Classroom Activity: Making a Rainbow . ... When white light from the Sun or a light bulb passes through a prism, the light splits into its component wavelengths. ... Red, blue, green colored filters - if possible, cut 1x4-inch pieces of the filters for each student . ... Many students have the misconception that filters somehow dye the light a certain color. ... Younger students can draw the rainbow and make up a mnemonic for remembering the order of the colors (such as, ROY G. BIV). ...