Entropy is a fundamental concept in physics and thermodynamics, representing a measure of the disorder or randomness within an isolated physical system. The second law of thermodynamics dictates that the total entropy of any isolated system can only increase over time, meaning that systems naturally tend towards states of greater disorder and energy dissipation. This principle governs how heat flows, how chemical reactions proceed, and how energy disperses into a surrounding environment. While entropy generally increases in the universe, local decreases in entropy (such as the formation of life) are possible only by an even greater overall increase in entropy elsewhere, illustrating the constant trade-off between order and universal disorder.