the physiology of vision and in the study of the psychology of visual perception. What are optical illusions?

This is a vertical-horizontal illusion. Both lines are the same length, but the vertical line appears to be longer than the horizontal one. The Wundt-Fick illusion or the inverted "T" (1851)

Ebbinghaus-Titchener illusion (1902) Contrast illusion An illusion in which the same object is perceived as larger among small background objects and smaller among large background objects To make sure that the circles are the same, of course, you can use a ruler, but you can also without her. Close one eye and look at a conditional point in the middle between the circles. A few seconds later, you will see that they are the same.

Variants of the Ebbinghaus-Titchener illusion

Müller-Lyer illusion (1889) The illusion is that one of the arrows visually appears to be longer than the other, although in both cases the arrow lines are exactly the same length. Which arrow is longer?

Müller-Lyer illusion variants

Long parallel lines crossed by a series of short diagonal lines appear to diverge. Zölner noticed this illusion in 1860 by accident while examining the fabric. Zöllner's Illusion (1860) Do these lines diverge? They are parallel

Zöllner illusion variant

This illusion is also called "false spiral" or "coiled rope". The spiral is formed by twisted veins (ropes) of different colors and, in fact, is a concentric circle. Fraser's Illusion and Fraser's Spiral. Do you think this is a spiral?

Fraser's illusion variant

The two objects appear to be different in size, although, in fact, they are exactly the same. Jastrow's Illusion (1891)

Pinn-Brelstaff illusion Concentrate on the center of the drawing. Get closer to the screen, then back - the circles will begin to rotate towards each other.

Pinn-Brelstaff illusion variant

Illusion Leviant (1984) If you look at the center of the picture, after a while the circles begin to flicker and then rotate.

Look at the center of the left picture. Does it flicker and rotate? Now move your gaze to the center of the right drawing, then again to the center of the left. ATTENTION! All pictures presented here are absolutely static. Any movement seen is an illusion.

The illusion of a rubber pencil Take a pencil in your hand (you can also use a fountain pen) and shake it as fast as possible, as shown in the picture. The illusion is created that the pencil is bent as if it were rubber.

The blue line seems to be tilted left and down and even curved, although, in fact, it is strictly horizontal. Cafe Wall illusion

In 1979, Dr. Richard Gregory noticed this curious effect on the wall of a cafe in Bristol. Hence the name of the illusion.

Wall illusion option

These wheels only spin in your imagination.

These birds do not fly.

Another example of movement.

Does the image seem to be pulsing?

Does it seem like a wave is going along the pattern?

All lines are parallel and perpendicular.

All red lines are parallel

All lines are parallel and the squares are equal.

So, illusions are an integral part of any perception, which only deals with comparing them with reality. There are many scientific directions that, using various experimental techniques, try to understand how we perceive the world around us.

Powerpoint presentation on "Optical illusions" in physics. An interesting presentation for schoolchildren contains a large number of examples of optical illusions, it also tells what optical illusions are and the main reasons for their occurrence. Author of the presentation: Ostrozhnaya Elena Vladimirovna, physics teacher.

Fragments from the presentation

What are optical illusions

The main reasons for optical illusions

The first reason is that the visual system perceives light reflected from objects in such a way that the human consciousness receives erroneous (imaginary) information.
the second reason is the erroneous, incorrect transmission of vision signals through the nerves, as a result, the brain also receives incorrect information, which leads to an imaginary, distorted perception.
the third reason is based on brain disorders (malfunctions of brain activity), which gives an incorrect reaction.
In some cases, an illusion can arise for several reasons at once.

Types of optical illusions

Visual distortion
Apparent figures
Impossible figures
Inverted pictures
Dual images
Pareidolic illusions
Illusions of movement
Illusions of color and contrast
Depth perception illusions

Visual distortion

Hering's illusion (fan illusion)
Illusion Cafe "Wall"
Perelman's illusion
Pencil in water
Circles or spirals

Pareidolic illusions

Pareidolic illusions- illusory perception of a real object
This play of light and shadow gave rise to many ufological theories about ancient Martian civilizations. No face is detected in later photographs of this region of Mars.

Illusions of movement

Look at the black dot in the center and, without taking your eyes off, move your head back and forth; the circles around the dot will begin to move.

Illusions of color and contrast

Goering lattice. At the intersections of all white stripes, except for the intersection where you are currently fixing your gaze, small gray spots are visible.
The illusion of a shimmering grid. White circles seem to be flashing, don't they?

Depth perception illusions

Strange workers.
Asphalt illusions

This is without a doubt the best illusion.

Relax and watch uninterruptedly for 30 sec. 4 small dots in the center.
Then slowly move your gaze to the wall (or something large and monochrome) near you.
You will see how a light circle is formed.
Blink a couple of times and you will see how a figure is formed in this circle.
What or who do you see?

