XVII century - the age of enlightenment. In many branches of knowledge, by the forces of advanced minds, the religious basis of knowledge of the world was replaced by a purely scientific one. A unique phenomenon in this process is the Bernoulli family, which produced several world-class scientists at once. One of the brightest names from this galaxy is Daniel Bernoulli. By the scale of his talent and the diversity of his scientific interests, he was reminiscent of the great scientists of the Renaissance.
The main merit of him and other family members to future generations is to give mathematics the role of a universal tool for research in various branches of science - in physics, chemistry, biology and many others.
Math as a family business
The ancestors of the Bernoulli family were from Flanders, from that region of the Southern Netherlands, which later became part of Belgium. In Antwerp, where one of the progenitors of the famous family, Jacob, lived, the oppression of supporters of Protestantism began, which included Bernoulli. They were forced to leave first for Germany, and then for Basel, where they received Swiss citizenship. Jacob's son - Nikolai, whothe family tree of the family is designated the Elder, had 11 children. He became the founder of the famous mathematical dynasty. One of Jacob's children, Johann, taught at the University of Groningen. Daniel Bernoulli (1700-1782) was born in this Dutch city on January 29, 1700.
When the future great scientist was 5 years old, Johann Bernoulli and his family returned to Basel, where he received the post of professor of mathematics. After he began to educate Daniel, it became clear that he was no less gifted than his brothers, Jacob and Nikolai Jr. But Johann assumed for Daniel a more profitable career - a merchant or a doctor - therefore, at his insistence, from the age of 15, Daniel Bernoulli began to study medicine, first at the University of Basel, and then in Heidelberg, Germany.
Medicine and mathematics
Daniil became interested in studying flows in liquid and gaseous media when he became a student of the famous English physician William Harvey. He carefully read his work on the study of blood flow in the human body - Harvey was the pioneer of the large and small circles of blood circulation.
Soon Daniel Bernoulli defended his dissertation and tried to get a teaching post. At that time, the choice of applicants was often carried out by lot. The attempt of the young scientist 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 with the famous physician Antonio Michelotti.
DanilaIvanovic
In Italy, he fell seriously ill, but continued his research. He conducted many experiments to find patterns in the behavior of water as it flows out of a container and passes through pipes of different sections. This work gave him authority in a new field of physics, which he called hydrodynamics.
In 1725, Daniil Bernoulli received an invitation from the Russian Empress Catherine I to take the position 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 scientist's stay in Russia was marked by a tragedy - 9 months after his arrival in St. Petersburg, his brother Nikolai, who had come with him, died of a fever. Despite the difficult morale that accompanied him during his entire stay in a foreign country, Daniel accumulated material for his main scientific work, Hydrodynamics, published in 1738. It formulated the main provisions of the laws that determine the nature of flows in liquids and gases, which received the name of Bernoulli.
Sickness at home forced the scientist to apply for a position in Basel, where Daniel Bernoulli returned in 1733. Since then, his biography has been associated only with this city, where he lived without a break until his death in 1782.
Relationship with father
When in 1734 Daniel submitted his "Hydrodynamics" to the competition at the Paris Academy of Sciences, it turned out that his rival was his father. The decision of the Academy wascompromising, but angered by the parent. Daniel Bernoulli and Johann Bernoulli were declared equal winners, but being on the same level with his son seemed humiliating for the old professor.
Daniel's relationship with his father was severed, despite his son's desire to fix it. When publishing "Hydrodynamics" in Strasbourg in 1738, he defiantly added "son of Johann" to his name on the title page. But the elder Bernoulli was uncompromising. A year later, his book "Hydraulics" was published. He specifically dated it to 1732 to indicate his priority.
Daniel Bernoulli and his contribution to the development of probability theory
In the "Commentaries of the St. Petersburg Academy" Bernoulli published a paper that de alt with the statement, called the St. Petersburg paradox. It concerned the game, first mentioned by Daniel's nephew, Nikolay: when flipping a coin n times, the dropped head brings the player a win of 2 to the power of n coins. The mathematical calculation of the probability of winning leads to an infinite value, but common sense shows that the reward for playing the game should have a finite value. When resolving the paradox, Daniel uses the replacement of the mathematical expectation of winning with the moral one, as well as the relationship between probability and personal utility.
Bernoulli's other important research in this area was connected with Daniel's main profession - medical - and with newsections of science, mathematical statistics and error theory. He published a paper on the effectiveness of smallpox vaccinations.
Legacy
The work of Daniel Bernoulli in the theory of differential equations is highly valued by "pure" mathematicians. And mathematical physics is a branch of science where a scientist is considered one of the founders.
A true physicist-universal, in addition to the fundamental laws of hydrodynamics, Bernoulli enriched the kinetic theory of gases and the theory of elasticity, which is devoted to a whole cycle of works on string vibrations. Modern aerodynamics is also based on the findings first made by Daniel.
Paris, Berlin, Bologna, St. Petersburg Academies of Sciences, the Royal Society of London - Daniil Bernoulli was a member of these scientific associations. A photo with his portrait adorns the walls of many scientific institutions bearing his name, including a laboratory at the Institute for Mathematical Research of Complex Systems at Moscow State University.
