Therefore, when you look at an object for a long time and suddenly look away, this phenomenon will occur. People's eyes consume some substances to see things, and brighter light consumes more, just like pressing hard on the skin, where the pressure is high, it will be whiter.
The formation of vision needs a complete vision analyzer, including eyeball and occipital lobe of cerebral cortex, and the visual pathway system between them. Due to the characteristics of light, human eyes will have quite complex reactions to the stimulation of light, and light has many functions. When people look at things, the image of the object passes through the pupil and lens and falls on the retina. Stimulated by light, the optic nerve cells in the retina convert light signals into bioelectric signals, which are transmitted to the brain through the nervous system, and then form vision according to extremely complicated processes such as human experience, memory, analysis, judgment and recognition, and form concepts such as the shape and color of objects in the brain.
Human eyes can not only distinguish the shape, brightness and color of objects, but also produce more visual functions (eye muscle activity, etc.) with the cooperation of visual analyzer and motion analyzer. ). At the same time, each function influences and complements each other in time and space, making the vision more exquisite and perfect. Therefore, vision is a multifunctional name, and what we often say is only one of its contents. The generalized visual function should be composed of four successive stages: visual perception, quantum absorption, specific space-time composition and the consistency of psychology and nerves.
Illusion refers to people's incorrect feelings or perceptions of external things. The most common is optical illusion. The reasons for illusion are not only the influence of the characteristics of objective stimulus itself, but also the physiological and psychological reasons of observers. Its mechanism is not fully understood. Physiological reasons are related to the structure and characteristics of our sensory organs; Psychological reasons are related to our living conditions and experiences. In real life, people often perceive and adapt to the objective world in the process of constantly correcting mistakes. The ability to distinguish the characteristics of external stimuli (information) is an important means for us to know the world and acquire knowledge. At the same time, we should constantly correct wrong reflections. This is very important in life, work and study. For example, people who have lost their hearing will become difficult to understand over time, because they can't hear their own voice (language), can't get feedback and correction, and even lead to the loss of language. Therefore, constantly correcting the wrong feedback of the senses can improve our understanding level. External things are diverse and ever-changing, and the relationship between them is complicated. However, people's reflection on external things in their minds only holds external things conditionally and approximately, and their understanding of things has personal limitations. But dialectical materialism holds that objective things are knowable and people's understanding of the objective world is endless. As far as illusion (perception of objective things) is concerned, there are many illusions caused by phenomena based on our physiological basis, except "a cup of bow and a snake shadow", "grass is full of soldiers" and "the wind shakes the flower shadow, and it is suspected that a jade man is coming". For example, in our vision, when the image of an object falls on the blind spot of the retina, we will have the illusion of "turning a blind eye". (See the picture above) For another example, when watching a movie, the movements of the characters on the screen are jumping, and the images (pictures) are alternately bright and dark, but in our view, the movements of the characters are continuous, with no changes in light and dark. This takes advantage of the visual retention of the eyes. Movie pictures change at a speed of 24 frames per second, so that "jumping" pictures are regarded as continuous actions (the discontinuity of actions is imperceptible), and at the same time, because the eyes can keep the light effect acting on them for a certain period of time, people see not a series of flashing pictures, but stable pictures.
Therefore, it is necessary to use tools to prove it, so that it can be more accurate and powerful. What does this remind you of? The picture is like this, and the title is and should be like this. We should prove it with facts. When doing geometric proof, some reasons can't be made up. We should proceed from the facts and follow the meaning of the question.
In fact, the proof of mathematics is not difficult, the key is confidence and method.
(1) You must master the most basic proof methods and common methods, such as the proof and writing of triangle congruence, the proof and application of Pythagorean theorem, and the application of equations and functions in geometric problems.
(2) Be good at making auxiliary lines and master common auxiliary lines, such as height and vertical line. Of course, the more auxiliary lines, the better, generally no more than two (the geometry problem that must be done with two auxiliary lines is a difficult problem). In addition, we must know when and what kind of auxiliary lines to make. Generally, we will make the height for the area, and we often connect the radius in the circle and so on.
(3) Algebra (arithmetic and equation function) can be used to solve some geometric proof problems.
(4) Be good at finding the connection between the known conditions and the unknown conditions in the topic and adopt flexible and effective methods to solve it. If the two line segments to be proved appear in two triangles, then you should study whether the relationship between the two triangles is congruent or similar, and how to prove congruence or similarity.
(5) We should constantly summarize the exercises of various geometric problems, such as the introduction of several auxiliary lines (***7 kinds) of trapezoid, and how to solve problems in general circles.
So seeing is not necessarily believing, and all the reasons should be based on the meaning of the question.