What are some real life examples of diffusion?
A groundwater contamintant is an example
I was hired by district court almost 9 years ago to evaluate a contamination case. A cheese factory was discharging its untreated wastewater into an empty agricultural field nearby. However, some wastewater was entering subsurface. I measured wastewater (over surface) in terms of pH (lower than 6 based on three different samples), dissolved oxygen (lower than 2.0 mg per Liter), electrical conductivity (higher than 82 mS/cm), and Redox potential (oxidation-reduction potential, which was higher than 125 mV).
In 2011 and In 2012, we were able to get subsurface contamination (see below images) by electrical methods used in geophysics/geophysical engineering. As you can see contamination enlarges, sometimes becomes grift. I estimated that highly contaminated zone enlarged 4.5% in 6 months (based on two dimensional view).
Diffusion occurs (blue areas on the right hand side narrowed between 28th of October, 2011 and 4th of May, 2012).
Thanks Dr. Yunus Levent Ekinci (Bitlis Eren University Assistant Professor, Turkey) (for providing these images).