The final part of the Year 5 topic ‘Dissolving and Separating’ is ‘Chromatography’. Ms Knott’s Year 5 class were given five different black pens and asked to investigate which pen matched the Chromatogram Ms Knott had made earlier. Each group worked independently and everyone got the answer right – it was pen number 2.

Chromatography is a fun and easy practical to do at home with your children. All you need is filter paper, some pens (black is best as they contain different coloured inks), a cup, a paperclip and water. Cut the filter paper into strips, draw a pencil line 1cm from the bottom and put a large dot of ink on the line. Put just the very bottom of the paper into the cup of water and fix it in place for 5 minutes with a paperclip. Watch the water be absorbed up the paper as the inks separate at the same time.

Set your kids a similar challenge at home, make a quick chromatogram from a pen in your house and challenge the kids to do chromatography on a selection of pens to figure out which one you used –  the Prize could be the wifi password for that day!

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