## Quick Reference

(1792–1843) French physicist

Coriolis, a Parisian by birth, studied and taught at the Ecole Polytechnique, becoming assistant professor of analysis and mechanics in 1816. He was the first to give precise definitions of work and kinetic energy in his work Du calcul de l'effet des machines (1829; On the Calculation of Mathematical Action) and he particularly studied the apparent effect of a change in the coordinate system on these quantities.

From this latter research grew his most famous discovery. In 1835, while studying rotating coordinate systems, he arrived at the idea of the *Coriolis force*. This is an inertial force which acts on a rotating surface at right angles to its direction of motion causing a body to follow a curved path instead of a straight line. This force is of particular significance to astrophysics, ballistics, and to earth sciences, particularly meteorology and oceanography. It affects terrestrial air and sea currents; currents moving away from the equator will have a greater eastward velocity than the ground underneath them, and so will appear to be deflected. The idea was developed independently by William Ferrel in America.

In 1838 Coriolis stopped teaching and became director of studies at the Polytechnique, but his poor health grew worse and he died five years later.

*Subjects:*
Science and Mathematics.