Entropy and open systems

Local order can increase while total entropy increases. The boundary around the system matters.

The second law constrains the total entropy change of an isolated system. An open system exchanges matter or energy with its surroundings, so a local entropy decrease can be accompanied by a larger increase elsewhere. Living systems maintain organization through such exchanges.

For example: A refrigerator cools its interior by doing work and releasing heat into the room. Looking only inside the refrigerator misses the full accounting.

Keep in mind: Entropy has precise thermodynamic and statistical definitions. Calling it simply 'disorder' can mislead, and social analogies do not inherit a physical theorem.

Think about it

When someone claims a process creates order, what system boundary and energy flows would you inspect?

Connected ideas

Emergence from local rules · The map is not the territory · Symmetry and conservation

Sources and further reading

• OpenStax University Physics Volume 2: Entropy and the Second Law of Thermodynamics

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