Arizona Science Center: Walking Rainbow

The three primary colors are: red, yellow, and blue. When primary colors mix, they produce what are called secondary colors: orange, green, and purple. All six of these colors make up the rainbow.

Children will investigate how water molecules paper towels to mix substances in two separate cups. The colored water moves up the paper towel by a process called capillary action. Capillary action is the ability of a liquid to flow upward, against gravity, in narrow spaces. This is the same thing that helps water climb from a tree’s roots to its leaves at the top. Paper towels are made from plant fibers called cellulose. In our walking rainbow experiment, the water flows upward through the tiny gaps between the cellulose fibers. The attractive forces between water and cellulose fibers make this possible.

Biology, Botany

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