Gaspard-Gustave Coriolis

French mathematician

• Born: May 21, 1792; Paris, France
• Died: September 19, 1843; Paris, France

Eighteenth-century French mathematician, engineer, and physicist Gaspard-Gustave Coriolis defined the concepts of work and kinetic energy for the physical sciences. Coriolis is most famous for his discovery of the Coriolis force, which helped physicists to better understand wind currents and weather patterns.

Primary fields: Mathematics; physics

Specialties: Mechanics; kinetics

Early Life

Gaspard-Gustave Coriolis was born in Paris, France, on May 21, 1792, the same year the French monarchy was abolished. His father, Jean-Baptiste-Elzéar Coriolis, was an officer in King Louis XVI’s army. He was forced to abandon his post in 1791, when Louis was captured by French revolutionaries and the armies of the monarchy disbanded. The Coriolis family fled to Nancy, a small city in the Meurthe-et-Moselle department of northeastern France.

Coriolis attended primary school in Nancy while his father worked as an industrialist. As a boy, Coriolis suffered from unknown ailments that remained with him throughout his life and led to frequent bouts of illness. Despite the fragility of his health, he was an accomplished student and entered the École Polytechnique in 1808. The school, established in Paris under the Napoleonic system, trained officials to serve in the French civil service. The sixteen-year-old Coriolis, who had an early affinity for mathematics, placed second among students taking the entrance exam for his year. After graduating with his basic degree, he attended the École des Ponts et Chaussées, also in Paris, where he pursued advanced training in mechanical engineering. Coriolis first worked as an engineer in Meurthe-et-Moselle and several other departments in northeastern France before devoting himself to academic research.

The death of Coriolis’s father placed a significant financial burden on Coriolis and his family, so he left engineering in search of more lucrative work. In 1816, mathematician Augustin-Louis Cauchy, who had recently been appointed to a professorship at the École Polytechnique, recommended Coriolis for a position with the university as a mathematics tutor. In 1829, Coriolis accepted a professorship at the École Centrale des Arts et Manufactures in Paris and left civil engineering for a life in academia.

Life’s Work

Coriolis made his first significant contributions to engineering research while he was working as a tutor at the École Polytechnique. During this time, Coriolis took an interest in mechanical engineering and ergonomics research, fields that were attempting to increase the efficiency of modern engineering projects. He contributed to the understanding of friction, which is the force that resists the motion of two objects as they move past one another. Research in this area was intended to aid in the design of machines with greater resistance to friction. Coriolis also wrote papers on ergonomics, proposing methods for designing machines that better fit the human body.

From his interest in mechanics and engineering, Coriolis began to develop theoretical models to explain the relationships between force and movement, and he soon realized the need to define the terminology surrounding the scientific understanding of energy transfer. Coriolis developed the concept of “work,” in the sense used by the physical sciences, conceptualized as the effect of a force over a certain distance. He also coupled the definitions of force and distance to create the concept of “kinetic energy,” which is defined in physics as the energy possessed by an object because of its motion.

By 1824, Coriolis had discussed the rudiments of his theories with fellow mathematicians Jean-Victor Poncelet, who was a military engineer and mathematician at a school in Metz, and Claude-Louis Navier, professor of applied mathematics at the École des Ponts et Chaussées. Both Coriolis and Poncelet published papers utilizing the newly-proposed definitions of work and kinetic energy in 1826 and 1829, though Poncelet acknowledged Coriolis’s role in creating the definitions. Coriolis’s 1829 publication Du Calcul de l’effet des machines (On the calculation of mechanical action) is considered the origin of his new scientific terminology. Over the ensuing years, Poncelet and Navier continued to study work and kinetic energy and their applications to physics and engineering. Coriolis also proposed a mathematical unit for work, which he called the “dynamode,” and which was used in several of his equations on the subject. However, the unit failed to gain popular acceptance.

