# Daniel Bernoulli

Daniel Bernoulli published his masterpiece *Hydrodynamica* in 1738 only to see it plagiarized by his own jealous father. Bernoulli explained how the speed of a fluid affects its pressure – the Bernoulli Effect explains how an airplane’s wings generate lift. Bernoulli’s kinetic theory anticipated James Clerk Maxwell’s by more than a century, and Bernoulli carried out ground-breaking work on the theory of risk, utilized in areas as diverse as economics and evolution.

**Quick facts**

**FULL NAME : ** Daniel Bernoulli

**FAMOUS AS : **Mathematician

**NATIONALITY :** Swiss

**BORN ON :** 08 February 1700 AD

**BIRTHDAY :** 8th February

**DIED AT AGE :** 82

**SUN SIGN :** Aquarius

**PLACE OF BIRTH :** Groningen, Dutch Republic

**DIED ON :** 17 March 1782 AD

**PLACE OF DEATH :** Basel

**Major Works**

- His most remarkable work was the ‘Bernoulli’s theorem’, related to the field of hydrodynamics. It states, in effect, that the total mechanical energy of the flowing fluid, comprising the energy associated with fluid pressure, the gravitational potential energy of elevation, and the kinetic energy of fluid motion, remains constant. The theorem still forms the basis of many engineering applications, such as aircraft wing design.
- He also established the basis for the kinetic theory of gases and heat by demonstrating that the impact of molecules on a surface would explain pressure and that, assuming the constant, random motion of molecules, pressure and motion increase with temperature.

**Early Life and Education**

Daniel Bernoulli was a Swiss mathematician born on 29th January 1700 in Groningen, Netherlands. He belonged to a family of mathematicians. His father Johann Bernoulli was one of the first developers of calculus and his uncle and older brother are known as ‘by far the ablest of the younger Harpers’. At the age of 7, Daniel expressed his desire to study mathematics but his father encouraged him to study business instead. Daniel agreed on the condition that his father would tutor him in mathematics. His relation with his father was sour due to the shame that he felt after coming in the same place in a scientific contest in the University of Paris. He went as far as using plagiarism. Despite Daniel’s efforts of reconciliation, his father did not end the grudge till he died. In 1724, Daniel went to St. Petersburg to fill the post as Professor of Mathematics. He was, however, not satisfied there thus resulting in his resignation in 1733. He went back to the University of Basel. He was also selected as a Fellow of the Royal Society in May 1750.

**Carrier**

- In 1723-24, he published one of his earliest mathematical works titled ‘Exercitationes quaedam Mathematicae’ (Mathematical Exercises). It focused on differential equations and the physics of flowing water.
- In 1724, he was appointed the professor of mathematics at St. Petersburg academy of sciences, a post he served in for eight years. In 1733, after a temporary illness, he resigned from his post and returned to Basel.
- In 1732, he became a professor of botany and anatomy at the University of Basel and later, accepted a post in physiology in 1743.
- In 1738, he discussed the basis of the kinetic theory of gases in his work ‘Hydrodynamica’, which dealt with the properties of basic importance in fluid flow, particularly pressure, density, and velocity, and emphasized on their fundamental relationship.
- Subsequently, he came out with his most important work called ‘Bernoulli’s principle’, which states that the pressure in a fluid decreases as its velocity increases.In 1750, after being appointed to the chair of physics at the University; he served as the professor of physics for the next 26 years.
- He also published numerous papers dealing with mechanics which mainly focused on the problems connected with vibrating strings. He worked with Euler on elasticity as well as on the development of the Euler-Bernoulli beam equation.
- He also authored the ‘Specimen theoriae novae de mensura sortis (Exposition of a New Theory on the Measurement of Risk)’ which is the basis of economic theory of risk aversion, risk premium and utility.
- His later works comprised of statistics and probability. His last work involved the application of probability theory to various practical matters, such as inoculation and relative proportion of male and female births.

**Death**

Daniel Bernoulli was honored during his life for his immense contributions to mathematics and physics. He was an elected member of the leading scientific societies of that time such as those in St. Petersburg, Berlin, Bologna, Paris, London, Bern Zurich, Turin and Mannheim. Daniel had lost his interest in the field mainly due to his strife with his father which had remained unresolved till his death. Daniel died on 17th March 1782 when he was 82 years of age.

**Awards & Achievements**

- Between 1725 and 1749, he received 10 prizes from the Paris Academy of Sciences for his contributions in the field of astronomy, gravity, tides, magnetism, ocean currents, and the behavior of ships at sea.
- In May 1750, he was elected a Fellow of the Royal Society.

**Quotes and Sayings by Daniel Bernoulli**

It would be better for the true physics if there were no mathematicians on earth.

There is no philosophy which is not founded upon knowledge of the phenomena, but to get any profit from this knowledge it is absolutely necessary to be a mathematician.

Nature always tends to act in the simplest way.

**Some Unknown Facts About Daniel Bernoulli**

- He is mostly remembered for his claims of mathematics to mechanics, especially fluid mechanics, and for his ground-breaking work in probability and statistics.
- Bernoulli’s name is celebrated in the Bernoulli principle, a specific example of the conservation of energy, which describes the mathematics of the mechanism basic the operation of two important technologies used in the 20th century: the carburetor and the airplane wing.
- His earliest mathematical work was the Exercitationes or mathematical exercises which were published in 1724 with the help of Goldbach.
- Two years later he pointed out for the first time the recurrent appeal of resolving a compound motion into motions of translation and a motion of rotation.
- His chief work is Hydrodynamica, which he published in 1738; it resembles Joseph Louis Lagrange’s Mécanique Analytique because it was arranged so that all the results are consequences of a single principle, mostly the conservation of energy.
- This was trailed by a memoir on the theory of the tides, to which, resembled the memoirs by Euler and Colin Maclaurin.
- Bernoulli and Euler tried to discover more about the flow of fluids.

They mostly wanted to know about the relationship between the speed at which blood flows and its pressure. - To explore this, Daniel experimented by puncturing the wall of a pipe with a small open ended straw and noticed that the height to which the fluid rose up the straw was related to fluid’s pressure in the pipe.
- Physicians all over Europe were soon measuring patients’ blood pressure by sticking point-ended glass tubes directly into their veins.
- It was not until almost 170 years later in 1896 that an Italian doctor discovered a less painful method which is still used today.
- Bernoulli’s method of gaging pressure is still used today in modern aircraft to measure the speed of the air passing the plane; that is its air speed.
- To take his discoveries further, Daniel Bernoulli returned to his earlier work on Conservation of Energy.
- It was known that a moving body exchanges its kinetic energy for potential energy when it increases height. Bernoulli realized in a similar way that a moving fluid exchanges its kinetic energy for pressure.