The book "Physics, told at night"

Physics has an incredible biography. You can find everything in it: successes and failures, hopes and shattered dreams, the machinations of ill-wishers and envious, creative impulses and fortitude.

In this book you will not find a single formula, but you will learn about great physical ideas and especially about the people who stand behind them: from Newton and Galileo to Einstein, Feynman, Fermi and Bohr; from Faraday and Maxwell to Schrödinger, Dirac, Heisenberg and Pauli; from the beginnings of science to the problems of time and space, the nature of light and heat; from the discovery of the atom to the principles of quantum mechanics; from observations of the starry sky to the fundamental ideas of modern astronomy and cosmology.

Excerpt from a book
Amazing substances or is it just a movement?

When Feynman was in his first year, he often heard discussions of his senior roommates on the problems of mathematics and physics. Once, two of them tried unsuccessfully to solve a problem in theoretical physics. Feynman's solution to this problem seemed clear, and he suggested “using the Baronallai equation.”

The family name Baronallai did not tell Feinman’s comrades about the room. Feynman learned about this equation from the Encyclopedia Britannica, but did not know how to pronounce the last name correctly. After it turned out that they were talking about the Bernoulli equation, the problem in physics was really quickly solved - and very soon Feynman became famous as the genius of mathematics.
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The Bernoulli family in mathematics is like the Bach family in music. For four generations she has given eleven outstanding mathematicians: four Nikolaus, three Johann, two Jacob, two Daniels. At the same time, one of Daniel Bernoulli was not only a famous mathematician, but also made a significant contribution in the field of physics.

Once during a trip to Europe during a conversation with strangers, Daniel Bernoulli introduced himself. “Then I,” his interlocutor answered, “Isaac Newton.” Daniel Bernoulli gladly told this story, because he saw in her a sincere display of respect for him.

In his "Hydrodynamics", published in 1738, Daniel Bernoulli successfully applied Newton's laws to liquids and gases. At the same time, Bernoulli, of course, proceeded from the fact that gases consist of atoms — from a myriad of small solid particles that are in constant motion, more or less unhindered move past each other and at the same time hit the walls of the vessel, causing way the gas pressure.

In a glass vessel of larger volume containing the same number of atoms, the gas pressure is less, since the collision with the vessel walls occurs less frequently. Bernoulli took up the specific question of how gas pressure would change if the side length of a cubic vessel was doubled, which would accordingly lead to an eight-fold increase in the volume of the vessel. Since then the opposite walls of the vessel will be located further each other and, therefore, the particles will have to overcome twice as much distance from one wall to another, then, therefore, they will be twice less likely to hit the vessel walls. However, since at the same time the surface of the vessel walls will become eight times larger, the gas pressure will generally decrease by one eighth of the original value. If, on the contrary, to reduce the volume of the vessel by half, then the pressure as a result of the correspondingly frequent blows of particles against the vessel walls will double the initial value.

About seventy years before, Robert Boyle, learning about the experiments of Otto von Guericke, also wanted to devote himself to this amazing vacuum. Together with Robert Hooke, he established that this more or less airless space transmits light and electrical forces unchanged, but cannot conduct sound and that combustion processes cannot occur in it. Until that time, all research concerned only the vacuum. Then Boyle’s acquaintance, theologian, Jesuit father Linus prompted him to experiment not with vacuum, but with the air itself. The reason for this was Linus’s doubts. The Jesuit father considered the experiments of Guericke improbable. Linus thought that if the air could be rarefied, then it should also shrink. However, this, in his opinion, was absurd.

Boyle took up the consideration of this idea and conducted his "New physico-mechanical experiments concerning the elasticity of air and its effects." Indeed, in 1660, Boyle presented a table, the data of which showed that when the volume was reduced by half, the gas pressure doubled.

Boyle saw the reason for the increase in gas pressure in small, springy particles located on top of each other: during compression, the gas pressure increased, as if during compression of a box filled with rubber balls. Newton also believed that gas pressure is caused by resting, but repulsive particles. Only Daniel Bernoulli put forward the right idea - about moving particles. It was Bernoulli who managed to find the right relationship between pressure and volume. However, his idea was not successful.

In his Physics, Aristotle spoke of the following four elements: fire, water, earth, and air. However, at the same time, Aristotle did not mean the real substances themselves or the fire itself. The elements — water, earth, and air — although reminiscent of the aggregative states — are liquid, solid, and gaseous, but have no analogies in the world around us. When at the beginning of the 18th century, Georg Stahl suggested that when burning a body, phlogiston is released - from the Greek “combustible” - and turns into fire, for many this element - fire - has acquired its specific form.

The more phlogiston the body contained, the better it burned. In this case, the burning was represented as the separation of two substances. After some time, it became clear that when burned, the body becomes heavier. What at first glance might have looked like a contradiction was resolved with the help of an artificial device: negative mass was attributed to phlogiston — thus, an explanation was given why the fire goes up.

Antoine Lavoisier saw it completely differently - and as a result he became one of the founders of modern chemistry. Lavoisier believed that the combustion did not result in the separation of two substances, but, on the contrary, their combination. In combustion, he saw the union with oxygen and thus was able to explain why the body becomes heavier during combustion. At the same time, he found a convincing tool for answering an ancient question about the difference between an element and a compound. If a substance can chemically turn into substances that are heavier than itself, then, according to Lavoisier, it is a chemical element.

When in 1789, in the year of the French Revolution, Lavoisier published his new theory of chemical elements, there were already twenty-three.282 Among these twenty-three elements was a substance that today is not counted as an element — a calorie. Thermal energy, however, was not Aristotelian fire, but a substance of heat, which Lavoisier considered as part of chemical reactions.

For Joseph Black, who lived at the same time as Lavoisier, caloric was an elastic fluid. This view seemed to make some phenomena well understood. From this point of view, caloric penetrates into the heated body. This is noticeable when stretching the body. During compression, the gas gives off perceptible heat, as the caloric is squeezed out of it. During evaporation, the substance absorbs caloric, and during condensation, the caloric is released again as heat of condensation. To melt the ice, you need heat. When the ice freezes, it gives off that heat.

Earl Rumford doubted the existence of caloric acid. For a long time, during careful measurements, he tried in vain to determine the weight of heat, the weight of caloric. Instead of simply assuming that heat, like light and electricity, has no weight, Rumford, in the negative outcome of his experiments, saw an indication that “heat is nothing but an internal, vibrating motion of the particles that make up a heated body ".

Rumford made this assumption, having a good basis for this. In 1798, in Munich, at his request, gun barrels were drilled with blunt steel drills in artillery workshops at his request. Hot hot drills were immersed in water every now and then. Thus, using the same drill, the water was boiled for several days and weeks. As a result, it became quite obvious that heat cannot be a substance, since in this case it would one day have to exhaust itself. Obvious for Rumford was also what was actually warm: since it was continuously formed by movement, then, according to Rumford, it itself had to be part of the movement.

Earl Rumford failed to convince the scholars of his time. Reflecting on heat, physicists of that era considered it not in the form of tiny particles in constant motion, but still in the form of an amazing substance.

Daniel Bernoulli saw particles in constant motion as the cause of gas pressure. For Count Rumford, this movement manifested itself additionally as heat. The kinetic theory of warmth, from the Greek word kinema, meaning motion, was created from the ideas of Bernoulli and Rumford. In particular, this way physics came to the discovery of the atom. However, this became possible thanks to another huge breakthrough in physics, namely the discovery of the law of conservation of energy.

»More information about the book can be found on the publisher's website.
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