What does the second law of thermodynamics state?

The second law of thermodynamics states that the entropy of an isolated system tends to increase over time. This principle reflects the natural progression toward disorder in energy transformations and spontaneous processes. In thermodynamics, entropy is a measure of the amount of energy in a physical system that is not available to do work. As energy transformations occur, there are always inefficiencies and dispersions of energy that lead to an increase in the overall entropy of the system.

In an isolated system, where no energy or matter is exchanged with the surroundings, the tendency towards increased entropy implies that the system evolves towards a state of maximum disorder. This is why, in practice, many processes — such as the melting of ice in a warm environment or the diffusion of a gas in a container — result in an increase in entropy, aligning with the second law.

The other concepts presented do not accurately represent the second law. The idea that energy cannot be created or destroyed relates to the first law of thermodynamics, while the notion that entropy decreases does not hold true for isolated systems. Achieving thermal equilibrium does involve entropy considerations, but it’s more about the distribution of energy rather than the overall change in entropy throughout the process. Thus, the correct assertion aligns with the understanding that entropy increases in