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Investigating inks


This week I'd like you to carry out some experiments.


Felt-tip pen ink
Ink is usually made from a mixture of colours.
If you draw a felt-tip line(make sure it's washable!) on a piece of kitchen roll, when water soaks up the paper and touches the ink, the ink dissolves, spreading out and separating into different colours. This is called chromatography.


Try out the following experiments and record your observations and conclusions on the worksheet provided. 

You will need: coffee filter paper, kitchen roll, paper, black, blue and red felt-tip pens, ball-point pen, jar/bowl, water.

If you don't have any filter paper, miss out experiment 1 and substitute filter paper with kitchen paper.

There is an explanation clip and two extra experiments below, plus the explanations for your experiments at the bottom of the page.

Have fun and send me some pictures on dojo. Mrs Battye laugh




Experiment explanations (answers)



Experiment 1- Many colours

The colours and patterns made by different inks will vary, depending on what they contain. Some colours dissolve more easily in the water and travel further as they spread through the paper.


Experiment 2 - High Line

The water takes longer to reach the ink, but the ink dissolves and separates in a similar way.


Experiment 3 - Kitchen paper
The ink spreads more on kitchen paper because it is more absorbent. The more absorbent the paper, the faster the water spreads and the faster the ink dissolves and separates.


Experiment 4 - Ordinary paper (printer paper)

The ink spreads less well on printer paper than filter paper because it is less absorbent.


Experiment 5 - Ballpoint pen 

Ballpoint pens contain waterproof ink. This kind of ink won't separate because it doesn't dissolve in water.


Experiment 6 - Middle Spot

The colours separate and spread out in a circle as the water soaks through the paper in every direction.