Talk about white light and rainbows. White light is made up of many different colors, but our eyes blend all the colors together, so the light appears white to us. When the light passes through the prism or water, it is bent and our eyes then see the individual colors. When light bends it is called refraction . Help the students understand the difference between reflection and refraction.
Reflection is when light bounces off an object.
Refraction is when light passes through the object but is bent in the process. Just as the prism bent the light and created a rainbow on the wall, the raindrops bend the sunlight and create a rainbow in the sky. Present the color disk. Use the hand drill to spin the disk. Ask students to predict what will occur as the disk is spun faster.