Discover the hidden colours in ink.
Make beautiful pictures called chromatograms, that show the hidden colours in inks.
ExpeRiment with different pens to see what colour dyes are in their inks.
Learn about the scientific technique of chromatography and how it can be used to solve mysteries.
Some felt-tip pens – make sure they’re not permanent ink markers. Washable ones work best
Some sheets of paper kitchen towel
A tall glass Salt (optional)
For extra activity: two or more pens with different black inks. You can check the black inks are different by making chromatograms of them.
Fiona and her daughters Samantha and Emma explore the beautiful science of chromatography. In this fun experiment to do at home, they reveal the hidden colours inside felt tip pens. As water is drawn up through the kitchen roll, it drags up the colours that make up the felt tip ink. Fiona and her daughters learn that although two inks may look the same, they may be made of different balances of colours. Using their newly learnt skills, Samantha and Emma solve a felt tip mystery, identifying which pens were used to write which letters.