Rainbow Paper - Marker Pen Chromatography

Kids try this yourself.
Draw different colour dots along one side of a sheet of paper towel. Make sure to use water based marker pens (not permanent ink).
Then dip the edge into water so that it soaks in. The water will spread up the page, and carry the colour along.
As the colour rises up the page it will separate into different component colours.
The science.
The water is drawn up the page by capillary action. The separation of colours is due to some colours moving easier than others. This is the principle of chromatography.
This video was shot for a primary school science project with my daughter.
The first part is a time-lapse. Then I've used macro photography to zoom into the fibre of the paper to show the clumps of colour.
This video covers:
00:00 - Time-lapse of the colour separation
00:50 - Details
01:00 - Zooming into the image until you can see the paper fibres
01:21 - Macro photographs