Most of us are familiar with the phenomenon of optical illusions through entertainment sites, popular science books and the work of artists such as prints by the famous Maurits Escher. But optical illusions can not only surprise - they help scientists better understand how our sensory perception of the world around us relates to objective physical reality. The American organization Neural Correlate Society promotes such scientific research: every year it holds a competition where anyone can send an optical illusion they have discovered with an illustration and a small description. T&P chose five illusions - the winners of different years from the ones published on the competition website and described their effect.

The mechanisms responsible for the appearance of optical illusions are located in different parts of the human nervous system: from the retina of the eye to the visual area of ​​the cerebral cortex. The image that gets to the retina contains a huge amount of information, and not all of it is transmitted to the brain. Let the numbers speak for themselves: the retina contains, on average, 125 million photoreceptors and a hundred times fewer ganglion cells that generate nerve impulses. Our brains have to use abstract models to supplement and piece together the disparate pieces of incoming visual information. Sometimes he copes with this task too successfully: it forms a feeling of wholeness where it does not exist - in other words, it creates an optical illusion. Using several of them as an example, we will show how our brains deceive us.

Impossible movement illusion

The wooden balls in this video seem to roll up the incline as if being pulled by a magnet. Their behavior is inexplicable, as it contradicts the laws of physics. The image is not a computer 3D model, just the location of the grooves is perceived by the observer "in reverse" - in such a way that the descending movement of objects along them is taken as ascending. Notably, the illusion, created by Kokichi Sugihara of Japan's Meiji Institute for Advanced Study of Mathematical Sciences, uses material 3D objects and physical motion instead of a conventional 2D image. In this case, the deceptive effect is achieved by building a certain perspective: it is obvious that if we looked at this structure from any other angle, then the illusion would not work. The material model of the Penrose triangle or "impossible triangle", which was invented by young enthusiastic scientists, works according to the same laws. True, in order to be deceived, you will need to make an effort, because the illusion will work "correctly" only if you look at it from a certain point.

Rotating mask illusion

Whether we are looking at the curved or concave side of the mask, we cannot visually distinguish one from the other and will always perceive each of them as a face. As mentioned, everything we see is the result of electrical signals transmitted from the eye to the brain along the optic nerve. It is the brain that processes these signals and constructs a specific image that our consciousness can perceive. What's more, neuroscientists believe that there are certain areas in our brains that are responsible for recognizing faces. From our experience, we know that faces are convex, and the brain produces an image that matches our expectations and prevailing patterns. The habit is so strong that even the three-dimensional model of reality that is created by our stereoscopic vision is ignored. Interestingly, people suffering from schizophrenia cannot be fooled and are able to visually recognize the concave side of the mask. Raw visual information in their case is not "rewritten" by higher cognitive processes in the brain. Some psychologists believe that this dysfunction in signal processing (when sensory perception dominates consciousness) increases the patient's sense of dissociation from reality.

Falling tower illusion

Despite its apparent simplicity, the effect of this illusion was first described in 2007 by scientists at McGill University in Canada. The two images of the Leaning Tower of Pisa are identical, but the observer has a strong feeling that the slope of the right tower is greater, as if it were photographed from a different angle. The fact is that the adjacent photographs are perceived by us as one image. Usually, due to the laws of perspective, taken into account by our visual system, the contours of two adjacent towers tend to the same point as they move away from the field of view. But if their contours are parallel, our brain assumes that the towers should diverge in different directions. The main discovery of scientists was the fact that our visual system treats two identical images as a single landscape: no matter how we try to perceive them separately, we will always see the "Leaning Twin Towers", whose perspective can be explained only by the fact that the inclination of one there are many more of the towers.

Dynamic Ebbinghaus effect

The geometric Ebbinghaus illusion is possible due to our perception of the relationship between the sizes of objects. A person of average height will appear taller or shorter depending on whether he is standing next to a professional basketball player or a hobbit. Likewise, the center circle will appear larger or smaller depending on the size of the surrounding objects. This phenomenon can be explained as follows: our perception adjusts to a certain relationship between the object and its environment and extracts from it a certain criterion, which is then transferred to a new situation. For simplicity, this can be compared to the perception of sounds: if your laptop suddenly stops buzzing, you instantly become aware of the silence in the room, although before that you might not have paid attention to the noise it made. In the classical Ebbinghaus illusion, objects are static, but it turned out that the visual effect is significantly enhanced in dynamics: according to scientists at the University of Nevada, the authors of the illusion, the error in the perception of size almost doubles.

