These are a great way to teach about light, color, and rainbows. Just look at a light through these Rainbow Viewers and you are treated to a burst of colors. The secret lies in a special diffraction grating which separates the colors of the light into a spectrum of colors. Experiment by looking at different colored lights and different types of lightbulbs. Perfect for looking at holiday lights or fireworks. Made of durable cardboard, each Rainbow Viewer measures 4.3 cm (1.7") diameter. For ages 5+.