What are physicists thinking about?

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“That night, despondency reigned in the laboratory. In an attempt to obtain and identify elements 101 - the next link in the chain of artificial human preparation of chemical elements beyond uranium - we carried out many careful experiments, but they all ended in failure. Now we were finishing our last experiment, the origins of which seemed, however, unconvincing. A tiny sample of our materials preparation, even at best, could contain only one or two atoms of the elusive element 101…

We closely monitored the recording of impulses associated with the use of the camera. An hour has passed. The time was approaching dawn. The wait seemed endless. Finally this case! The pen of the beeping mechanism jumped to the middle of the scale and fell down, leaving a clear red line: it was a large initialization pulse… About an hour later, a second pulse, similar to the first, was recorded. We were now confident that we were witnessing the disintegration of two atoms of element 101 and thus had added a new element to the chemical family.**

Thus begins the story of American physicists Glenn Seaborg and Albert Ghiorzo about the creation of new chemical elements. In Russian translation, it is included in the first issue of the collection “What Physicists Are Thinking About,” which was published in 1962. Since then, this series of popular science collections has been replenished with five more issues. The first two of them were published by the State Publishing House of Physics and Mathematics Literature, the rest by the Nauka Publishing House. Here are the titles of these releases:

Issue 1. Physics of the atomic nucleus (1962, price 23 kopecks).
Issue 2. Elementary particles (1963, price 25 kopecks).
Issue 3. Elementary particles (1965, price 43 kopecks).
Issue 4. Physics of the atomic nucleus (1965, price 29 kopecks).
Issue 5. Quantum macrophysics (1967, price 62 kopecks).
Issue 6. Astrophysics (1967, price 1 rub. 06 kopecks).
All these books are from the very cutting edge of science. That’s why they are called “What Physicists Think About.” Indeed, they talk about what scientists are doing these days, and sometimes about what they are still planning to do. It’s not for nothing that the article will end in much the same way as Robert Marshak’s “Nuclear Forces”, published in four issues:

“What can be said about the cherished dream of physicists - a true theoretical understanding of nuclear forces? All we can do at the moment is to express the hope that we are on the right track… However, we are confident that someday we will be able to write the right issue."

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equations and find a way to solve them. Until then, we seem to have no choice but to press ahead using the empirical approximations described in this paper.”
Nowadays, science is developing incredibly quickly, and textbooks, naturally, cannot keep up with this development. If you get acquainted with some modern science only from a textbook, then it may seem that everything has already been done in it, all the problems have been solved, the mine, so to speak, has already been worked out, the ore has been finished off and only waste rock is left to your share. It even becomes a bit of a shame that I was born late. All countries have already been discovered and there are no blank spots on the map of the Earth, all the laws have been found - Newton, Coulomb, Ampere, Joule - Lenz, etc., the theory of relative mechanics and quantum mechanics have been created. It would seem, what else? But in reality this is not the case, and physics today faces many unsolved problems.

What substance does elementary particles consist of (electrons, neutrons, protons, etc.) and what is their structure? Perhaps they are homogeneous components of unknown matter, or perhaps, as the famous Russian poet Valery Bryusov once wrote,

“these electrons are Worlds where there are five continents, Arts, knowledge, wars, thrones and the memory of forty centuries!”

What is the nature of gravitational forces, and how do they arise? What are nuclear forces? Where does the periodic system of elements end and what other atoms can be added to it? Is there somewhere in the bottomless depths of space at least one anti-world, built from anti-morality? How many elementary particles does nature have and what are their properties?

Such problems are discussed in the collection “What Physicists Are Thinking About.” Moreover, as a rule, it is told first-hand by major scientists who themselves conduct these studies. Therefore, reading the article, as if entering their laboratory, you learn many interesting details and begin to better understand how science is done.

Despite the fact that in these collections the conversation is always about the latest problems in physics, which are generally very difficult to understand, they invariably remain completely accessible to high school students. The authors with great skill use the entire arsenal of truly scientific means: they provide simple examples and analyses, use clear models of various physical processes, and practically do without complex mathematical apparatus. The stats are written in a very interesting, lively, figurative language and sometimes read like works of art, although they have a global physical meaning.

Here is a brief description of the main content of these collections.

Two issues (the first and fourth) talk about the research of atomic nuclei. First of all, it will decide about research tools - accelerating charged particles, sophisticated cameras, special highly sensitive photographic plastics, spectrometers. Other articles examine the results of studying the structure of atomic nuclei and the nature of nuclear forces. Work on the creation of transwound elements is also described in detail.

The second and third issues contain articles on elementary particles. In addition, it talks about many individual types of particles - pions, neutrinos, antiprotons, antineutrons,

K-mesons, hyperons, resonances, their discovery, properties and the place they occupy in the microamp.

The fifth issue includes an article on macrosoptical effects and phenomena whose nature is fundamentally quantum in nature. This is primarily quantum electronics, which created molecular generators and successfully produced various radiations, ultra-precise atomic clocks. This also includes the recently discovered quantum phenomena associated with superconductivity and superfluidity, as well as the famous Mössbauer effect.

