Maxwell’s Demon

(ORDO NEWS) — It is surprising that the laws of thermodynamics and entropy, which are now considered the absolute foundation of modern physics, appeared in textbooks only in the 19th century.

This was due to the three titans of science of the day: Rudolf Clausius , Ludwig Boltzmann , and James Clerk Maxwell , who studied the kinetic theory of gases for years in an attempt to formulate the consequences of the motion of free particles.

They realized that although a higher gas temperature means a higher molecular speed, we are talking about statistics.

In the end, everything is mixed and averaged

We see the consequences every day. We all know that if you put one end of a metal rod in a red-hot furnace, after a while the heat will reach the other end. Moreover, none of us expects that half of the water in a pot on fire will begin to bubble, while the other will maintain room temperature.

Maxwells Demon 2

Each of the trillions of particles move in a completely random way, and it sounds absurd to group them into ordered groups. This natural tendency to evenly distribute energy in a system is still spelled out in capital letters in the content of the second law of thermodynamics.

Spontaneous ordering of complex systems – without the participation of an external factor – would be tantamount to a change in the course of entropy.

However, Maxwell decided to defy the laws of thermodynamics. The Scottish father of electromagnetism developed a provocative thought experiment and asked the favorite question of all theorists:

What if…

What if, in spite of everything, there was a device capable of effectively separating individual molecules? The scientist’s proposal was as follows.

We place a tiny demon in a box filled with gas of a certain temperature. In the center of the container there is a partition with one hole through which only one molecule can be squeezed out at a time. Our imaginary demon acts as a porter here.

He opens the gate only on two occasions: when he sees a too fast particle approaching from one side, and when he sees an extremely “anemic” particle approaching from the opposite side. In all other situations, the door remains tightly closed.

Maxwells Demon 3

This is how Maxwell’s demon laughs at entropy, gradually sorting the molecules of a gas so that the fast ones go one way and the slow ones the other.

The scenario we excluded earlier is being implemented. A box filled with a gas of uniform temperature is now half cold, half hot. System entropy has decreased!


Contact us: [email protected]

Our Standards, Terms of Use: Standard Terms And Conditions.