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Heat spreads unless work is done

Entropy describes how energy spreads and how many microscopic arrangements can produce the same overall state.

The idea

For an isolated system, total entropy cannot decrease. A refrigerator can lower the entropy of its contents while increasing the entropy of its surroundings by a greater amount.

An example

A refrigerator uses electricity to move heat from its cold interior to the warmer room, releasing the extracted heat plus the energy used.

Put it into practice

Cooling a room does not make heat disappear: the heat must go somewhere else, and moving it requires energy.

Further reading: Wikipedia ↗

Test yourself: How can a refrigerator create a cold interior?

It uses energy and releases more heat outside

Right. The refrigerator uses work to transfer heat to the room, releasing the extracted heat plus the energy it used.

Explanation and illustrative examples by One Card Wiser. Source linked for further reading.

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