# Physicist Daniel Bernoulli: biography, discoveries and interesting facts

Each student knows the name of Daniel Bernoulli, since the well-known formula is named after him. In the article we will consider life and scientific achievements and also talk about what his life was like.

## Family history

It is known that the genus of the scientist comes from Antwerp. Bernoulli was forced to settle in Frankfurt am Main, because they fled from the persecution of the Duke of Alba on religious grounds. In the century, the family moved to Basel. Interestingly, the next three generations were rich in talented mathematicians, of which three achieved almost world-wide fame.

## Daniel Bernoulli: the biography of childhood

The baby was born in the middle of the winter of 1700 in Holland, in the small town of Groningen. His father, Johann, was a teacher of mathematics. It was the father who instilled in the boy a love of science. Daniel and Johann Bernoulli worked together in mathematics in the walls of the Basel gymnasium.The boy learned not only from his father, but also from his brother Nicholas. However, Daniel had an interest in medicine.

It is interesting that the father, being a mathematician, wanted to raise a merchant from his son Daniel. Twice he arranged for him as a clerk, but everything was useless, because the wayward son wanted to go his own way in life.

## Training

In 1716 he received a master's degree from the University of Basel, where he studied at the Faculty of Philosophy. At the same time, the guy was a volunteer lecturer in medicine. As a result, he studied in Heidelberg and Strasbourg, learning the ins and outs of medical practice. In 1720, an ambitious guy with unique ideas returned to his native town of Basel. During the year he works on a thesis on physiological issues, in which he tries to describe everything in mathematical terms. Since 1723 he has been conducting active medical practice in Venice under the supervision of Michelotti. It is working as a doctor in Venice, a man writes and publishes his first work "Mathematical Studies", which brings him fame.

## Trip to Petersburg

What does Daniel Bernoulli do next? In short, his life is turned upside down. In 1725 he and his brother Nicholas were invited to Petersburg.There, by decree of the emperor, the Petersburg Academy of Sciences is being created. Young scientists are invited to conduct research. First, Bernoulli is actively engaged in medicine, but over time, he is increasingly attracted to mathematics, and he goes to the appropriate department after 3 years of life in the city on the Neva. A place at the mathematics department became accessible to him by tragic coincidence of circumstances - the death of Nicholas.

Just at this time begins distemper. Peter I dies, there is a mess in the country. Many foreign researchers who have been invited to the Academy are leaving or leaving. However, Daniel was not going to just give up. He invites Euler’s friend to Russia. Despite the fact that the invitation was sent in 1726, the comrade could arrive only in 1727.

Soon Catherine I dies and the government almost completely forgets the affairs of the Academy. In 1733, the man returns to Basel. At the same time he remains a member of the Academy. By the way, it was within its walls that he published 47 of 75 of his works. All his time in Russia was engaged in the preparation of the main work - the monograph "Hydrodynamics", which was published in 1738.Here published "Notes on recurrent sequences."

## Return to Basel

After returning to his native penates, the man gets a job as a professor of botany and anatomy. It is impossible to say that he really wanted this, but it was the only option. Despite the routine work, he does not abandon his main hobbies and is actively communicating with Euler. In 1738 he published his fundamental work, Hydrodynamics, which was mentioned above. It contains the law of Bernoulli. In the first edition of the book there were still no differential equations of fluid motion, since they were established only in the 1750s by Euler.

## Last years

From 1747 to 1753, the physicist produced a number of important works on string vibrations. Given the physical factors, Daniel decided to decompose the solution of the problem in a trigonometric series. He said that such a series is no less common than power. At first, his idea met with objections in the person of D’Alembert and Euler. However, this discussion was finally resolved only in the XIX century, and Daniel turned out to be right.

In 1748, a man joined the Paris Academy of Sciences as a foreign member. In 1750 he moved to the Department of Physics at the University of Basel. It works until the end of his days. For all the time he was twice elected rector.In the spring of 1782, a talented physicist died at his desk.

## Scientific activity

The scientist gained great fame in the field of the theory of differential equations and mathematical physics, the founder of which, together with D’Alamber and Euler, is considered to be his. A talented universal physicist was able to enrich aerodynamics, the theory of elasticity and the kinetic theory of gases. He was the first to express the opinion that the cause of gas pressure is the thermal movement of molecules. Daniel Bernoulli's equation is known to every student. It concerns the steady flow of incompressible fluid. This is what underlies the dynamics of gases and liquids. If we look at physics from the point of view of molecular theory, then we can say that Bernoulli explained in his own way the Boyle law — Mariotte.

The hero of our article belongs to the formulation of the law on the conservation of energy. Together with Euler, they simultaneously formulated the law of conservation of angular momentum. It was Bernoulli who for several years dealt with the question of elastic oscillations, after which he formulated the principle of superposition of oscillations and introduced such a concept as harmonic oscillations.

In 1746, a man proved that centrifugal force is not a real force. It directly depends on the choice of reference system.

Daniel Bernoulli wrote many significant works in mathematics concerning the theory of series, differential equations, probability theory and numerical methods. He was the first to resort to methods of mathematical analysis in solving problems on the theory of probability, because before that scientists had only used combinatorics. The scientist made a significant contribution to the development of mathematical statistics.

## Who is the author of the theory of probability?

What else is related to mathematics by Daniel Bernoulli? The theory of probability without his contribution would be insufficient. In its present form, the formula allows one to find the probability of an event in a series of independent tests. In this case, the advantage of the method is that it allows you to avoid a large number of calculations with a significant number of tests. However, it is named after Daniel, and in honor of Jacob Bernoulli. Daniel did not invent it, but only supplemented it. In the study of probability theory, the scientist used calculations of infinitely small quantities. In parallel with the research A.Moivre and Laplace published a table of random distribution. It was Daniel Bernoulli who determined the number e.

It is worth adding that in all his life a physicist has never been married. His relationship with his father has always been complicated. Throughout life, they ranged from strained to openly hostile. The essence was in disagreements about priorities in life and science.

The life of a universal physicist was full of consistent discoveries. Undoubtedly, his contribution is invaluable. However, the most impressive is the death of a dedicated man.