High School Physics + more

Entropy as Probability – most disorder state is the most probable one

In this post, we will discuss how we can consider Entropy as Probability. We have already covered entropy (disorder) when we discussed the 2nd law of Thermodynamics.

There is a statistical explanation of entropy that says that the most disorder state is the most probable one. We will present this with the example of the flipping of 2 coins.

Suppose you flip two coins at once. Let’s list the possible outcomes.

We’ll use T=tails and H=heads

One possibility for two tails: TT

One possibility for two heads: HH

Two possibilities for one head and one tail: TH or HT

There are a total of four possible outcomes with a 25% chance of getting two tails and a 25% chance of getting two heads. But there is a 50% chance of getting one head and one tail.

The more organized states (those above with a 25% probability) have a lower probability of occurring.

The most probable outcomes in the natural world are those with the greatest disorder.

A teacup falling and shattering is a disordered state and much more likely to occur than is a shattered teacup reconstructing itself into a more ordered state. 

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