or green bulbs are substituted for the clear flashlight
bulbs. A cardboard box creates the darkened area
needed for children to observe the effects of mixing
colored lights. A piece of white paper mounted in the
back of the box provides a colorless surface for the
experiment. Red, blue, green, yellow, cyan, and magenta color
tiles, made by clipping the appropriate colors from
free paint-sample cards, mounting them to note
cards, and printing the name of the color on the card,
are also included in the center. Children can use the
tiles to show the results of mixing the colored lights.
Children can record their observations on documen-
Comments and Questions
to Support Inquiry
• What color of light do you see when you mix the
red and green lights? Does that happen when you
mix red and green paint? Let’s write down that red
and green light make yellow, and later we’ll try mix-
ing red and green paint.
• If you work together, you can combine three col-
ors of light. Let’s see what happens.
• How would you describe the color of light you
made by combining green and blue? That color is
When colors that are emitted directly from a light
source are combined, new colors are produced by an
additive process. This is different from the subtractive
process that is involved when colored pigments, such
as paint or colored water, are combined (see Activity
4.11). Red and green lights combine to produce yel-
low; green and blue lights produce cyan; and red and
blue lights produce magenta. Red, green, and blue
lights produce white when all three are combined.
When mixing colored lights, the primary colors
are red, blue, and green. This is different from
the primary colors for mixing pigments, which
earlier color theory identified as red, blue, and
yellow and are now known to be magenta,
cyan, and yellow.
The mathematics content in this center involves
comparing the results of mixing two primary colors of
light, which produce a secondary color, with combin-
ing three colors of light, which produces white.
ST E M lE aR n I ng c E n T E R S