The Laws of Thermodynamics: Feynman's Physics Explained
Thermodynamics rests on a few sweeping laws. The First Law is conservation of energy: you cannot get something for nothing. The Second Law is deeper still: the total disorder, or entropy, of the universe always increases. That is why heat flows from hot to cold, why you cannot unscramble an egg, and why perpetual motion is impossible. The Second Law even gives time its arrow.
The big idea
Disorder always increases — and that gives time its direction.
Think about it
A movie of a glass shattering looks wrong played backward. How does the Second Law explain that feeling?
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