# THE DEMON THAT CHALLENGED THERMODYNAMICS:

Thermodymanics is one of the most essential fields in the study of Physics which establishes relationship between  physical quantities  like work,energy,heat and temperature etc. One of the pioneers in this field of research was Fellowship of UK Royal Society awardee James Clerk Maxwell who had some important contributions  to the field,one of them being ,the most debated and often questioned:Maxwell’s demon .

## MAXWELL’S DEMON:

Well,this demon doesn’t belong to any cult or anything. It’s just the part of the thought experiment devised by James Clerk Maxwell where entropy decreases. You’ll be now wondering how entropy can decrease! It always increases, right? If the entropy here decreases  ,then it certainly violates the second law of thermodynamics.Well nothing like this is gonna happen.
The thought experiment involves two gas chambers placed adjacent to each other with a door in between them controlled by  a being or a creature called the demon.Both the gas chambers ,say A & B, have particles moving at both high and low speeds.So when the demon sees the fast moving particles of chamber A approaching the door, he opens it so that they’ll flow to the other chamber ,i.e.,B.Again when he observes the slow moving particles approaching the door ,he opens so that they will move to A.Well what happens here is, now the A chamber has all the particles moving slow and vice versa for chamber B. As the faster moving molecules are hotter ,they increase the temperature of chamber B ,and the slower ones decrease the temperature of chamber A,all occurred due to the Demon’s behaviour.Hence this occurrence decreases the entropy ,thereby violating the second law of thermodynamics which states that two bodies at different temperatures in an isolated system when brought to contact with each other ,will evolve to a thermodynamic equilibrium in which both bodies have approaximately equal temperature.Also in an isolated system,entropy never decreases.But here in case of Maxwell’s demon,the entropy decreases which has attracted most debates in last decades.