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Color Un-Mixing

What colors are really in your markers?

Do it!

  • Cut a long strip from a coffee filter or paper towel about an inch wide.
  • Put a dot of color using a washable marker an inch or two from the bottom of a coffee filter strip.
  • Put about an inch of water in the bottom of a jar or cup.
  • Hang the strip in the jar so just the bottom (but not the color!) is in the water.
  • Watch as the water climbs up the filter and spreads out the colors in the marker!

What happens?

The water moves up the filter strips using capillary action.  The water sticks to the paper towel or coffee filter more than it sticks to itself and moves up the fibers in the strip.

The colors in the marker ink move along with the water but at different rates.  Some colors move faster than others and separate on the filter.

Which markers have lots of different colors? Which have just one or two?

What else can you use?  Try candies, lipsticks and even leaves!  You might need to use rubbing alcohol instead of water for some of these – try it to find out!

More on this activity from Scientific American