Part 3/11:
Observations of natural phenomena — such as the rotation of planets or the behavior of gas molecules in a container — reveal that while many physical laws are time-reversible, the second law of thermodynamics is uniquely time-irreversible. Actions like scrambling an egg or mixing sugar into coffee exemplify processes that, when reversed, appear absurd. The second law asserts that in an isolated system, entropy can only increase, but it does not explain what exactly entropy is.