Figure 5.

Experimental support for Fick's law, even down to few-particle gradients. The average flux, 〈J〉, is shown as a function of ΔN, the gradient in the particle number between two neighboring bins. Experimental data are shown in circles, while the solid line represents the fit to the data. The coefficient of determination, R², for the fit is also reported. The error bars shown are the variances due to the different combinations of N₁ and N₂ resulting in the same ΔN. The slope and intercept are in agreement with the expected theoretical values, based on eq 4.