<jupyter_start><jupyter_text>`mean_free_path`The mean free path is the average distance of a molecule between collisions with other molecules present in the medium. We use the kinetic theory of gases to calculate the mean free path in an ideal gas as$$\lambda = \frac{2 \mu / p}{(8 \, \mathrm{MW} / (\pi R T))^{1/2}} $$where $\lambda$ is the mean free path, $\mu$ is the dynamic viscosity, $p$ is the pressure, $\mathrm{MW}$ is the molecular weight, $R$ is the gas constant, $T$ is the temperature. As noted above, the user can provide an explicit value for $\mu$ or it can be calculated using the above formula (that is, the user can provide the inputs to the above formula for $\mu$). At default conditions, $\lambda$ is about 66.5 nm.<jupyter_code>from particula.environment import Environment
print("mean free path is ", Environment().mean_free_path()) # will produce approx 66.5 nm
from particula.util import mean_free_path
help(mean_free_path)<jupyter_output><empty_output>
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