Explore a comprehensive physics lesson on entropy and the Second Law of Thermodynamics. Begin with a conceptual understanding of entropy as a measure of disorder, then delve into the Second Law and its implications for spontaneous processes. Learn formal mathematical definitions and equations for calculating entropy changes in various scenarios, including isothermal expansion, compression, and adiabatic processes. Discover the relationship between entropy and microstates, understanding how disorder correlates with higher entropy. Conclude with an in-depth look at heat engines, thermal efficiency, and the Carnot Cycle, examining the theoretical limits of engine efficiency and the four-step process of the ideal Carnot engine. Gain practical knowledge through example calculations and clear explanations of complex thermodynamic concepts.