This article talks about what energy quantization is and what significance this phenomenon has for modern science. The history of the discovery of the discreteness of energy is given, as well as the areas of application of the quantization of atoms.
End of Physics
At the end of the nineteenth century, scientists faced a dilemma: at the then level of technology development, all possible laws of physics were discovered, described and studied. Pupils who had highly developed abilities in the field of natural sciences were not advised by teachers to choose physics. They believed that it was no longer possible to become famous in it, there was only routine work to study small minor details. This was more suited to an attentive person, rather than a gifted one. However, the photo, which was more of an entertaining discovery, gave reason to think. It all started with simple inconsistencies. For starters, it turned out that the light was not entirely continuous: under certain conditions, burning hydrogen left a series of lines on the photographic plate instead of a single spot. Further it turned out that the spectra of helium hadmore lines than the spectra of hydrogen. Then it was found that the trail of some stars is different from others. And pure curiosity forced the researchers to manually put one experience after another in search of answers to questions. They did not think about the commercial application of their discoveries.
Planck and quantum
Fortunately for us, this breakthrough in physics was accompanied by the development of mathematics. Because the explanation of what was happening fit into incredibly complex formulas. In 1900, Max Planck, working on the theory of black body radiation, found out that energy is quantized. Briefly describe the meaning of this statement is quite simple. Any elementary particle can only be in some specific states. If we give a rough model, then the counter of such states can show the numbers 1, 3, 8, 13, 29, 138. And all other values between them are inaccessible. We will reveal the reasons for this a little later. However, if you delve into the history of this discovery, it is worth noting that the scientist himself, until the end of his life, considered energy quantization to be only a convenient mathematical trick, not endowed with serious physical meaning.
Wave and Mass
The beginning of the twentieth century was full of discoveries related to the world of elementary particles. But the big mystery was the following paradox: in some cases, the particles behaved like objects with mass (and, accordingly, momentum), and in some cases, like a wave. After long and stubborn debate, I had to come to an incredible conclusion: electrons, protons andneutrons have these properties at the same time. This phenomenon was called corpuscular-wave dualism (in the speech of Russian scientists two hundred years ago, a particle was called a corpuscle). Thus, an electron is a certain mass, as if smeared into a wave of a certain frequency. An electron that revolves around the nucleus of an atom endlessly superimposes its waves on top of each other. Consequently, only at certain distances from the center (which depend on the wavelength) the electron waves, rotating, do not cancel each other out. This happens when, when the "head" of a wave electron is superimposed on its "tail", the maxima coincide with the maxima, and the minima coincide with the minima. This explains the quantization of the energy of an atom, that is, the presence of strictly defined orbits in it, on which an electron can exist.
Spherical nanohorse in vacuum
However, real systems are incredibly complex. Obeying the logic described above, one can still understand the system of orbits of electrons in hydrogen and helium. However, further complex calculations are already required. To learn how to understand them, modern students study the quantization of particle energy in a potential well. To begin with, an ideally shaped well and a single model electron are chosen. For them, they solve the Schrödinger equation, find the energy levels at which the electron can be. After that, they learn to look for dependencies by introducing more and more variables: the width and depth of the well, the energy and frequency of the electron lose their certainty, adding complexity to the equations. Furtherthe shape of the pit changes (for example, it becomes square or jagged in profile, its edges lose their symmetry), hypothetical elementary particles with specified characteristics are taken. And only then do they learn to solve problems that involve quantization of the radiation energy of real atoms and even more complex systems.
