Effusion Definition

Chemistry Glossary Definition of Effusion

This diagram shows effusion (left) and diffusion (right).
This diagram shows effusion (left) and diffusion (right). Effusion occurs through a hole smaller than the mean path of moving particles while diffusion occurs through a hole large enough allow multiple particles to pass at once. Astrang13, Creative Common License
by Anne Marie Helmenstine, Ph.D.
Updated March 07, 2017

Effusion Definition: ​

Effusion is the movement of a gas through a pore or capillary into another gaseous region or into a vacuum.