Lev Tolstoy

Mona lisa

Concentrate your gaze on the red dot in the center of the drawing for about 30 seconds. Then close your eyes and turn your head towards the sky or light ... Did you recognize?

Che guevara

Concentrate your gaze on the red dot in the center of the drawing for about 30 seconds. Then close your eyes and turn your head towards the sky or light ... Did you recognize?

Optical illusions 8th grade

Borisova Irina Dmitrievna,

Physics teacher,

BOU of Omsk "Secondary school number 101"

“Through the eye, not the eye the mind knows how to look at the world ”William Blake.

Light, refracted in the optical system of the eye, which is formed by the cornea, lens and vitreous body, gives on the retina real, reduced and reverse images of the objects in question. Once on the endings of the optic nerve. of which the retina is made, light irritates these endings.

These stimuli are transmitted to the brain along the nerve fibers, and a person has a visual sensation: he sees objects.

The image of an object that appears on the retina is inverted (I. Kepler).

? Why, then, do we see all things as they are?

Visual distortion
Size perception illusions
Color and contrast
Apparent figures
Depth perception
Shifters
Pattern recognition
Figure and background

In fact, all impossible figures can exist in the real world.

So, all objects drawn on paper are projections of three-dimensional objects, therefore, you can create such a three-dimensional object that, when projected onto a plane, will look impossible.

When looking at such an object from a certain point, it will also look impossible, but when viewed from any other point, the effect of impossibility will be lost.

The most famous impossible figures are the impossible triangle, the endless staircase and the impossible trident.

The impossible figures gained wide popularity thanks to the lithographs of the Dutch artist M.K. Escher.

The direction in the visual arts, aimed at depicting impossible figures, is called imp-art.

Escher's cube

How many dinosaurs are there?

Impossible transformer

How many legs does an elephant have?

Amazing seating

Impossible wheel

The illusion of perception

Our brain builds distorted images of reality. He is able to create the appearance of something that does not exist in reality and at the same time not notice the obvious.

We can observe some phenomenon, even knowing that it is impossible.

In psychology, this is called the illusion of perception.

IN There are two types of illusions - those based on certain physical conditions, and those that are psychologically conditioned.

Examples of the first type of illusion are mirages or distortion of objects when they are perceived in water or through a prism. The explanation for such illusions lies outside of psychology. There is more physics here.

Illusions of the second type are associated with the peculiarities of perception, for example, geometric figures, when their proportions, colors, etc. are distorted in visual images.

This is more physiology and psychology.

More examples of well-known illusions.

The rails on the railway are parallel and located at some distance from each other. Nevertheless, if we look into the distance, we see that they supposedly converge to the horizon.

Electric or telegraph poles of the same height. But those in the distance seem small compared to those near.

We are generally accustomed to the fact that all objects receding to the horizon decrease on the retina in their linear dimensions: people, trains, clouds, airplanes.

Size perception illusions

They are connected with the fact that the same lengths in the horizontal and vertical position or in the presence of additional elements seem to be different.

BUT). Müller-Lyer illusion. Which horizontal line is longer? It seems like the top one. In fact, they are equal.

B). Picture tube illusion. Which of the red lines is longer? It seems to be right. No, they are the same length.

The Nick Williams Illusion (1996)

In the upper picture, there is just a mask of an Egyptian mummy (2-2.5 thousand years BC). On the middle - the same mask, but from the inside.

At the bottom - an enlarged part of the reverse side of the mask. Notice how difficult it is to perceive this image as concave.

The brain unconsciously sees this face as normal.

IN). Ebbinghaus illusion.

Which circle is bigger?

The one surrounded by small circles or the one surrounded by large ones? It seems the one that is small.

No, they are the same.

Shifters

A shape-shifter is a type of optical illusion in which the nature of the perceived object depends on the direction of the gaze. One of these illusions is the "duck-hare": the image can be interpreted both as an image of a duck and as an image of a hare.

This is without a doubt the best illusion.

Be sure to try:

1) Relax and watch uninterruptedly for 30 sec. 4 small dots in the center.

2) Then slowly move your gaze to the wall (or something large and monochrome) near you.

3) You will see how a light circle is formed.

4) A couple of times the sea will rot and you will see how a figure is formed in this circle.

5) What or who do you see?

The effect is enhanced by tilting, rotating, moving the head closer / away

Still image appears to be moving

When looking at the same moving balls, you can see that they are of different sizes.

The same animation can depict a rotating object clockwise, counterclockwise, or alternately (oscillate).

Rubber pencil illusion

Well, lastly ...

Follow the instructions carefully.

This is amazing!

