Émilie du Châtelet, who hypothesized conservation of energy, established kinetic energy as distinct from momentum and proportional to (speed)², and combined work by Newton and Leibniz with her own original ideas in "Institutions de Physique," was born #OTD in 1706.

Du Châtelet is an important figure in the development of classical physics, but she is not nearly as well known as many of her male contemporaries.

Portrait: M. Q. de La Tour