Fluid mechanics owes a lot of its early findings and theories to Swiss polymath Daniel Bernoulli. Daniel was born on February 8, 1700, in Groningen, the Netherlands, into a family of distinguished mathematicians. His father was Calculus pioneer Johann Bernoulli. The family moved to Basel, Switzerland, when Daniel was young. He was a contemporary and close friend of mathematician Leonhard Euler.
Despite early discouragement from his father to pursue maths, owing to its low financial returns, Daniel persevered in the subject. He is said to have had a bad relationship with Johann. Both of them entered and tied for first place in a scientific contest at the University of Paris. Johann banned Daniel from his house, allegedly being unable to bear the “shame” of Daniel being considered his equal. In 1724, Daniel went to St Petersburg, the Russian Empire, as professor of mathematics, and returned to the University of Basel, where he successively held the chairs of medicine, metaphysics, and natural philosophy until his death.
In May 1750, he was also elected a Fellow of the Royal Society. Throughout his life, Daniel made significant contributions to various scientific disciplines. His 1724 book ‘Mathematical Exercises’ solved differential equations and discussed pressure. He also developed ‘Bernoulli’s equation’, which is important for engineering and applied physics, and contributed to the kinetic theory of gases, which helped scientists later form modern atomic theory.
In his 1738 book, ‘Hydrodynamica’, Daniel described what is now known as ‘Bernoulli’s principle’, which states that “when fluid speed increases, pressure decreases”. This principle is the basis for aerodynamics and explains how aircraft can fly. Daniel also worked with Euler on elasticity and the ‘Euler–Bernoulli beam equation’. In 1760, Daniel created the first mathematical model in epidemiology, which showed how variolation could increase life expectancy in France. His work also influenced medicine, where his fluid flow research led to an early method for doctors to calculate blood pressure. He also worked tirelessly in the subjects of probability and statistics. Daniel Bernoulli died March 27, 1782, in Basel.