1. Place your hand on the mouse.

2. Hover the mouse over the symbol below (it is without viruses).

3. Concentrate on a point in the middle of the screen.

4. Look at her for at least 30 seconds, but no more than 45 seconds.

5. Now look at your hand on the mouse.

6. No need to shout - your hand is okay.

Class: 8

Lesson presentation

Back forward

Attention! Slide previews are for informational purposes only and may not represent all the presentation options. If you are interested in this work, please download the full version.

Educational objectives of the lesson:

Formation of interest and cognitive motivation in teaching physics;
Development of theoretical thinking skills;
Creative search;
Formation of the concept of "illusion", types of illusions and identification of the causes of their occurrence;
Development of communication skills.

Main tasks:

Expansion and deepening of knowledge in physics.
Development of imaginative thinking.
Developing the ability to model and think creatively.
Development of communication skills and individual personality traits of students.
The development of students' emotions by creating a state of surprise, amusement, paradox during the lesson.

Equipment: computer; multi-video projector; presentation.

Lesson type: learning new material.

During the classes

The visible does not always correspond to the reality.
N. Copernicus

I. Organizational moment of the lesson

- Hello, dear guys! The epigraph of our lesson is the words "The visible does not always correspond to the reality", said by N. Copernicus. Today in the lesson we will try to understand some of the mysteries of nature. The topic of our lesson "Optical illusions"

- It is known that our vision is imperfect. Sometimes we observe not what is actually happening. But this is a fact. Let's try to understand the peculiarities of our observations.

II. Learning new material using the presentation.

Optical illusion concept. (slides 2-3)

What is an optical illusion? An optical illusion is called a representation of a visible phenomenon or object that does not correspond to reality due to the structural features of our visual apparatus, simply speaking, this is an incorrect representation of reality. Optical illusions are not associated with individual visual impairments, such as color blindness.

What causes optical illusion? The human visual apparatus is a complex system with a well-defined limit of functionality. It includes: the eyes, nerve cells through which the signal is transmitted from the eye to the brain, and the part of the brain responsible for visual perception. (picture 1).

Picture 1

In this regard, there are three reasons for the illusion:

Our eyes perceive the light coming from an object in such a way that erroneous information comes to the brain;
If the transmission of information signals along the nerves is disturbed, failures occur, which again leads to erroneous perception;
The brain does not always respond correctly to signals coming from the eyes. (picture 2)

Figure 2

About the reasons for visual illusions (errors, deceptions), one should, first, indicate that sometimes they appear as a result of specially created, special observation conditions, for example: observation with one eye, observation with motionless eye axes, observation through a slit, etc.

Secondly, most visual illusions do not arise from the optical perfection of the eye.

Illusions of sight do not include optical tricks and mysterious ghosts created with mirrors, projection devices and other technical devices, as well as interesting optical phenomena sometimes observed in nature (mirages, aurora borealis). The appearance of the latter is due to the optical properties of the earth's atmosphere.

Consider some types of illusions:

1. The illusion of depth perception . (slides 5, 6)

Visual illusions arise under the conditions of the relief we see or the depth of the picture. The emergence of these illusions is associated with the ability of the eye to see objects at different distances, with the ability to perceive space by the brightness of objects, by their shadows and by the number of intermediate objects. On the other hand, these illusions also arise in the process of comprehending the visible. The brain, perceiving an object, distorts the relief image we see. An example of this is the given figure: the cube seems to be seen from above, then from the side. (picture 3)

Figure 3

2. The illusion of size perception.(slides 7, 8)

We are generally accustomed to the fact that all objects receding to the horizon decrease on the retina in their linear dimensions: people, trains, clouds, airplanes ... (picture 4)

Figure 4

3. Illusion of movement perception. (slides 9-11)

I think this illusion is the most interesting because nothing really moves. If we make drawings of these pictures, the illusion still arises.

There is an illusion that can be called the Plateau spiral, or, more simply, the spinning top effect. If the disk with the spiral (top) is rotated clockwise, then after prolonged fixation with the eye we get the impression that all the branches of the spiral are pulling towards the center; when the spiral rotates in the opposite direction, we see the divergence of the spirals in the opposite direction from the center to the periphery. So, for example, if, after a long observation of the terrain from the window of a moving train or water from the window of a moving steamer, we turn our gaze to stationary objects inside the train or steamer, then it will seem to us that they are also moving, but in the opposite direction. These illusions are associated with successive moving images. (picture 5)

Figure 5

4. Impossible figures.(picture 6) (slides 12-13)

Figure 6

5. Upside down paintings (picture 7) (slide 14)

Figure 7

These are illusions associated with a change in orientation. Human visual mechanisms provide the ability to recognize objects viewed in different orientations, but a person gets used to certain observation conditions that prevail in everyday life. As a result of this habit, different orientations of objects become unequal for a person. This is especially true for human faces and printed text.

