<P> The mean free path is used in the design of chemical apparatus, e.g., systems for distillation . The sizes of atoms and molecules can be estimated from their mean free path . MFP can be used to estimate the resistivity of a material from the mean free path of its electrons . </P> <P> In aerodynamics, the mean free path has the same order of magnitude as the shockwave thickness at Mach numbers greater than one . </P> <Table> <Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2017) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section does not cite any sources . Please help improve this section by adding citations to reliable sources . Unsourced material may be challenged and removed . (March 2017) (Learn how and when to remove this template message) </Td> </Tr>

The mean free path is the average distance travelled by a molecule