The multisensory "disappearing hand" illusion

This illusion, originally conceived by scientists at the University of Nottingham as a simulation of sensory loss in stroke survivors, uses vision, touch and a sense of body position. The participant in the experiment does not notice how his perception of the position of his own hands gradually changes: after special manipulations programmed by scientists, the hands are much farther from each other than it seems to the subject. When the right hand disappears from the screen, he reaches for it with his left hand, but all he finds is an empty table. The combination of loss of visibility and physical contact with your hand creates a complete illusion of its absence. Such experiments prove that perception errors can occur not only when viewing optical illusions - our entire apparatus for receiving and interpreting reality is strongly limited by abstract models developed by our brain in the process of evolution. We do not know how reality actually looks and sounds, we do not know exactly what it feels like, it is easy to mislead us, but it is thanks to scientific research that we will be able to get closer to the most complete perception of the world around us.

Learn more about illusions:

We bring to your attention 10 amazing magic tricks, experiments, or scientific shows that you can do yourself at home.
At a child's birthday, weekend or vacation, spend time with benefit and become the center of attention of many eyes! 🙂

An experienced organizer of scientific shows helped us in preparing the post - Professor Nicolas... He explained the principles that lie in one focus or another.

1 - Lava lamp

1. Surely many of you have seen a lamp that has a liquid inside that simulates hot lava. It looks magical.

2. Water is poured into sunflower oil and food coloring (red or blue) is added.

3. After that, add an effervescent aspirin to the vessel and observe an amazing effect.

4. In the course of the reaction, the colored water rises and falls through the oil without mixing with it. And if you turn off the light and turn on the flashlight, "real magic" begins.

: “Water and oil have different densities, moreover, they have the property of not mixing, no matter how we shake the bottle. When we add effervescent tablets inside the bottle, they dissolve in water, release carbon dioxide and set the liquid in motion. "

Want to put on a real science show? More experiences can be found in the book "The Experiments of Professor Nicolas".

2 - Soda experience

5. Surely at home or in a nearby store for the holiday there are several cans of soda. Before drinking them, ask the children a question: "What happens if you immerse cans of soda in water?"
Will they drown? Will they swim? Depends on the soda.
Invite the children to guess in advance what will happen to this or that jar and conduct the experiment.

4 - Soap volcano

How to make a small volcano erupt at home?

6 - Water in the sieve

We continue to study the magical properties of water and surrounding objects. Ask someone present to put on a bandage and pour water through it. As we can see, it easily passes through the holes in the bandage.
Argue with others that you can make sure that the water does not pass through the bandage without any additional tricks.

Commentary by Professor Nicolas: “Thanks to such a property of water as surface tension, water molecules want to be together all the time and it is not so easy to separate them (they are such wonderful girlfriends!). And if the size of the holes is small (as in our case), then the film does not break even under the weight of water! "

7 - Diving bell

And in order to secure for you the honorary title of Water Mage and Lord of the Elements, promise that you can deliver the paper to the bottom of any ocean (or bath or even a basin) without getting it wet.

26. We fold the sheet, put it in a glass so that it rests against its walls and does not slide down. We immerse the leaf in an inverted glass to the bottom of the tank.

27. The paper remains dry - water cannot reach it! After you take out the sheet - let the audience make sure that it is really dry.

Commentary by Professor Nicolas: “If you take a glass with a piece of paper inside and look closely at it, it seems that there is nothing but paper, but this is not so, there is air in it.
When we turn the glass upside down and put it in water, the air prevents the water from getting close to the paper, which is why it stays dry.

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Legendary stories, legendary tattoo choices made under duress, emotional storm, upset relationships, or under the influence of a substance ... But in the end, you yourself are responsible for your silly tattoos. Below is the second part of the photo gallery of prominent people who have such horrible tattoos that everyone will take pictures of and each for their own reasons. Well, I can think [...]

