According to the second law of thermodynamics, what happens during energy transfer or transformation?

The second law of thermodynamics states that in any energy transfer or transformation, the total entropy of a closed system can never decrease over time. Instead, it will either remain constant or increase. Entropy is often described as a measure of disorder or randomness in a system. Consequently, for the universe as a whole, which can be viewed as a closed system, the overall entropy is always increasing. This reflects the natural tendency of systems to move towards a state of greater disorder.

Understanding this concept is crucial in many scientific and practical applications, such as in energy efficiency and understanding natural processes. For instance, when energy is transformed from one form to another, some energy becomes unavailable for doing work, leading to an increase in entropy. This principle is essential for recognizing the limitations of energy use and the directionality of thermodynamic processes.