Fast Video of Capillary formation in a very simple Plate-Water-Plate system

We put two micro glass slides (75 mm x 25 mm x 1.2 mm) together and dipped in a coloured (KMnO4) water solution. The liquid rises in the gap (determined by the plates' roughness and flatness) between the two plates. Once completely filled, the plates were taken out and placed vertically (as shown in the video). This system was then allowed to evaporate from all the four open sides.We see the formation of a dominant capillary even in such a simple system. In soils, the formation of a dominant capillary is augmented by several particles. The configuration we used can be considered as a model to understand the formation of films in (wet) soils undergoing evaporation.