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

Distribution of Molecular Speeds01:27

Distribution of Molecular Speeds

5.2K
The motion of molecules in a gas is random in magnitude and direction for individual molecules, but a gas of many molecules has a predictable distribution of molecular speeds. This predictable distribution of molecular speeds is known as the Maxwell-Boltzmann distribution. The distribution of molecular speeds in liquids is comparable to that of gases but not identical and can help to understand the phenomenon of the boiling and vapor pressure of a liquid. Consider that a molecule requires a...
5.2K
Maxwell-Boltzmann Distribution: Problem Solving01:20

Maxwell-Boltzmann Distribution: Problem Solving

2.7K
Individual molecules in a gas move in random directions, but a gas containing numerous molecules has a predictable distribution of molecular speeds, which is known as the Maxwell-Boltzmann distribution, f(v).
This distribution function f(v) is defined by saying that the expected number N (v1,v2) of particles with speeds between v1 and v2 is given by
2.7K
Steady, Laminar Flow in Circular Tubes01:23

Steady, Laminar Flow in Circular Tubes

844
Hagen-Poiseuille flow describes a viscous fluid's steady, incompressible flow through a cylindrical tube with a constant radius R. This flow profile is often applied to understand fluid transport in narrow channels, such as capillaries. It serves as a foundational example of laminar flow. In this model, cylindrical coordinates (r,θ,z) are used to describe the radial (r), angular (θ), and axial (z) dimensions within the tube. For Hagen-Poiseuille flow, the velocity profile is purely axial,...
844
Kinetic Theory of an Ideal Gas01:12

Kinetic Theory of an Ideal Gas

4.5K
A mole is defined as the amount of any substance that contains as many molecules as there are atoms in exactly 12 grams of carbon-12. An Italian scientist Amedeo Avogadro (1776–1856) formed the  hypothesis that equal volumes of gas at equal pressure and temperature contain equal numbers of molecules, independent of the type of gas. Later, the hypothesis was developed to form the SI unit for measuring the amount of any substance.
The number of molecules in one mole is called...
4.5K
Mean free path and Mean free time01:22

Mean free path and Mean free time

4.7K
Consider the gas molecules in a cylinder. They move in a random motion as they collide with each other and change speed and direction. The average of all the path lengths between collisions is known as the "mean free path."
4.7K
Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion03:48

Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion

30.9K
Although gaseous molecules travel at tremendous speeds (hundreds of meters per second), they collide with other gaseous molecules and travel in many different directions before reaching the desired target. At room temperature, a gaseous molecule will experience billions of collisions per second. The mean free path is the average distance a molecule travels between collisions. The mean free path increases with decreasing pressure; in general, the mean free path for a gaseous molecule will be...
30.9K

You might also read

Related Articles

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

Sort by
Same author

Macropinocytic Uptake and pH-Responsive Endolysosomal Processing Drive Sustained Chemotherapeutic Efficacy of High-Load Core@Shell Nanocarriers in Colorectal Cancer.

Small science·2026
Same author

Observing the Glass and Jamming Transitions of Dense Granular Material in Microgravity.

Physical review letters·2025
Same author

Training convolutional neural networks with the Forward-Forward Algorithm.

Scientific reports·2025
Same author

Dynamics in vibrofluidized beds: A diffusing wave spectroscopy study.

Physical review. E·2025
Same author

Rheological Regimes in Agitated Granular Media under Shear.

Physical review letters·2025
Same author

Impact of Femoral and Tibial Torsion on Patellofemoral Loading in Individuals With Patellofemoral Instability.

Journal of orthopaedic research : official publication of the Orthopaedic Research Society·2025

Related Experiment Video

Updated: Dec 19, 2025

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
11:03

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

Published on: December 4, 2017

8.9K

Velocity Distribution of a Homogeneously Cooling Granular Gas.

Peidong Yu1,2, Matthias Schröter1, Matthias Sperl1,2

  • 1Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Cologne, Germany.

Physical Review Letters
|June 6, 2020
PubMed
Summary

Granular gases, unlike molecular gases, need continuous driving due to inelastic collisions. This study experimentally confirms the predicted exponential decay in granular gas velocity distributions after driving stops.

More Related Videos

The Diffusion of Passive Tracers in Laminar Shear Flow
08:01

The Diffusion of Passive Tracers in Laminar Shear Flow

Published on: May 1, 2018

8.9K
Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
11:51

Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions

Published on: February 22, 2018

9.0K

Related Experiment Videos

Last Updated: Dec 19, 2025

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
11:03

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids

Published on: December 4, 2017

8.9K
The Diffusion of Passive Tracers in Laminar Shear Flow
08:01

The Diffusion of Passive Tracers in Laminar Shear Flow

Published on: May 1, 2018

8.9K
Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
11:51

Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions

Published on: February 22, 2018

9.0K

Area of Science:

  • Physics
  • Soft Matter Physics
  • Statistical Mechanics

Background:

  • Granular gases differ from molecular gases due to inelastic collisions, necessitating continuous energy input to maintain kinetic energy.
  • The kinetic theory of granular gases predicts a decay in average particle velocity and a specific stationary velocity distribution after driving ceases.
  • Previous numerical simulations supported these theoretical predictions, but experimental validation was lacking.

Purpose of the Study:

  • To experimentally confirm the theoretically predicted behavior of granular gases after the cessation of external driving.
  • To validate the kinetic theory's prediction of velocity distribution changes in granular gases.

Main Methods:

  • Conducted a microgravity experiment using spheres as granular gas particles.
  • Employed magnetic fields for spatially homogeneous excitation of the granular system.
  • Analyzed particle velocity distributions to observe changes after driving was shut off.

Main Results:

  • Observed a decay in the average particle velocity as predicted by kinetic theory.
  • Experimentally confirmed the theoretically predicted exponential decay in the high-velocity tails of the particle velocity distribution.
  • Provided the first experimental validation of this fundamental theoretical result for granular gases.

Conclusions:

  • The study successfully provides experimental evidence supporting key predictions of the kinetic theory of granular gases.
  • The findings confirm the unique behavior of granular gases, particularly the nature of their velocity distribution tails.
  • This research bridges the gap between theoretical predictions and experimental observations in granular gas dynamics.