6. The ratio of figure and background.(Figure 8) (Slides 15-17)

Figure 8

Here we will consider a number of visual illusions caused by the influence of brightness contrast, i.e. the ratio of the difference between the brightness of the object and the background to the brightness of the background. Firstly, against a darker background, we see the figures as lighter and, conversely, against a lighter background, darker. Secondly, when perceiving a figure and a background, we tend to see, first of all, spots of a smaller area, as well as spots that are brighter "protruding", and more often the background seems to us to lie farther from us, behind the figure. The higher the brightness contrast, the better the object is visible and the more clearly its outline and shape are visible.

7. Dual images. (picture 9) (slide 18)

Figure 9

What do you see in the picture? Why does such an illusion arise? Consider carefully how many faces are there?

8. Goering's illusion.(Figure 10) (Slides 19-21)

Figure 10

Many illusions are explained by the ability of our eyes to exaggerate the sharp angles we see on flat figures. Perhaps this kind of illusion appears due to the phenomenon of irradiation, since the light space we see expands around the dark lines that limit the acute angle. The direction of movement of the eyes and their mobility in general are of great importance for these illusions. If there is a break in the lines, then our eye first of all "grasps" the acute angle, since the axis of the field of view first moves along the shortest direction and only then examines the sides of obtuse angles.

Sharp angles always appear larger than they really are, and therefore there are certain distortions in the true ratio of the parts of the visible figure. In the figure, parallel straight lines, due to the influence of the background, appear to be non-parallel and curved.

Sometimes the change in the direction of the lines and the distortion of the shape of the figure also occurs due to the fact that the eye follows the directions of other lines in the field of view. In this figure, the straight sides of the square appear to be curved, and the whole square appears to be deformed.

9. Apparent figures.(figure 11) (slides 22-23)

Figure 11

10. Recognition of images.(Figure 12) (Slides 24-26)

Figure 12

11. Tracking pictures.(picture 13) (slide 27)

Figure 13

Many have seen the so-called mysterious, as if alive, portraits that always look at us, following our movements and turning their eyes to where we go. This is because the pupils of the eyes in the portrait are placed in the middle of the eye section. This is how we see the eyes looking at us, when the eyes look to the side, past us, the pupil and the entire iris seem to us to be located not in the middle of the eye, but shifted to the side. When we move away from the portrait, the pupils, of course, do not change their position - they remain in the middle of the eyes, and since we continue to see the whole face in the same position in relation to us, it seems to us that the portrait has turned its head and is watching us

12. Colors and contrasts.(picture 14) (slide 28)

Figure 14

III. Conclusion.

If our eyes were not capable of succumbing to any deception, there would be no painting, architecture, sculpture, and we would be deprived of all the pleasures of the fine arts. We would not be able to understand optical illusions in the world around us and apply them in our lives.

Bibliography:

ME AND. Perelman. Entertaining physics. Book 2. - M .: Triada-Litera, 1994, p. 222-242.
Keith Kay. Optical illusions. Smolensk, "Rusich", 1999.

These are errors in visual perception caused by inaccuracy or inadequacy of the processes of unconscious correction of the visual image (incorrect assessment of the length of the segments, the size of the angles or the color of the depicted object, illusion of movement, "illusion of the absence of an object", banner blindness, etc.), as well as physical reasons (" flattened moon "," broken spoon "in a glass of water). The reasons for optical illusions are studied both when considering the physiology of vision and in the study of the psychology of visual perception. What are optical illusions?

The Ebbinghaus-Titchener Illusion (1902) The Illusion of Contrast. An illusion in which the same object is perceived as larger among small background objects and smaller among large background objects. To make sure that the circles are the same, of course, you can use a ruler, but you can also do without it. Close one eye and look at a conditional point in the middle between the circles. A few seconds later, you will see that they are the same.

This is a vertical-horizontal illusion. Both lines are the same length, but the vertical line appears to be longer than the horizontal one. This is a vertical-horizontal illusion. Both lines are the same length, but the vertical line appears to be longer than the horizontal one. The Wundt-Fick illusion or inverted T (1851)

Long parallel lines crossed by a series of short diagonal lines appear to diverge. Zölner noticed this illusion in 1860 by accident while examining the fabric. Long parallel lines crossed by a series of short diagonal lines appear to diverge. Zölner noticed this illusion in 1860 by accident while examining the fabric. Zöllner's Illusion (1860) Do these lines diverge? They are parallel

Look at the center of the left picture. Does it flicker and rotate? Now move your gaze to the center of the right picture, then again to the center of the left, etc. All the pictures presented here are absolutely static. Any movement seen is an illusion. ATTENTION! All pictures presented here are absolutely static. Any movement seen is an illusion.

Pictures taken from: Khalliulina Alina 8 "B" GOU CO 1428