Create a rainbow with water

29 09 2010

Do you remember when we learned about capillary action and how it causes water to go up a paper towel soaking into its pores? This new experiment uses capillary action to separate color pigment.

Cut a 2 inch by 5 inch strip from a paper towel or coffee filter. Draw a line across the strip 2 inches from the bottom using a washable black marker. Fill up the cup less thank an inch. Place the paper strip into the cup

Watch as the water travels up the paper towel carrying the ink from the marker. Different colors of pigment do not move at the same speed, allowing us to separate the colors.

This process is called color chromatography, and it shows the different colors that were used to make the black ink.  You can experiment using  markers that are a different type or color.


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