The sixth issue is entirely devoted to the problems of modern astronomy. It talks about new branches of astronomy - infrared, reptgen, neutrino, gamma and radio astronomy - and adding amazing information to them. What, for example, makes hail worlds—Galaxies—explode? Why do stars pulsate? How old is the Orin Nebula? What physical processes occur in the Large Magellanic Region? These are some of the problems discussed in this book.

Unfortunately, among the authors of the collections there were very many Soviet scientists, many of whom made a worthy contribution to the development of modern physics. In some articles, this contribution is not even acknowledged not only in the main text, but also in the applying editors.

Most of these collections are available. They were published in relatively small editions, and now they can only be found in libraries. But everyone who takes the trouble to read at least one of these books will feel the powerful breath of modern science with its intersecting solved and unresolved problems.

V. A. Leshkovce

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To the article “The Story of Quantum”
(pp. 6-15)

1. 9,8·10⁻⁷ ∂x/cm³.
2. 2.3·10⁻¹² ∂p ≈ 1.5 electron-volts.
   Maximum number of quanta: 1.7·10⁻¹² ∂p ≈ 1 electron-volt.
3. 4.4·10¹² quanta in one cubic centimeter.
4. Quantum energy: 9.6 kiloelectron-volts, electron energy: 0.1 kiloelectron-volt.

To the article “Continued Fractions”
(pp. 16-26)

1. λ = 5216,5.
2. [0; 1, 2, 3, 4, 5].
3. $\frac{5777}{1875}$.
4. a) [1; 1212⋯],

6. [2; 444⋯],
   b) [2; 2424⋯].

5. 6. $\frac{\sqrt{ab(ab-4)}-ab}{2a}$*.

To the article “What is a function”
(pp. 27-36)

1. Natural domain of definition:
   a) x ≠ 0; 6) x ≤ -1; x ≥ 1.
2. a) 9; 6) 8; b) 6.
3. a) 8; 6) 6; b) 9; d) 0.
4. 10⁷; 4⁷.
5. nⁿ.
6. f₁ and f₃ are reversible.
   13 and 14. The mapping coincides with the inverse one.
7. a) 1680; 6) 9240; b) 18 150=3⁹-3·2⁹+3
8. Aₙⁿ=n (n−1) … (n−m+1), if m≤n; Aₙⁿ=0 if m>n.
9. $\frac{28!}{(7!)^4}$.

*) This is the positive root of the equation
$$x = \frac{1}{a + \frac{1}{b+x}}.$$

To the article “Dry friction”
(pp. 37-43)

1. Let us decompose the friction forces acting on the front wheels automatically into two components: F₁, lying in the plane of the wheels, and F₂, perpendicular to the wheels (see figure). F₁ forces make the wheels turn, and F₂ forces turn automatically.

2. If the center of gravity of the stick is not in the middle between the fingers, then the pressure of the stick on the fingers is different. The friction forces acting on the stick from the fingers are also different. The stick moves to the side where there is less friction.

3. Until the block slides along the plane, the friction is equal in magnitude to the projection of the weight of the block onto the inclined plane F_TP = P sin α. The block begins to slip when the friction reaches its maximum rest value F_TP = kN = kP cos α. In this case, the condition kP cos α = P sin α is satisfied. Therefore, the sliding of the block begins at the angle of inclination of the plane to the horizon α = arctan k. After this, the friction will be equal to F_TP = kN = kP cos α.

The angle α = arctan k at which the block begins to slip is called the friction angle. It also has another geometric meaning: if a force is applied to a block lying on a horizontal plane that is less than the friction angle with the vertical, then the block cannot be moved from its place, no matter how much the applied force is applied. You can prove it like this. Let us place the observer on an inclined plane on which a block of wood lies.

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juice, and we will increase the angle of inclination of the plane to the horizon. The observable will say that in his coordinate system, a body lying on a plane, which he considers horizontal, is acted upon by a layer that makes an angle α with the redistribution to the plane. If tgα < k (i.e. α < arctg k), then the block does not slide along the plane, no matter how great the applied force.
4. The answer is shown at figure.

The drawing inserted into the slot will be pressed against the board by the ball. If the angle α formed by the inclined edge is passed vertically, such that tan2α < k (where k is the coefficient of friction between the ball and the drawing), then the drawing will be held by friction against the ball, no matter how large the weight of the drawing and no matter how small the friction

5. The cable acts on the rods with forces F1 and F2, the magnitude of which depends on the weight of the pipe. For example, if the rods make an angle with the overload to the surface of the pipe less than α = arctan k (k is the friction coefficient of the rods on the pipe), then the rods will not slide along the pipe, no matter how large the forces F1 and F2 are, and therefore no matter how large the weight of the pipe is (see solution to problem 3). In such cases, engineers talk about jamming.

Using wedging, you can make a simple and convenient lock for hanging maps and drawings. You need to make two metal circles, as shown in figure (p. 64, above), and, having nailed the circles to the board, put a ball into them.

drawing on the board. To remove the drawing from the lock, just lift the ball with a pointer.

6. The cube begins to slide when the equal force F and the component of the weight of the cube, parallel to the inclined plane,