Entropy

Entropy measures the degree of disorder, uncertainty, or randomness in a system. In thermodynamics, it quantifies the unavailability of energy to do work, with the Second Law stating that entropy in isolated systems always increases over time. In information theory, entropy represents the average amount of information contained in a message or the unpredictability of a system. High entropy indicates greater disorder or uncertainty, while low entropy reflects order and predictability. Entropy helps explain why certain processes are irreversible (broken eggs don't spontaneously reassemble), why maintaining order requires energy input, and why information processing has physical limits. Understanding entropy provides insights into efficiency constraints, the arrow of time, and the fundamental trade-offs between order and disorder in natural and engineered systems.