The Paramecium Swims Through Honey — Where Viscosity Comes From and Why Fourier and Fick Wrote the Same Line
·7 min read
At 1 atm the mean free path is about 68 nm and the mean speed about 470 m/s. One flux, μ ≃ ρ c̄ ℓ / 3, is the line Fourier and Fick used for heat and mass.