Maxwell’s Demon: How to defeat entropy

Demon2If you’ve ever studied the topic of energy at school, you might have heard of “entropy”. It’s basically another name for disorder in the universe. For example if you mix milk in your tea, no matter how hard you try you can’t get all of it out. So you can’t get back all of the energy spent mixing the milk.

This happens with every other process as well. When petrol burns in a car, some of it’s energy is wasted as heat and when you run, some energy is used in your body to make sweat. So in every process some energy is wasted and the disorder in the universe increases. Imagine that you could stop this.

James Clerk Maxwell, the scientist who wrote down the equations for electricity and magnetism, thought up a demon, who could stop disorder in it’s tracks.

James Clerk Maxwell
James Clerk Maxwell

Imagine two rooms with a door in between. One room is empty and the other room has a gas in it. Now imagine there’s a little demon at the door and whenever a hot molecule of the gas comes near the door he opens it and the molecule goes in to the other room. GW250H275He does this for all the hot molecules in the gas so that one room now contains all hot gas and the other contains cold gas. Well that’s it! One room has heated up and the other has cooled down. No energy has been wasted. Entropy has been defeated.608px-Maxwell's_demon.svg

Of course this is just imagination. But maybe some day we’ll figure out what to do to reverse disorder and defeat entropy. Until then, Maxwell’s demon eludes us.

By Mohammad Yousuf Mehmood

NSS-Director Publications


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