Most likely, today there is not a single house where there is no mirror. It has so firmly entered our lives that it is difficult for a person to do without it. What is this object, how does the image reflect? And if you put two mirrors opposite each other? This amazing item has become central to many tales. About him there are enough signs. And what does science say about the mirror?
A bit of history
Most modern mirrors are coated glass. As a coating, a thin metal layer is applied to the back of the glass. Just a thousand years ago, mirrors were carefully polished copper or bronze discs. But not everyone could afford a mirror. It cost a lot of money. Therefore, poor people were forced to consider their reflection in the water. And mirrors that show a person to their full height are generally a relatively young invention. He is about 400 years old.
The mirror of people surprised even more so when they could see the reflection of the mirror in the mirror - it generally seemed to them something magical. After all, the image is not the truth, but a certain reflection of it, a kind of illusion. It turns out that we can simultaneously see truth and illusion. It is not surprising that people attributed this item many magical properties and were even afraid of it.
The very first mirrors were made of platinum (surprisingly, but once this metal was not appreciated at all), gold or tin. Scientists have discovered mirrors made back in the Bronze Age. But the mirror that we can see today began its history after Europe was able to master the technology of glass blowing.
Scientific view
From the point of view of the science of physics, the reflection of a mirror in a mirror is a multiplied effect of the same reflection. The more such mirrors are installed opposite each other, the greater the illusion of fullness with the same image arises. This effect is often used in attractions for entertainment. For example, there is a so-called endless hall in the Disney park. There, two mirrors were set opposite each other, and repeated this effect many times.
The resulting reflection of the mirror in the mirror, multiplied by a relatively infinite number of times, has become one of the most popular among attractions. Such attractions have long entered the entertainment industry. At the beginning of the 20th century, an attraction called the “Palace of Illusions” appeared at an international exhibition in Paris. He was very popular. The principle of its creation is the reflection of mirrors in mirrors mounted in a row, the size of a full human height, in a huge pavilion. People seemed to be in a huge crowd.
Law of reflection
The principle of operation of any mirror is based on the law of propagation and reflection in space of light rays. This law is the main one in optics: the angle of incidence will be the same (equal) to the angle of reflection. It is like a falling ball. If it is thrown vertically down towards the floor, it will also bounce vertically up. If you throw it at an angle, it will bounce at an angle equal to the angle of incidence. Rays of light from the surface are reflected similarly. Moreover, the smoother and smoother this surface, the more ideal this law works. According to this law, reflection in a flat mirror works, and the more perfect its surface, the better the reflection.
But if we are dealing with matte surfaces or with rough ones, then the rays are scattered randomly.
Mirrors can reflect light. What we see, all reflected objects, is due to rays that are similar to the sun. If there is no light, then nothing is visible in the mirror. When light rays fall on an object or any living creature, they are reflected and carry information about the object with them. Thus, the reflection of a person in a mirror is a representation of an object formed on the retina of his eye and transmitted to the brain with all its characteristics (color, size, distance, etc.).
Types of mirror surfaces
Mirrors are flat and spherical, which, in turn, can be concave and convex. Today there are already smart mirrors: a kind of media, designed to demonstrate the target audience. The principle of its work is as follows: when a person approaches, the mirror seems to come to life and starts showing the video. Moreover, this video was not chosen by chance. A system is mounted in the mirror that recognizes and processes the resulting image of a person. She quickly determines his gender, age, emotional mood. Thus, the system in the mirror selects a demo clip that is potentially able to interest a person. It works in 85 cases out of 100! But scientists do not stop there and want to achieve accuracy of 98%.
Spherical Mirror Surfaces
What is the basis of the work of a spherical mirror, or, as they call it, a curve, - mirrors with convex and concave surfaces? Such mirrors differ from ordinary ones in that they distort the image. Convex mirror surfaces make it possible to see more objects than flat ones. But at the same time, all these objects seem smaller in size. Such mirrors are installed in cars. Then the driver has the opportunity to see the image on the left and on the right.
A concave curved mirror focuses the resulting image. In this case, you can see the reflected object as detailed as possible. A simple example: these mirrors are often used in shaving and in medicine. The image of an object in such mirrors is collected from images of many different and separate points of this object. To build an image of an object in a concave mirror, it will be enough to build an image of its extreme two points. Images of the remaining points will be located between them.
