# What Is Entropy and How Does It Work? Discover one of the most misunderstood concepts in science: entropy. - **Source:** [Science Latest](https://brifing.si/source/ebc20f22-8d1a-4ae4-ba4c-efcd0853ba19) - **Published:** 2026-07-24 - **Topic:** [Data & AI](https://brifing.si/c/data-ai) - **Original article:** - **On Brifing:** https://brifing.si/s/eee1a1df-3d00-4ca2-b3e2-4e9dcdd25004 ## Introduction to Entropy Entropy is often defined as 'disorder,' but this is misleading. It actually refers to the number of ways a system's parts can be arranged without changing its overall state. For example, air molecules in a box can exist in trillions of microstates, all corresponding to the same macro pressure. ## Micro and Macro Worlds Entropy bridges the invisible atomic world and the measurable macro world. It explains how energy distribution is based on probabilities. For instance, the likelihood of rolling a specific number with dice is directly related to entropy. ## Probability and Entropy Entropy is tied to the probability of a system being in a certain state. For example, rolling three dice to get a total of 10 is more likely than rolling an 18 because more microstates lead to that outcome. This is the foundation of entropy. ## Second Law of Thermodynamics The second law states that entropy in a closed system always increases over time. This means energy will distribute toward more probable states. For example, a hot copper ball in cold water will transfer energy until equilibrium is reached. ## Energy Distribution Entropy describes how energy disperses. While a hot object typically transfers energy to a colder one, the reverse is theoretically possible—but extremely unlikely because high-entropy states are more probable. ## Quantum and Entropy Quantum mechanics dictates that atoms have discrete energy levels. In a three-atom system with 10 units of energy, there are 27 possible microstates. Entropy determines the likelihood of these states occurring. ## Real-World Example Entropy appears in everyday life, but not in the way many think. A messy room isn't explained by entropy, as it doesn't involve energy distribution. Entropy refers to molecular-level energy dispersal. ## The Significance of Entropy Entropy is crucial for understanding the universe. It explains why energy flows in certain directions, why systems reach equilibrium, and how probabilities shape the physical world. It's a foundational principle in science and engineering. ## Sources covering this story - https://www.wired.com/story/what-is-entropy-really/ — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._