Entropy and probability are closely connected — entropy measures how likely or how “spread out” the possible arrangements (microstates) of a system are.
Here’s the idea in simple terms:
- Every system can exist in many different microscopic arrangements (microstates).
- Some arrangements are more probable than others.
- When there are many possible microstates that the system can occupy, it has high entropy — meaning it’s more disordered or random.
- When there are few possible microstates, the system has low entropy — meaning it’s more ordered or predictable.
In essence:
Entropy increases when the number of probable microscopic arrangements increases.
So, entropy is a measure of how probable a state is — the more ways something can happen, the higher its entropy.