The Physical Worldornament
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The Restless universe
Introduction to The restless Universe

1 The lawful Universe

2 The clockwork Universe

3 The irreversible Universe

4 The intangible Universe

5 The uncertain Universe

6 Closing items


Other titles in the Physical World series

Describing motion

Predicting motion

Classical physics of matter

Static fields and potentials

Dynamic fields and waves

Quantum physics: an introduction

Quantum physics of matter

Answer and comments

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Question 1.3
When a room-temperature object is placed in a refrigerator, heat flows out of the object and its entropy decreases. Indeed, the refrigerator may be said to be a device for sucking entropy out of warm objects. How can such a decrease in entropy be consistent with the second law of thermodynamics?

Q1.3 By the second law of thermodynamics, the total entropy of the Universe must not decrease. The entropy of warm objects placed inside the fridge decreases as heat flows from them. At the same time, the back of the fridge is warm, so the surroundings of the fridge are warmed and their entropy is increased. The second law of thermodynamics is satisfied because the increase in entropy of the surroundings of the fridge is equal or greater in magnitude than the decrease in entropy of the fridge contents.

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