Preschool kids can learn about the color spectrum with this simple experiment. You'll need at least ten strips of white card stock or poster board, three disposable plastic cups, water and food coloring in red, blue and yellow. Fill the cups halfway with water. Dye the water in each cup a different primary color using the food coloring. Dip each strip into one of the colors, and then dip it into a different color. Observe what happens to the colors when you mix them.
Another color spectrum experiment for young primary school students is to have them create their own color wheels. This experiment requires red, blue and yellow transparent plastic sheets, a bright flashlight and a piece of white poster board. Cut out pieces of the colored plastic so they fit over the flashlight lens. Shine each color, in turn, onto the white poster board. Then combine the colors to see what new colors they form. Demonstrate how red and blue make purple, blue and yellow make green, and red and yellow make orange. Students can experiment to make their own colors; for example, combining all three colors will make brown.
A prism separates visible white light into the separate colors of the rainbow. Creating a prism is a useful learning tool for children learning about the color spectrum. To build a prism, you will need a clear drinking glass, a flashlight and some white poster board. Fill the glass half-full with water and set it in the middle of the poster board. Shine the flashlight through the glass and adjust the angle of the light until little rainbows appear on the poster board. You can also use sunlight instead of a flashlight by doing this project outdoors or by a window.
Building a kaleidoscope is an effective way for grade-school kids to play with the colors of the spectrum. For this project, you will need three small mirrors of the same dimension, waxed paper, glue, scissors, colored beads and paper. Glue the mirrors together in a triangular shape with the mirror sides facing inward. Cut a piece of wax paper in the same triangle shape and glue it to one end of the mirror tube. Place enough colored beads in the tube to cover the waxed paper bottom, then close off the tube by covering the other end with a piece of paper and gluing it in place. Poke a small hole in the paper to look through. Give the kaleidoscope a shake, hold it to the light and rotate it as you look inside. The mirrors will reflect the colors of the beads as they move in the kaleidoscope.