Translucency
There is another type of mirror with translucent surfaces. They are so arranged that one side is like an ordinary mirror, and the other is half transparent. From this transparent side, you can observe the view behind the mirror, but from the ordinary you can see nothing but reflection. Such mirrors can often be seen in crime films when police officers investigate and interrogate a suspect, and on the other hand they watch him or bring witnesses to identify them, but so that they are not visible.
The myth of infinity
It is believed that by creating a mirror corridor, you can achieve the infinity of the light beam in the mirrors. Superstitious people who believe in fortune telling often use this ritual. But science has long proved that this is impossible. Interestingly, the reflection of light from a mirror is never complete, 100%. This requires a perfect, 100% smooth surface. And it can be such by approximately 98-99%. Any errors always take place. Therefore, girls, fortunetellers in such mirrored corridors by candlelight, risk, at most, simply to enter a certain psychological state that can negatively affect them.
If you put two mirrors opposite each other, and light a candle between them, you will see many lights in a row. Question: how many lights can be counted? At first glance, this is an infinite amount. Indeed, there seems to be no end to this series. But if we carry out certain mathematical calculations, we will see that even with mirrors having 99% reflection, after about 70 cycles, the light will become half as weak. After 140 reflections, it will weaken twice more. Each time, the rays of light fade and change color. Thus, there will come a moment when the light goes out altogether.
So is infinity possible?
Infinite reflection of the beam from the mirror is possible only with absolutely perfect mirrors set strictly parallel. But is it possible to achieve such absoluteness when nothing in the material world is absolute and ideal? If this is possible, it is only from the point of view of religious consciousness, where absolute perfection is God, the Creator of everything omnipresent.
Due to the lack of an ideal mirror surface and perfect parallelism between them, a number of reflections will undergo bending and the image will disappear, as if around a corner. If we also take into account the fact that a person looking at this reflection, when there are two mirrors, and he is also a candle between them, also does not stand strictly parallel, then the visible row of candles will disappear outside the mirror frame quite quickly.
Multiple reflection
At school, students learn to construct images of an object using the laws of reflection. According to the law of reflection of light in a mirror, an object and its mirror image are symmetrical. Studying the construction of images using a system of two or more mirrors, students receive the effect of multiple reflection.
If we add to the single flat mirror the second one located at right angles to the first one, then not two reflections will appear in the mirror, but three (usually denoted by S1, S2 and S3). The rule works: the image that appears in one mirror is reflected in the second, then this first is reflected in the other, and again. The new, S2, will be reflected in the first, creating a third image. All reflections will match.
Symmetry
The question arises: why are the reflections in the mirror symmetrical? The answer is given by geometric science, and in close connection with psychology. What is bottom and top for us is reversed for the mirror. The mirror, as it were, turns inside out what is in front of it. But it is surprising that in the end the floor, walls, ceiling and everything else in the reflection looks the same as in reality.
How does a person perceive a reflection in a mirror?
Man sees through light. Its quanta (photons) have the properties of waves and particles. Based on the theory of primary and secondary sources of light, photons of a ray of light falling on an opaque object are absorbed by atoms on its surface. Excited atoms immediately return the energy that they have absorbed. Secondary photons are emitted uniformly in all directions. Rough and matte surfaces give a diffuse reflection.
If this is a mirror surface (or similar), then the light emitting particles are ordered, the light exhibits wave characteristics. Secondary waves are compensated in all directions, in addition to obeying the law that the angle of incidence is equal to the angle of reflection.
Photons, as it were, elastically jumps from the mirror. Their trajectories begin from objects, as if located behind him. It is them that the human eye sees when looking in the mirror. The world behind the mirror is different from the real one. To read the text there, you need to start from right to left, and the clock hands go in the opposite direction. The double in the mirror raises his left hand, when the person standing in front of the mirror - his right.
The reflections in the mirror will be different for people who are simultaneously looking into it, but at different distances and in different positions.
The best mirrors in antiquity were considered to be those made of carefully polished silver. Today, a metal layer is applied on the back of the glass. It is protected from damage by several layers of paint. Instead of silver, to save money, an aluminum layer is often applied (reflection coefficient approximately 90%). A person’s eyes hardly notice the difference between a silver coating and an aluminum one.