Part 3/9:
In this thought experiment, a box filled with gas at constant temperature (T) is divided by a partition equipped with a small door. Initially, the gas is in thermal equilibrium, but the demon, possessing the unique ability to selectively allow gas molecules to pass through the door, manages to create a temperature difference between the two sides of the box. By moving only fast-moving molecules to one side and slow-moving ones to the other, the demon appears to violate the second law of thermodynamics by effectively decreasing the system's overall entropy.