Daniel Bernoulli facts for kids
Quick facts for kids
Daniel Bernoulli
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Portrait of Daniel Bernoulli (1720-1725)
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| Born | 8 February 1700 |
| Died | 27 March 1782 (aged 82) Basel, Republic of the Swiss
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| Nationality | Swiss |
| Education | University of Basel (M.D., 1721) Heidelberg University University of Strasbourg |
| Known for | Bernoulli's principle Early kinetic theory of gases Thermodynamics |
| Scientific career | |
| Fields | Mathematics, physics, medicine |
| Thesis | Dissertatio physico-medica de respiratione (Dissertation on the medical physics of respiration) (1721) |
| Influenced | Bernoulli University |
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Daniel Bernoulli (born February 8, 1700 – died March 27, 1782) was a brilliant Swiss mathematician and physicist. He came from the famous Bernoulli family in Basel, known for many great mathematicians.
Daniel is best known for using math to understand how things move, especially how liquids and gases flow. He also did important work in probability and statistics. His most famous discovery is Bernoulli's principle. This principle helps explain how things like carburetors work and how airplane wings create lift. It's a special example of how energy is always conserved.
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Early Life and Family
Daniel Bernoulli was born in Groningen, a city in the Netherlands. His family was full of famous mathematicians. The Bernoulli family originally came from Antwerp, which was then part of the Spanish Netherlands. They moved to escape religious persecution. After a short time in Frankfurt, they settled in Basel, Switzerland.
Daniel's father was Johann Bernoulli, who helped develop calculus. His uncle, Jacob Bernoulli, was an early expert in probability theory. Daniel had two brothers, Niklaus and Johann II. People often said Daniel was the most talented of the younger Bernoullis.
Daniel had a difficult relationship with his father. Once, they both entered a science competition and tied for first place. His father, Johann, was so upset that Daniel was considered his equal that he banned Daniel from his house. Johann even copied some of Daniel's ideas from his book Hydrodynamica into his own book, Hydraulica. He even changed the date on his book to make it seem like he published first! Daniel tried to make up with his father, but his father held a grudge until he died.
When Daniel was young, his father wanted him to study business. His father thought there wasn't much money in being a mathematician. But Daniel really wanted to study math. He eventually agreed to study business, and then later, medicine. He only agreed to medicine if his father would teach him math privately. Daniel studied medicine at several universities and earned his PhD in anatomy and botany in 1721.
Daniel was also a close friend of another famous mathematician, Leonhard Euler. In 1724, Daniel became a math professor in St. Petersburg, Russia. However, he was not happy there. He got sick, and there were problems with censorship and his salary. So, in 1733, he left St. Petersburg. He returned to the University of Basel in Switzerland. There, he taught medicine, metaphysics, and natural philosophy until he passed away.
In 1750, he was chosen to be a Fellow of the Royal Society in London. This was a great honor for scientists.
Mathematical Discoveries
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Daniel's first math book was Exercitationes (Mathematical Exercises), published in 1724. In this book, he showed how to break down complex movements into simpler parts.
His most important work was Hydrodynamica, published in 1738. This book was special because it showed how all the ideas about fluid motion came from one main rule: the conservation of energy. He also wrote about the theory of tides, which won a prize from the French Academy. His work on tides was very important, building on the ideas of Isaac Newton.
Daniel and his friend Euler worked together to understand how fluids flow. They especially wanted to know how the speed of blood flowing relates to its pressure. Daniel did an experiment where he poked a small straw into a pipe. He noticed that the height the fluid rose in the straw showed how much pressure was in the pipe.
Doctors in Europe soon started measuring blood pressure using a similar method. They would put glass tubes directly into patients' arteries. Luckily, about 170 years later, in 1896, an Italian doctor found a much less painful way to measure blood pressure. This method is still used today! However, Daniel's original idea for measuring pressure is still used in modern airplanes. It helps measure how fast the air is moving past the plane, which is called its air speed.
Daniel took his discoveries further by looking at the conservation of energy again. He knew that a moving object trades its movement energy (kinetic energy) for height energy (potential energy) as it goes up. Daniel realized that a moving fluid does something similar. It trades its movement energy for pressure. This idea became what we now call Bernoulli's principle. It's written as a math equation:
In this equation, P is the pressure, ρ is how dense the fluid is, and u is its speed.
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A 1738 copy of Bernoulli's Hydrodynamica
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First page of the first section of a 1738 copy of Hydrodynamica
Economics and Statistics
In his 1738 book, Specimen theoriae novae de mensura sortis (A New Theory on Measuring Risk), Daniel Bernoulli offered a solution to a famous puzzle called the St. Petersburg paradox. This work helped create the idea of "utility" in economics. Utility means the personal satisfaction or benefit someone gets from something.
Bernoulli noticed that people don't always try to get the most money when making decisions that involve risk. Instead, they try to get the most "utility." He realized that getting more money gives people less extra satisfaction as they get richer. For example, an extra $100 means more to someone earning $10,000 a year than to someone earning $50,000 a year.
Daniel also did early work in statistics. In 1766, he studied information about smallpox to show that inoculation (an early form of vaccination) was effective.
Physics Contributions
In his book Hydrodynamica (1738), Daniel Bernoulli also laid the groundwork for the kinetic theory of gases. This theory explains how gases behave based on the movement of their tiny particles. He used this idea to explain Boyle's law, which describes how the pressure and volume of a gas are related.
He also worked with Euler on elasticity, which is about how materials stretch and bend. They helped develop the Euler–Bernoulli beam equation, which is used to design strong structures. As mentioned, Bernoulli's principle is very important in aerodynamics, the study of how air moves around objects like airplanes.
In 1753, Daniel Bernoulli was the first to clearly state the Superposition principle. This principle says that the total movement of a vibrating system is a combination of all its individual vibrations.
Works
- Pieces qui ont remporté le Prix double de l'Academie royale des sciences en 1737 (1737)
Legacy
In 2002, Daniel Bernoulli was honored by being inducted into the International Air & Space Hall of Fame at the San Diego Air & Space Museum.
See also
- Bernoulli's principle
- Euler–Bernoulli beam equation
- St. Petersburg paradox
- Hydrodynamica
