Daniel Bernoulli: biography, photo, contribution to the development of probability theory

XVII century - the age of enlightenment. In many branches of knowledge, with the help of advanced minds, the religious basis of cognition of the world has been replaced by a purely scientific one. A unique phenomenon in this process is the Bernoulli family, which gave several world-class scientists at once. One of the brightest names from this galaxy is Daniel Bernoulli. The scale of the gift and the variety of scientific interests, he resembled the great scientists of the Renaissance. The main merit of his and other family members for future generations is to give the mathematician the role of a universal tool for research in various branches of science - in physics, chemistry, biology and many others.

Mathematics as a family business

The ancestors of the Bernoulli family were from Flanders, from that area of the Southern Netherlands, which later became part of Belgium. In Antwerp, where one of the forefathers of the famous family, Jacob, lived, the oppression of Protestantism began, including Bernoulli. They were forced to leave first to Germany, and then to Basel, where they obtained Swiss citizenship. The son of Jacob - Nicholas, who is marked on the family tree by the elder, had 11 children. He became the founder of the famous mathematical dynasty. One of the children of Jakob - Johann - taught at the University of Groningen. In this Dutch city on January 29, 1700, Daniel Bernoulli (1700-1782) was born.

When the future great scientist turned 5 years old, Johann Bernoulli and his family returned to Basel, where he received the post of professor of mathematics. After he began to engage in the education of Daniel, it became clear that he was gifted no less than his brothers - Jacob and Nicholas Jr.. But Johann expected Daniel to be a more profitable - merchant or medical - career, therefore, at his insistence, at the age of 15, Daniel Bernoulli began to study medicine first at the University of Basel, and then in German Heidelberg.

Medicine and Mathematics

Interest in the study of flows in the liquid and gaseous environment was manifested in Daniel, when he became a disciple of the famous English physician William Harvey. He carefully acquainted with his work on the study of blood flow in the human body - Harvey was the first to discover the large and small circles of blood circulation.

Soon Daniel Bernoulli defended his thesis and tried to get a teaching post. At that time, the choice of applicants was often made by lot. The young scientist's attempt was unsuccessful, but became the reason for his interest in the mathematical aspects of probability theory.

In 1724 Daniel moved to Venice to continue studying practical medicine from the famous doctor Antonio Michelotti.

Danila Ivanovich

In Italy, he was seriously ill, but continued his research. He conducted many experiments to find regularities in the behavior of water when it escaped from the container and passed through tubes of different cross-sections. This work created him an authority in a new field of physics, which he called hydrodynamics.

In 1725, Daniel Bernoulli received an invitation from the Russian Empress Catherine I to take the post of head of the department of mathematics at the Academy of Sciences of St. Petersburg. She also counted on his participation, as a prominent specialist in hydrodynamics, in the creation of a cascade of fountains in Peterhof.

The stay of the scientist in Russia was marked by a tragedy - nine months after his arrival in St. Petersburg, his brother Nikolai, who had come with him, died from fever. Despite the severe morale that accompanied him during his stay in a foreign country, Daniel accumulated material for his main scientific work, Hydrodynamics, published in 1738. It formulated the main provisions of laws that determine the nature of flows in liquids and gases, named after Bernoulli.

The yearning for the house made the scientist apply for a position in Basel, where Daniel Bernoulli returned in 1733. His biography has since been associated only with this city, where he lived all his life until his death in 1782.

Relationship with father

When in 1734 Daniel gave his "Hydrodynamics" to the competition in the Paris Academy of Sciences, it turned out that his opponent was his father. The Academy's decision was a compromise, but angered by the parent. Daniel Bernoulli and Johann Bernoulli were declared equal winners, but finding one step with the son seemed humiliating for the old professor.

Daniel's relationship with his father was broken, despite the son's desire to establish them. At the publication of "Hydrodynamics" in Strasbourg in 1738, he pointedly added to his name on the title page "son of Johann." But the older Bernoulli was irreconcilable. A year later, his book Hydraulics was published. He specifically dated it in 1732 to indicate his priority.

Daniel Bernoulli and his contribution to the development of probability theory

In the "Comments of the St. Petersburg Academy," Bernoulli published a paper in which he considered an assertion called the St. Petersburg paradox. It concerned the game first mentioned by Daniel's nephew, Nikolai: when the coin is n-folded, the dropped "eagle" brings the player a winnings of 2 to the power of n coins. Mathematical calculation of the probability of winning leads to an infinite value, but common sense shows that the reward for participating in the game must have a finite value. When solving the paradox, Daniel uses a substitute for the mathematical expectation of winning moral, as well as the relationship between probability and personal utility.

Another important study of Bernoulli in this area was related to the main profession of Daniel - the medical profession - and with new sections of science, mathematical statistics and error theory. He published a paper on the effectiveness of smallpox vaccinations.

Heritage

The work of Daniel Bernoulli in the theory of differential equations is highly appreciated by "pure" mathematicians. And mathematical physics is a branch of science, where a scientist is considered one of the founders.

A real universal physicist, in addition to the fundamental laws of hydrodynamics, Bernoulli enriched the kinetic theory of gases and the theory of elasticity, to which a whole series of works on string vibrations is devoted. Modern aerodynamics is also based on findings first made by Daniel.

Paris, Berlin, Bologna, St. Petersburg Academy of Sciences, London Royal Society - a member of these scientific associations was Daniel Bernoulli. The photo with his portrait adorns the walls of many scientific institutions bearing his name, including a laboratory at the Institute of Mathematical Research of Complex Systems at Moscow State University.