The topic of this final work is related to the possibility of performing a kind of device called “perpetuum mobile of seconde species,” i.e. Maxwell's demon, and explained why it is not possible. The first part or introduction of the work gives a short history of James Clerk Maxwell, the author of this experiment, and the first appearance of the Maxwell demon in the public. In addition, the findings of Maxwell in this field of physics and its equation showing the course of еlеktričnog and magnеtskog fields and setting the principles of promjеna in the еlеktričnom field are presented. After that, in the second parts, a review of I. and II. The law of thermodynamics in order to explain as clearly as possible why this experiment cannot be realized in practice. The third part describes Maxwell's demon in detail. How in theory it works and what its purpose is. The criticism that emerged after the publication of the experiment is further elaborated. Explained factors influencing the experiment and their impact on the experiment.