Cut out a circular hole in the center of a square piece of cardboard. Place a flask filled with water at level with and behind the hole in the cardboard. Place this apparatus in direct sunlight so rays of sunshine enter through the hole in the cardboard onto the flask of water. You should see a dim rainbow on the cardboard.
Shine a projector light onto a prism. Move the prism around until you can see a rainbow of colors on the wall. Look at the shape and order of the colors as you move the prism.
Turn on a sprinkler in your garden or lawn on a sunny day. Stand so that the sunshine is falling on your back and you are viewing the water from the sprinkler. View the rainbow in the water spraying from the sprinkler.
Add a few drops of universal indicator into a graduated container half-filled with hydrochloric acid. Pour in a solution of saturated sodium carbonate. Watch as a rainbow of colors forms in the container due to the variation of acid-base content.