How Many Colours?

This investigation is all about chromatography.  Chromatography is a way of separating out a mixture of chemicals.

We are going to separate the chemical colours which make up the ink inside your pens. 

You will need:

Kitchen roll

Scissors

Coloured pens (felt tipped pens work best, a biro or ballpoint pen will not work)

A plate, shallow bowl or tray

Water

Make a prediction. 

Which pen do you think will be made up of the most colours? 

What colours do you think they will be?

Which pen do you think will be made up of the least colours?

What colours will they be?

What happens as the water goes past the coloured dot on your kitchen roll?

Which pen was made up of the most colours?

Which pen was made up of the least colours?

Were you surprised by any of the colour combinations?