Momentum, angular momentum
However, the energy level of, say, an electron is a more or less understandable value. One way or another, everyone imagines that the higher energy of the central heating batteries corresponds to a higher temperature in the apartment. Accordingly, the quantization of energy can still be imagined speculatively. There are also concepts in physics that are difficult to comprehend intuitively. In the macrocosm, momentum is the product of velocity and mass (don't forget that velocity, like momentum, is a vector quantity, that is, it depends on direction). It is thanks to the momentum that it is clear that a slowly flying medium-sized stone will only leave a bruise if it hits a person, while a small bullet fired at great speed will pierce the body through and through. In the microcosm, momentum is such a quantity that characterizes the connection of a particle with the surrounding space, as well as its ability to move and interact with other particles. The latter directly depends on the energy. Thus, it becomes clear that the quantization of energy and momentum of a particle must be interconnected. Moreover, the constant h, which denotes the smallest possible portion of a physical phenomenon and shows the discreteness of quantities, is included in the formula andenergy and momentum of particles in the nanoworld. But there is a concept even more distant from intuitive awareness - the moment of impulse. It refers to rotating bodies and indicates what mass and with what angular velocity rotates. Recall that the angular velocity indicates the amount of rotation per unit time. The angular momentum is also able to tell the way the substance of a rotating body is distributed: objects with the same mass, but concentrated near the axis of rotation or on the periphery, will have a different angular momentum. As the reader probably already guesses, in the world of the atom, the energy of the angular momentum is quantized.
Quantum and laser
The influence of the discovery of the discreteness of energy and other quantities is obvious. A detailed study of the world is possible only thanks to the quantum. Modern methods of studying matter, the use of various materials, and even the science of their creation are a natural continuation of understanding what energy quantization is. The principle of operation and the use of a laser is no exception. In general, the laser consists of three main elements: the working fluid, pumping and reflecting mirror. The working fluid is chosen in such a way that two relatively close levels for electrons exist in it. The most important criterion for these levels is the lifetime of electrons on them. That is, how long an electron is able to hold out in a certain state before moving to a lower and more stable position. Of the two levels, the upper one should be the longer lived. Then pumping (often with a conventional lamp, sometimes with an infrared lamp) gives the electronsenough energy for them all to gather at the top level of energy and accumulate there. This is called inverse level population. Further, some one electron passes into a lower and more stable state with the emission of a photon, which causes a breakdown of all electrons downward. The peculiarity of this process is that all the resulting photons have the same wavelength and are coherent. However, the working body, as a rule, is quite large, and flows are generated in it, directed in different directions. The role of the reflecting mirror is to filter out only those photon streams that are directed in one direction. As a result, the output is a narrow intense beam of coherent waves of the same wavelength. At first, this was considered possible only in a solid state. The first laser had an artificial ruby as a working medium. Now there are lasers of all kinds and types - on liquids, gases, and even on chemical reactions. As the reader sees, the main role in this process is played by the absorption and emission of light by the atom. In this case, energy quantization is only the basis for describing the theory.
Light and electron
Recall that the transition of an electron in an atom from one orbit to another is accompanied by either emission or absorption of energy. This energy appears in the form of a quantum of light or a photon. Formally, a photon is a particle, but it differs from other inhabitants of the nanoworld. A photon has no mass, but it does have momentum. This was proved by the Russian scientist Lebedev in 1899, clearly demonstrating the pressure of light. A photon exists only in motion and its speedequal to the speed of light. It is the fastest possible object in our universe. The speed of light (standardly denoted by the small Latin “c”) is about three hundred thousand kilometers per second. For example, the size of our galaxy (not the largest in space terms) is about one hundred thousand light years. Colliding with matter, the photon gives it its energy completely, as if dissolving in this case. The energy of a photon, which is released or absorbed when an electron moves from one orbit to another, depends on the distance between the orbits. If it is small, infrared radiation with low energy is emitted, if it is large, ultraviolet is obtained.
