There are many examples where entropy decreases. For example, if we put water in a freezer, the entropy of the water decreases as it cools down and turns into ice. And yet, one cannot violate the second law of thermodynamics.

Choose an example of entropy decreasing and explain why the second law of thermodynamics is not violated.

Answer

The second law of thermodynamics is not violated because the decrease in entropy of the water is offset by a greater increase in the entropy of the surroundings, leading to a net increase in the total entropy of the system.

Explanation

Let's consider the example of water freezing into ice. When water is placed in a freezer, it loses heat to the surroundings and its temperature decreases. As the water cools down and eventually freezes, the molecules become more ordered, and the entropy of the water decreases. However, the second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. In this case, the freezer is not an isolated system. The heat removed from the water is transferred to the surroundings (the freezer and the external environment), which increases the entropy of the surroundings. The increase in entropy of the surroundings is greater than the decrease in entropy of the water, resulting in a net increase in the total entropy of the system (water + surroundings). Therefore, the second law of thermodynamics is not violated.