Maxwell’s Demon is a thought experiment which Scottish physicist, James Clerk Maxwell proposed for confirming the validity of the second law of thermodynamics at 1867. According to the experiment, there are two separate rooms which their temperatures are very different than each other. They are divided by a wall at the center and there is a demon standing in the middle of this wall. This wall has also a super-sensitive door on it. The gases inside the rooms are always in motion and each particle of the gases are at a different temperature. The demon lets in hot molecules coming from the hot room to the cold room. And he also lets the cold molecules go to the hot room which are from the cold room. He can do this by opening and closing the door.
This process results in that one room continually warms up whilst the other one gets cold. However, the heat distribution must be uniform as the thermodynamics say to us. This phenomenon crosses over the second law of thermodynamics. Such a thing like this is impossible to happen at all. According to the second law of thermodynamics (entropy), the temperatures of the rooms must be balanced by the time.
