Chromatography card
Now it's a star. What will change when you add the water?
What you need
- coffee filter paper
- water soluble marker pens in various colours
- water
- cardboard
- glue
What to do
- Cut the filter paper into a fun shape (like a star).
- Use the marker pens to draw 8-12 coloured dots on the filter paper, making sure the ink is applied quite heavily.
- Dip a finger in the water and carefully place a single drop of water on each coloured dot. Watch the colour spread out from each dot as the paper absorbs the water and notice which colours are mixtures of more than one colour.
- When you are happy with the pattern, leave the paper to dry completely.
- Make a folded card with the cardboard and glue the filter paper on the front of the card.
What's happening?
Chromatography is a method of separating the parts of a mixture. The colour of each marker pen is formed by the mixture of one or more different colour pigments. As the water soaks through the filter paper it carries the pigments with it. Some pigments are carried along the paper faster than others depending on how well they dissolve in water and how much they are attracted to the paper.
