Related Experiment Video
Updated: Nov 27, 2025

Applications of EEG Neuroimaging Data: Event-related Potentials, Spectral Power, and Multiscale Entropy
Published on: June 27, 2013
Entropy and Time
1Department of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Abstract:
The idea that entropy is associated with the "arrow of time" has its roots in Clausius's statement on the Second Law: "Entropy of the Universe always increases." However, the explicit association of the entropy with time's arrow arises from Eddington. In this article, we start with a brief review of the idea that the "increase in entropy" is somehow associated with the direction in which time increases. Then, we examine three different, but equivalent definitions of entropy. We find that none of these definitions indicate any hint of a relationship between entropy and time. We can, therefore, conclude that entropy is a timeless quantity. We also discuss the reasons as to why some scientists went astray in associating entropy with time's arrow. Finally, we shall discuss Boltzmann's H-Theorem, which is viewed by many as a proof of the Second Law of Thermodynamics.
More Related Videos
11:00Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section
Published on: July 19, 2016
10:02Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection
Published on: February 18, 2014
Related Concept Videos
Entropy
Entropy
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
Entropy and the Second Law of Thermodynamics
The relation between entropy and disorder can be illustrated with the example of the phase change of ice to water. In ice, the molecules are located at specific sites giving a solid state, whereas, in a liquid form, these molecules are much freer to move. The molecular arrangement has therefore become more randomized. Although the change in average...
The Second Law of Thermodynamics
Third Law of Thermodynamics
Second Law of Thermodynamics