Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Entropy01:18

Entropy

2.6K
The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the 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...
2.6K
Entropy and the Second Law of Thermodynamics01:20

Entropy and the Second Law of Thermodynamics

2.8K
The second law of thermodynamics can be stated quantitatively using the concept of entropy. Entropy is the measure of disorder of the system.
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...
2.8K
Variance01:15

Variance

9.7K
 The deviations show how spread out the data are about the mean. A positive deviation occurs when the data value exceeds the mean, whereas a negative deviation occurs when the data value is less than the mean. If the deviations are added, the sum is always zero. So one cannot simply add the deviations to get the data spread. By squaring the deviations, the numbers are made positive; thus, their sum will also be positive.
The standard deviation measures the spread in the same units as the...
9.7K
The Second Law of Thermodynamics01:14

The Second Law of Thermodynamics

5.3K
In the quest to identify a property that may reliably predict the spontaneity of a process, a promising candidate has been identified: entropy. Scientists refer to the measure of randomness or disorder within a system as entropy. High entropy means high disorder and low energy. To better understand entropy, think of a student’s bedroom. If no energy or work were put into it, the room would quickly become messy. It would exist in a very disordered state, one of high entropy. Energy must be...
5.3K
Second Law of Thermodynamics02:49

Second Law of Thermodynamics

23.8K
In the quest to identify a property that may reliably predict the spontaneity of a process, a promising candidate has been identified: entropy. Processes that involve an increase in entropy of the system (ΔS > 0) are very often spontaneous; however, examples to the contrary are plentiful. By expanding consideration of entropy changes to include the surroundings, a significant conclusion regarding the relation between this property and spontaneity may be reached. In thermodynamic...
23.8K
Entropy Change in Reversible Processes01:10

Entropy Change in Reversible Processes

2.5K
In the Carnot engine, which achieves the maximum efficiency between two reservoirs of fixed temperatures, the total change in entropy is zero. The observation can be generalized by considering any reversible cyclic process consisting of many Carnot cycles. Thus, it can be stated that the total entropy change of any ideal reversible cycle is zero.
The statement can be further generalized to prove that entropy is a state function. Take a cyclic process between any two points on a p-V diagram.
2.5K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Computational Microscopy Reveals Compound-Specific Flickering Phenotypes of Red Blood Cells Under Flavonoid Exposure.

Membranes·2026
Same author

Determining the Effective DNA Charge Density from Nanopore Translocation Dynamics.

Nano letters·2026
Same author

Stochastic motility energetics reveals cooperative bacterial swarming in optical tweezers.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Antecedent hypoglycaemia impairs glucagon secretion by enhancing somatostatin-mediated negative feedback control.

Nature metabolism·2026
Same author

Active Force Dynamics in Red Blood Cells Under Non-Invasive Optical Tweezers.

Advanced science (Weinheim, Baden-Wurttemberg, Germany)·2025
Same author

Extensile Active Hydrogels Driven by Living FtsZ Polymers.

Small (Weinheim an der Bergstrasse, Germany)·2025
Same journal

A native sulfur deposit in Gale crater, Mars.

Science (New York, N.Y.)·2026
Same journal

Coordinated demise of harmful algal blooms.

Science (New York, N.Y.)·2026
Same journal

Genetic effects put into context.

Science (New York, N.Y.)·2026
Same journal

Bacteria share proteins to survive antibiotics.

Science (New York, N.Y.)·2026
Same journal

Impacts shaped Earth's first continents.

Science (New York, N.Y.)·2026
Same journal

Erratum for the Report "Covalently bonded single-molecule junctions with stable and reversible photoswitched conductivity" by C. Jia <i>et al</i>.

Science (New York, N.Y.)·2026
See all related articles

Related Experiment Video

Updated: Jul 2, 2025

Applications of EEG Neuroimaging Data: Event-related Potentials, Spectral Power, and Multiscale Entropy
11:15

Applications of EEG Neuroimaging Data: Event-related Potentials, Spectral Power, and Multiscale Entropy

Published on: June 27, 2013

33.7K

Variance sum rule for entropy production.

I Di Terlizzi1,2, M Gironella3,4, D Herraez-Aguilar5

  • 1Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany.

Science (New York, N.Y.)
|February 29, 2024
PubMed
Summary
This summary is machine-generated.

Researchers developed a new method to measure nanoscale entropy production using a variance sum rule. This technique quantifies irreversibility and energy dissipation in nonequilibrium systems, applicable to active matter and biological cells.

More Related Videos

Decomposing the Variance in Reading Comprehension to Reveal the Unique and Common Effects of Language and Decoding
06:33

Decomposing the Variance in Reading Comprehension to Reveal the Unique and Common Effects of Language and Decoding

Published on: October 11, 2018

6.8K
Quantification of Information Encoded by Gene Expression Levels During Lifespan Modulation Under Broad-range Dietary Restriction in C. elegans
09:23

Quantification of Information Encoded by Gene Expression Levels During Lifespan Modulation Under Broad-range Dietary Restriction in C. elegans

Published on: August 16, 2017

8.1K

Related Experiment Videos

Last Updated: Jul 2, 2025

Applications of EEG Neuroimaging Data: Event-related Potentials, Spectral Power, and Multiscale Entropy
11:15

Applications of EEG Neuroimaging Data: Event-related Potentials, Spectral Power, and Multiscale Entropy

Published on: June 27, 2013

33.7K
Decomposing the Variance in Reading Comprehension to Reveal the Unique and Common Effects of Language and Decoding
06:33

Decomposing the Variance in Reading Comprehension to Reveal the Unique and Common Effects of Language and Decoding

Published on: October 11, 2018

6.8K
Quantification of Information Encoded by Gene Expression Levels During Lifespan Modulation Under Broad-range Dietary Restriction in C. elegans
09:23

Quantification of Information Encoded by Gene Expression Levels During Lifespan Modulation Under Broad-range Dietary Restriction in C. elegans

Published on: August 16, 2017

8.1K

Area of Science:

  • Non-equilibrium physics
  • Statistical mechanics
  • Soft matter physics
  • Biophysics

Background:

  • Entropy production quantifies irreversibility and dissipation in physics, crucial for understanding energy transduction.
  • Measuring entropy production at the nanoscale is a significant challenge in nonequilibrium systems.
  • Existing methods often lack the precision or applicability for complex nanoscale phenomena.

Purpose of the Study:

  • To introduce a novel Variance Sum Rule (VSR) for measuring the rate of entropy production (σ) in nonequilibrium steady states.
  • To demonstrate the VSR's applicability to systems with directly measurable forces and complex biological systems.
  • To provide a new tool for quantifying irreversibility and dissipation at the nanoscale.

Main Methods:

  • Development of a Variance Sum Rule (VSR) relating displacement and force variances.
  • Application of VSR to an active Brownian particle in an optical trap.
  • Experimental validation using flickering measurements in human red blood cells.

Main Results:

  • The VSR successfully measures entropy production rate (σ) in nonequilibrium steady states.
  • Spatially heterogeneous entropy production with a finite correlation length was observed in red blood cells.
  • Average entropy production values obtained via VSR agree with independent calorimetry measurements.

Conclusions:

  • The Variance Sum Rule (VSR) offers a practical method for measuring nanoscale entropy production.
  • VSR is applicable to diverse systems, including active matter and biological cells.
  • This work enables the derivation of entropy production using force spectroscopy and time-resolved imaging.