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From time to time, people appear on TV screens doing amazing things. In their hands, an ordinary wooden stick passes through thick glass, and multi-colored tennis balls appear out of nowhere and just as suddenly disappear. A deck of cards in skilled hands turns into an endless series of fascinating puzzles that you do not have time to solve - so quickly one trick is replaced by another. An attempt to unravel the secrets leaves no other way but to learn the tricks on your own. But remember that this fun activity is not as easy as it seems at first glance.

Magic tricks with cards

The spread of popularity is explained, first of all, by the availability of the requisites necessary for the display. It's easy to learn - you get a deck of cards and the fun begins.

Props: deck of cards.

External effect. One of the spectators shuffles the cards and makes sure that the deck contains no secrets. After dividing the deck of cards into 4 parts, have three viewers choose and remember one card from the three parts of the deck. Hold the fourth part in your hands. The deck is reassembled, and a random spectator deals cards one by one to 3 equal piles, according to the number of guessed cards. The number of cards to be dealt is randomly selected, but their number in each pile must be the same. The spectators' chosen cards are placed on top of each pile. Then the deck is connected. After inviting the audience to remove the deck several times, the magician makes a circular layout and names the cards chosen by the audience.

The secret of focus in the fourth pile, which remained in the hands of the performer during the selection of cards by 3 participants. Remember the first card from the part of the deck that remains in your hands. When assembling the deck, place the part with the card known to you on top. With further layout, it will appear at the bottom. Then, when folding the deck, after the audience has placed their cards on each pile, it will be located above the first of them. Dealing cards in a circle, expect yours to appear. The next card, and every fourth after it, will be the ones chosen by the audience.

Tricks with coins

Before you learn how to do magic tricks, identify the audience you are going to surprise. For home shows, tricks using familiar objects are suitable.

Props: coin and matchbox.

External effect. Show an empty matchbox, open it, close it, shake it confirming that it is empty. Reopen and carefully remove the metal coin from the inner compartment. Pass the coin and boxes to the audience for inspection.

The secret of focus consists in the fact that the coin is hiding in advance between the moving part and the top cover. While pulling out the inner part for inspection, discreetly hold a coin with your finger and press the box against the upper stationary part. When closing the box, release the coin and it will fall inside. After that, open the box and demonstrate the appearance of a metal coin that appeared there.

Table tricks

It is not difficult to create a simple illusion, you just need to know how. The simplest tricks help to learn tricks, by the example of which a novice magician comprehends the basics of working with improvised props.

Props: a bowl of water and talcum powder.

External effect. The illusionist pours tap water into a bowl of water. Ask someone from the audience to do this procedure - this way the public will have no doubt that the water and the bowl do not contain secrets. Ask the audience if you can submerge your hand in the liquid and not get it wet. The answer is obvious, and anyone can try it. But the magician puts his hand into the water, and it remains completely dry.

The secret of the trick consists of a colorless talcum powder, which is applied to the hand. Not a single drop of water lingers on the magician's hand immersed in liquid. One gets the impression that the illusionist in the literal sense of the word managed to get out of the water dry. Instead of talcum powder, try stearic zinc if desired. It has enhanced water-repellent properties.

Tricks with ropes

After you have managed to overcome the first steps in the art of illusion and learn how to make a special props yourself.

Props: rope with a secret.

External effect. The magician demonstrates a thick rope to the audience and wonders if it can be made to take an upright position. For the experiment, a spectator is invited, who checks the rope and tries to complete the task. Then the magician gets down to business. He ties a knot at one end and stretches the rope vertically. Releases the upper edge (with a knot), and the cord remains firmly on the arm in an upright position. A light blow to the center of the rope - it falls and becomes soft again.

The secret of focus is in a specially prepared rope. From any thick cord, internal synthetic threads are removed, which serve as a filler. The vacant space is filled with wooden cylinders, dressed with strong thread or fishing line. The cylinders are sized to match the inside diameter of the rope. The length is 25-30 mm. For a thin curtain cord, cylinders made from a round pencil with a pre-removed lead are suitable. The number of cylinders depends on the length of the rope they fill. On one side, the fishing line with the cylinders is fixed to the edge of the rope, and on the other, a circle is attached to it, which protects the cylinders from slipping. The length of the line and cylinders is slightly less than the length of the rope. Due to this, in a loose state, the cord retains its softness and elasticity.

