Monday 8 April 2013

Coffee filter chromatography

My Dad was a chemistry teacher, and when I was little he used to take us into his classroom during the holidays to do some simple science experiments. One of my favourites was coffee filter chromatography, and remembering how much I enjoyed it I decided to have a go with Harry. Of course the science behind it went completely over his head, but he loved seeing 'what's inside felt tip pens' and keeps requesting to do it over and over!

Coffee filter chromatography with children science experiment

It is so quick and easy to do, all you need are some white coffee filters (affiliate link), felt tip pens in a variety of colours and a glass of water. If your child is impatient then I'd recommend having a practice by yourself first, as some pens work better than others. In particular it's generally the darker colours that give the best results. Basically, you are separating out the different components of the ink in the felt tip pen.

Cut the coffee filters into strips as long as you can make them. Using the felt tip pen make a largish blob about halfway down. Then dip one end of the strip into the glass of water and wait for the water to soak up towards the pen mark. As the water reaches the colour it will begin to spread out and hopefully the different inks in the pen will spread out in a nice flared pattern, with the lighter colours at the top. Place it onto some kitchen roll to dry out.

You can experiment with different types of pen and try different types of marks to see which ones give the most interesting results. You could also try using several different coloured pens on the same piece of coffee filter. Here are some of our prettiest papers:

Coffee filter chromatography with children science experiment


  1. Great Idea. I've managed to find white coffee filters yesterday so we will try this. In the past, I have only been able to find brown and the colours don't appear as vibrant as they could. Your Dad sounds like fun!

    1. The white ones will definitely work better, good luck! We had a lot of fun doing science experiments, we dipped candles, developed photos, separated salt from sand - I loved visiting his lab! I wonder how much things have changed in schools now, I hope they still do all the same experiments with bunsen burners and so on.

  2. Your dad sounds cool and this looks like a great experiment.

  3. Love it! Chemistry was my favourite science at school - I'm going to have to try this with my little man! Thanks for sharing another great activity :)


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