What does the second law of thermodynamics state?

The second law of thermodynamics states that the total entropy of a closed system can never decrease over time. In fact, it generally increases, meaning that systems tend to move towards a state of greater disorder or randomness. This principle is fundamental in understanding various natural processes, including heat transfer and the direction of chemical reactions. Entropy is often described as a measure of disorder; as energy transformations occur, some of that energy becomes less available to do work, leading to increased entropy.

The concept highlights that while energy can be transformed, not all energy is converted into useful work, and no energy can be created from nothing in isolated systems. This aligns well with the understanding of energy flow and efficiency in physical and biological systems. Thus, the statement that the entropy of closed systems always increases correctly reflects the implications of the second law of thermodynamics.