1824Reputable sourceWell documented
Carnot and the Science of Heat
On the timeline · around 1824 ·
What happened
In 1824 the young French engineer Sadi Carnot, trying to understand why steam engines waste so much of their fuel, worked out the fundamental limits on turning heat into work. His idealized 'Carnot engine' showed that no engine can be perfectly efficient, and that the best possible efficiency depends only on the temperature difference the engine works across.
Why it matters
Carnot founded the science of thermodynamics and planted the ideas that led to the concept of entropy and the second law. His analysis governs every engine, refrigerator, and power plant ever built.