Paper chromatography

Are the colours of the coloured felt-tip pens in your pencil case pure colours?
From art classes you know that many colours can be obtained by mixing other colours.
Can mixtures of different colours be separated again? Is Black a single pigment or can black also be made up of different dyes? To answer these questions, you should perform the following experiment.

1.     Make a hole with a pencil in the middle of the round filter paper.

2.     Draw a circle around this hole, half with a soft pencil and half with the black felt-tip pen.

3.     Roll up a piece of paper towel into a wick and push it through the hole in the round filter.

(more see below)


4.     Fill the ampoule with water and push it in the stand.

5.     Place the wick, together with the filter paper, on the ampoule so that the wick dips into the water. The filter paper itself does not come into direct contact with the water rising up the wick.                                                                                                                    6.     When no further changes are seen to occur, disconnect the filter paper from the wick and let it dry. What do you see?

7.   Repeat steps 1 - 6 at home with a brown felt-tip pen.

First publication: 2003                                                                         Last modification: 12.06.2014