We all know that entropy is the measure of chaos in the system, and it\'s always

Question

We all know that entropy is the measure of chaos in the system, and it's always increasing in the system.

Now comes my question - how does entropy work in smart materials? Here is a youtube video about smart material that I'm talking about, it remembers its shape - you can distort it, but when you heat it, it returns back to its original shape. So effectively it reverses from more chaotic state to a more uniform state:

Therefore my question - how come the system became less chaotic just by adding heat? It looks like entropy decreased, but the 2nd law of thermodynamics says that entropy can only increase.

Explanation / Answer

The law that entropy always stays constant or increases applies only to closed systems.

This material gets more ordered at the price of greater disorder in the closed system : energy generator + material.

It is the same with crystals, crystallizing out of a solution. They are highly ordered but the energy expelled to the total "solution +crystal" increases the entropy of the closed system.

And the paramount example are living things. They are highly ordered, but not a closed system. They continually absorb and expel energy to the surrounding environment increasing the entropy of a "living system" + "energy source" closed system.

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