Fill 2 cups with water, add blue dye to one cup and yellow dye to the other.  Put an empty cup in between them.  Roll 2 paper towels. Place the end of one towel into the blue dye and one end of the other towel in the yellow dye.  Bend both the towels and put the loose ends into the empty cup and watch the magic happen.  As the colored water is absorbed in the towel it makes its way up and then into the empty cup.  The blue and yellow food dyes combine making green water. via