Let’s have some fun with colors. You may have heard that the primary pigment colors for painting and art are red, yellow, and blue. So how are there so many other colors in your box of crayons?
The other colors are made from mixing primary colors to get secondary colors, mixing secondary colors with primary colors or other secondary colors, etc. Do you get the picture?
And, have you ever seen water “walk”?
Let’s investigate to see what happens. Gather these inexpensive supplies: three short plastic cups with the top diameter wider than the bottom, blue and yellow food coloring, water, and white napkins.
Place the three cups in a row with the tops about ½ inch (1 cm) apart. Pour water into the first and third cups, making them about half full. Squeeze about six drops of yellow food coloring into the first cup and the same number of drops of blue coloring into the third cup.
Fold a napkin to about 2 inches (5 cm) wide and then bend it in half. Place one end into the first cup with the other end reaching the bottom of the middle cup. Do the same for the last cup, making one end of the napkin reach into the blue coloring and the other into the middle cup. Be sure one end of each napkin is in the colored water and the other end touching the bottom of the middle cup. Don’t let the napkins in the middle cup touch each other.
Watch as the colored water starts climbing the napkins and going down the other side into the middle cup. This will take a little time, of course.
Water travels upward due to capillarity. Capillary action is the ability of liquids to move upward without the aid of external forces. You’ve seen capillary action when a paper towel soaks up water from the cup you knocked over. You’ve observed capillarity, or wicking, when melted wax from the candle travels up the wick and provides the fuel that keeps it burning. When you water Mother’s house plants, capillary action helps pull the water from the roots upward through the stem and into the leaves.
Now, has the colored water from both cups reached the bottom of the middle cup? If it has, add some clear water to this middle cup and watch the lovely color appear, created from the blue and yellow food coloring.
You might enjoy doing this experiment again using red and yellow drops of coloring or red and blue coloring.
I think Mother will be glad for your help in the cleanup afterwards.