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Filter Paper Chromatography

Supplies:	A large piece of filter paper, or a coffee filter Several water-washable marking pens (black often has an interesting result) A pie-shaped piece of filter paper A small plastic cup with water
Procedure:	Make a number of simple marks with the water-washable markers on the filter paper, in the center one third of the paper. Use a needle or the tip of a pencil to poke a hole in the center of the filter paper. Roll the pie wedge into a wick & insert a few millimeters into the needle hole in the filter paper. Place the filter paper on the plastic cup such that the pie wedge extends below the filter paper and well into the water. Allow the image to "develop" until capillary action has moved the water to wet most of the filter paper.  This may take 15 minutes to one half hour. Remove the filter paper from the water, remove the paper wedge from the filter paper, and set the filter paper on a paper towel to dry.

Notes: 

1. Coffee filter papers may be substituted for laboratory filter paper.
2. You must use water soluble/water washable markers.  The ink from permanent markers will not move with the water.
3. Black pens often separate into an array of interesting colors.
4. Once you remove the filter paper assembly from the water it will not work to put it back in.
5. This experiment is an example of paper chromatography.  The water solvent carries the marker ink along the filter paper as the water is sucked through the paper by capillary action.  Some components of the marking pen pigment move faster on the paper than others, resulting in the mark on the paper separating into its component colors, with sometimes spectacular results.

 

----Contributed by Jackie Stewart, Mark Twain Section