Simulation of 1-D Diffusion: How it works

Description| How it works

For a slowly diffusing liquid, the liquid column can be assumed to be semi-infinite. The concentration of dye in the column is given by:

c = c(max) x ERF(z / 2 * SQRT(D * t)), where

c is the dye concentration at time t at distance z from the top, c(max) is the concentration of the dye at saturation and ERF() is the error function.

The cells containing this formula are narrowed to 1 pixel high and a 2 colour scale conditional formatting is applied to the cells to show the dye moving up the liquid column.


Excel 2007 and later support more powerful conditional formatting features compared to the earlier versions. They also support a larger number of colours. The fine distinction of colours is not achievable using native Excel 2003 functionality..