In 1832, Coriolis accepted a position teaching applied mathematics alongside Navier at the École des Ponts et Chaussées. It was in this environment that Coriolis developed his most famous contribution to science, the discovery of what was later termed the “Coriolis force” or “Coriolis effect.” In his 1835 paper on the subject, “Sur les équations du mouvement relatif des systèmes des corps” (On the equations of relative motion of systems of bodies), Coriolis examined the relative fields of motion of objects with regard to a rotating field of reference. Though his discovery would later be applied to meteorology, Coriolis was primarily interested in the effects of motion in the rotating frames such as water wheels or the wheels used to facilitate vehicular movement.

The discovery of the Coriolis force hinged on Coriolis’s calculations regarding the application of physicist Isaac Newton’s laws of motion to objects moving within a rotating frame. Coriolis showed that the motion of an object within a rotating frame obeys Newton’s laws, but that an observer witnessing the movement of the object will note an apparent shift in the object’s original direction. This observational phenomenon, or effect, is why the term “Coriolis force” is used interchangeably with “Coriolis effect.” The illusion occurs because the object continues to move along a path relative to its initial trajectory, while the rotating surface beneath the object moves in a different direction.

Objects moving relative to a frame of movement that is rotating clockwise will appear to shift to the right, with regard to their original trajectory, while objects moving within a frame rotating in a counterclockwise direction will appear to shift to the left. While Coriolis calculated this phenomenon in its application to mechanical movement, later scientists observed that the Coriolis effect was active in a variety of anomalies that occurred because objects moving across the surface of the Earth were set in a rotating frame against the Earth’s direction of rotation on its axis.

Coriolis’s contributions to engineering research made him one of the most prominent figures in early nineteenth-century French academia. Upon the death of his colleague Navier in 1836, Coriolis was named to replace him as chair of the mathematics department at the École des Ponts et Chaussées. In 1838, he became director of studies at the École Polytechnique. Coriolis’s persistent health issues worsened as he aged, eventually bringing about his death, after a particularly violent bout of illness, on September 19, 1843.

Impact

The full impact of Coriolis’s research would not become apparent until after his death, when his theoretical models of rotating forces would allow meteorologists and geologists to develop a better understanding of how the rotation of the Earth affects the distribution of wind currents. The discovery of the Coriolis force was one of the key pieces of information needed to develop models of atmospheric currents and the distribution of weather patterns. Because the Earth serves as a rotating frame, wind currents moving across the surface of the planet appear to be deflected in a manner consistent with Coriolis’s interpretations. A full understanding of how the Coriolis force affects atmospheric dynamics was not apparent until later research methods confirmed Coriolis’s calculations.

As one of the leading intellectuals of nineteenth-century France, Coriolis helped to hone an approach to scientific research that would be reflected in subsequent generations of engineers and mathematicians in France and elsewhere. The concepts of work and kinetic energy proposed by Coriolis have become basic to the physical sciences and are utilized in physics, engineering, and a variety of other fields. In addition, in his positions at several of the most prestigious academic institutions in France, Coriolis helped to train the next generation of scientists who went on to disseminate the growing understanding of physical forces to the international scientific community.

Coriolis’s overall impact on science was later recognized and honored by the scientific community at large with the establishment of honors and awards in his name. One of the moon’s craters was named in honor of Coriolis, as well as an avenue in Paris. Coriolis’s legacy is particularly evident in France, where he is listed among the country’s most prominent pioneers of scientific research.

Bibliography

Ackerman, Steven A., and John A. Knox. Meteorology: Understanding the Atmosphere. 3rd ed. Sudbury: Jones, 2012. Print. Introduces the major concepts in meteorology and its relationship to Earth science. Includes the Coriolis force and its function in predicting weather patterns and atmospheric circulation. Illustrations, glossary, index.

Fahy, Frank. Air: The Excellent Canopy. Chichester, UK: Horwood, 2009. Print. Covers the current understanding of air and Earth’s atmosphere. Discusses the Coriolis effect, its discovery by Coriolis, and its subsequent development as a technique in atmospheric physics. Illustrations, glossary, index.

Grometstein, Alan A. The Root of Things: Topics in Quantum Mechanics. New York: Kluwer, 1999. Print. Covers a variety of topics related to quantum physics. Includes the Coriolis effect and its relevance to a number of applied phenomena since its discovery. Diagrams, references, indexes.