French Engineer and Physicist Nicolas Léonard Sadi Carnot

Today is the birthday of French engineer and physicist Nicolas Léonard Sadi Carnot, born in the Luxembourg Palace in Paris (1796). He is often described as the "father of thermodynamics" for his work related to steam engines.

In 1824, Carnot published one of the first physics books written for general audiences, called Reflections on the Motive Power of Fire. It explained, in laymen's terms, the principles of converting heat to energy. Carnot argued that the real power behind an engine lay in the temperature difference between its hottest and coolest elements, and that the use of gas or fluid was irrelevant.

His work was eventually incorporated into the Second Law of Thermodynamics — one of the fundamental foundations of modern physics. Although it was initially used to develop the steam engine, the second law is now used to describe processes as diverse as how water is heated to make coffee, the expansion of the cosmos, and an ecosystem's food web. The English novelist and scientist C.P. Snow said, "Not knowing the Second Law of Thermodynamics is like never having read a work of Shakespeare."

Carnot was just 36 when he contracted cholera after an epidemic swept through Paris. Because doctors weren't sure at that time how the highly contagious disease was transmitted, much of Carnot's work was buried with him.
-Writer's Almanac