The Second Law of Thermodynamics: Why Entropy Always Increases

The Second Law says natural processes move toward greater disorder, or higher entropy.
Spilled milk doesn’t jump back into the glass—entropy makes the mess irreversible.
Heat always flows from hot to cold, never the other way around without help.
Entropy is a measure of randomness, and the universe constantly trends toward it.
Engines can’t be 100% efficient because some energy always disperses as waste heat.
A melting ice cube shows entropy in action—orderly solid water becomes chaotic liquid.
Entropy explains the “arrow of time”—why we remember the past, not the future.
Living things fight entropy locally by using energy, but overall entropy still rises.
Stars burn fuel, spreading energy outward—an irreversible step toward cosmic heat death.
The Second Law shapes everything from aging bodies to the fading efficiency of machines.