X-ray and gamma radiation
The electromagnetic scale after ultraviolet contains X-ray and gamma radiation. In general, they overlap in wavelength, frequency and energy in a fairly wide range. That is, there is an X-ray photon with a wavelength of 5 picometers and a gamma photon with the same wavelength. They differ only in the way they are received. X-rays occur in the presence of very fast electrons, and gamma radiation is obtained only in the processes of decay and fusion of atomic nuclei. X-ray is divided into soft (using it to show through the lungs and bones of a person) and hard (usually needed only for industrial or research purposes). If you accelerate the electron very strongly, and then decelerate it sharply (for example, by directing it into a solid body), then it will emit X-ray photons. When such electrons collide with matter, the target atoms break outelectrons from lower shells. In this case, the electrons of the upper shells take their place, also emitting X-rays during the transition.
Gamma quanta occur in other cases. The nuclei of atoms, although they consist of many elementary particles, are also small in size, which means that they are characterized by energy quantization. The transition of nuclei from an excited state to a lower state is precisely accompanied by the emission of gamma rays. Any reaction of decay or fusion of nuclei proceeds, including with the appearance of gamma photons.
Nuclear reaction
A little higher we mentioned that atomic nuclei also obey the laws of the quantum world. But there are substances in nature with such large nuclei that they become unstable. They tend to break down into smaller and more stable components. These, as the reader probably already guesses, include, for example, plutonium and uranium. When our planet formed from a protoplanetary disk, it had a certain amount of radioactive substances in it. Over time, they decayed, turning into other chemical elements. But still, a certain amount of undecayed uranium has survived to this day, and by its amount one can judge, for example, the age of the Earth. For chemical elements that have natural radioactivity, there is such a characteristic as half-life. This is the period of time during which the number of remaining atoms of this type will be halved. The half-life of plutonium, for example, occurs in twenty-four thousand years. However, in addition to natural radioactivity, there is also forced. When bombarded with heavy alpha particles or light neutrons, the nuclei of atoms break apart. In this case, three types of ionizing radiation are distinguished: alpha particles, beta particles, gamma rays. Beta decay causes the nuclear charge to change by one. Alpha particles take two positrons from the nucleus. Gamma radiation has no charge and is not deflected by an electromagnetic field, but it has the highest penetrating power. Energy quantization occurs in all cases of nuclear decay.
War and Peace
Lasers, x-rays, the study of solids and stars - all these are peaceful applications of knowledge about quanta. However, our world is full of threats, and everyone seeks to protect themselves. Science serves military purposes too. Even such a purely theoretical phenomenon as the quantization of energy has been put on guard of the world. The definition of the discreteness of any radiation, for example, formed the basis of nuclear weapons. Of course, there are only a few of its combat applications - the reader probably remembers Hiroshima and Nagasaki. All other reasons to press the coveted red button were more or less peaceful. Also, there is always the question of radioactive contamination of the environment. For example, the half-life of plutonium, indicated above, makes the landscape in which this element enters unusable for a very long time, almost a geological epoch.
Water and wires
Let's get back to the peaceful use of nuclear reactions. We are talking, of course, about the generation of electricity by nuclear fission. The process looks like this:
In the coreIn the reactor, free neutrons first appear, and then they hit a radioactive element (usually an isotope of uranium), which undergoes alpha or beta decay.
To prevent this reaction from going into an uncontrolled stage, the reactor core contains so-called moderators. As a rule, these are graphite rods, which absorb neutrons very well. By adjusting their length, you can monitor the reaction rate.
As a result, one element turns into another, and an incredible amount of energy is released. This energy is absorbed by a container filled with so-called heavy water (instead of hydrogen in deuterium molecules). As a result of contact with the reactor core, this water is heavily contaminated with radioactive decay products. It is the disposal of this water that is the biggest problem of nuclear energy at the moment.
The second is placed in the first water circuit, the third is placed in the second. The water of the third circuit is already safe to use, and it is she who turns the turbine, which generates electricity.
Despite such a large number of intermediaries between the directly generating cores and the end consumer (let's not forget the tens of kilometers of wires that also lose power), this reaction provides incredible power. For example, one nuclear power plant can supply electricity to an entire area with many industries.