By tying a knot on the side with the attached line, the illusionist with the other hand, through the soft braid of the cord, forces the cylinders inside the rope to slide close to each other. On this basis, the outer sheath of the rope will assume a rigid vertical position. Striking the cord and relaxing the fingers, the magician releases the inner cylinders, and the rope falls freely.

Tricks with scarves

Learning tricks at home is not a problem - the repertoire of an amateur magician includes tricks that do not require large boxes or complex mechanisms.

Props: handkerchief and matches.

External effect. The sorcerer shows off a handkerchief. Viewers can see that it is empty and does not contain any secrets. The handkerchief is spread out on the table and a match is placed in the center, which is preliminarily examined by the public. The magician folds the handkerchief in such a way as to hide the match. Then he hands over the rolled weave to the viewer, asks to feel for a match and break it in several places. He takes the handkerchief, puts it on the table and unfolds it. In the center, viewers see a match that has remained intact.

The secret of focus consists in the second match, previously placed in the side seam of the scarf. When demonstrating the props, the magician holds the fabric at the corner where the second match is hidden. Folding the shawl and hiding a real match, the illusionist places the corner of the shawl in the middle of the fabric where the "tab" is. It is her viewer who probes through the fabric and breaks. Naturally, when the scarf is unfolded, a whole and undamaged match is found in it.

Complex magic tricks using special props

For the first illusion session, you will have to make simple devices that will help you show fascinating tricks. A novice performer will not only have to learn how to learn tricks - get ready to become a designer of some of them.

Props. with a secret, notepad, pencil.

External effect. The performer demonstrates a small black board in a wooden frame and says that this magic board can count. After that, he wraps it in a newspaper, seals it with tape and transfers it to the viewer for storage. Then he takes a notebook and a pencil and asks 4 spectators to write in a column, one five-digit number each. Tears out a sheet of numbers from a notebook and invites another viewer to calculate and write down the sum of the numbers at the bottom. Tears off half of the sheet with the result and leaves it with the audience. He cuts the tape along with the newspaper and demonstrates the blackboard on which a number written in chalk appears. The spectators check the answer - the amount on the piece of paper and on the board is the same.

The secret of focus is covered in two details.

1. The slate board consists of two parts. The board itself is in the frame and the liner, which fits to the inner size of the frame and covers the main part of the board. The outer part of the liner and the board are painted the same black. The second side of the insert is painted to match the tablecloth on which the magician places the props.
2. The notebook should have an unprinted cover and be easy to open from either side.

On the first page of the notebook, the magician writes 4 numbers in advance, calculates their sum and writes them down with chalk on a slate board. From above, the answer is closed by an insert and externally the board looks clean. Having shown the board to the audience, the magician turns it away from the audience, puts it on the table and wraps it in newspaper. At this moment, he drops the insert on the table and wraps the board without showing the audience the front side with the written number. For reliability, the newspaper is secured with tape, and the props are handed over to the audience.

The magician asks 4 different spectators to write down the numbers in a column on the blank side of the notebook. Passing to the fifth viewer to calculate the amount, he turns the notebook over, tears out a sheet with pre-written numbers, the amount of which is offered to the viewer to calculate. To prevent the deception from being revealed, the performer tears off part of the sheet with the amount and leaves it with the viewer. The other half, with the numbers prepared in advance, he puts in his pocket. After that, he takes the board away from the audience, removes the scotch tape with the newspaper and demonstrates the number written on the board in advance. Naturally, it coincides with the amount calculated by the viewer.

Applause! Astonishment! Mistrust! Delight! And endless questions about how to learn tricks at home are guaranteed to accompany a novice illusionist after such a spectacular final trick.

It is important not only to understand how to learn magic tricks. Follow the rules that will help you build your program and present your prepared tricks to the audience.

1. Rehearse each trick carefully in front of a mirror. Achieve accurate gestures, confident work with props, prepare for possible surprises that lie in wait for you when performing in front of an audience.
2. Don't tell in advance what you are going to do. Knowing in advance what task you have set for yourself, the audience will closely follow you, and it will be difficult to distract their attention at the right time.
3. Don't do the same trick twice in the same talk. On re-viewing, viewers who are aware of the end result of the focus will definitely try to reveal your secret.
4. Do not fall for persuasion and do not reveal the secrets of the tricks you demonstrate. A trick, the secret of which has been exposed, ceases to be amazing and mysterious, loses the aura of incomprehensible magic.