Concepts

Entropy

Citation Formats

General Reference

Science Atlas. "Entropy." Accessed August 30, 2026. https://science.interactiveatlas.org/concepts/entropy.

APA Style

Science Atlas. (n.d.). Entropy. Retrieved August 30, 2026, from https://science.interactiveatlas.org/concepts/entropy

BibTeX

@misc{scienceatlas-entropy,
  author = {Science Atlas},
  title = {Entropy},
  year = {2026},
  url = {https://science.interactiveatlas.org/concepts/entropy},
  note = {Accessed August 30, 2026}
}

Entropy is the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work, and so also a measure of the disorder, or randomness, of a system. The entropy of an isolated system never decreases, which is the physical content of the second law of thermodynamics. Ludwig Boltzmann later gave entropy a statistical meaning, relating it to the number of microscopic arrangements consistent with a system's observable state.

Facts

Proposed Year

1865 1

Proposed By

Rudolf Clausius, who introduced the term in 1865 for the thermodynamic quantity; Ludwig Boltzmann gave it a statistical formulation in the 1870s, relating entropy to the number of microscopic arrangements of a system. 1

Cross-Tradition Connections

Belongs To

Thermodynamics

Source Entropy (Britannica)

Proposed By

Ludwig Boltzmann

Boltzmann's specific contribution is the statistical formulation of entropy (the Boltzmann entropy formula), distinct from Clausius's original 1865 thermodynamic definition of the term.

Source Ludwig Boltzmann (Britannica)

Rudolf Clausius

Source Rudolf Clausius (Britannica)