Paper Towel Experiment: Marker Ink Chromatography

This paper towel experiment shows the different components of water based marker inks using nothing more than a few readily available household items. This experiment will help your child to understand the complex nature of colour.

Materials Needed: You will need the following:

* set of water based markers
* paper towel
* scissors
* a drinking glass
* pencil
* sticky tape

Procedure:

Step 1: Cut a strip from the paper towel that is 3cm wide at the base and slightly longer than the drinking glass is tall.

Step 2: Put spots of 4 or 5 different marker colours 1cm from the base of the paper strip. Write the names of the colours underneath them with the pencil.

Step 3: Secure the paper strip to the pencil with sticky tape.

Step 4: Place about half a centimetre of water in the bottom of the drinking glass.

Step 5: Lay the pencil across the top of the glass so that the bottom of the paper strip is only just in the water. Make sure the ink spots are NOT submerged.

Step 6: Wait and watch; this experiment is complete within ten minutes and the process is just as interesting as the end result.

What is Happening?

MOst marker inks are a mixture of two or more different pigments. Since each pigment is a different chemical, they each have different abilities to absorb in to the water as well as different abilities to stick to the paper and resist going into solution.

This affects the speed with which they move up the paper strip, and so the different colours are separated. Darker colours usually contain more pigments which is why black and brown give such good results in this paper towel experiment.

Future Knowledge:

The concepts behind chromatography are important in senior high school Chemistry. Having a background knowledge of this simple experiment will make learning these advanced concepts far easier.