Have students fill clear jars up to the top with water. They should put them on a window sill in direct sunlight, sticking over the ledge just a slight bit. Tape two or three pieces of white paper together onto the floor in front of the jars. When the sun shines, a rainbow will be reflected onto the paper, teaching the children how light influences rainbows. Draw lines or trace where the rainbows fall on the paper and have children color them in.
Take the children outside in the schoolyard if there is a hose, or assign this project as homework with their parents. You must do this project when the sun is shining. Stand with your back facing the sun. Let one of the students or a few of the students hold the hose and spray it on the mist option. See which student finds the rainbow the quickest.
Teach children the colors of the rainbow and explain why rainbows have so many different colors in them. Cut equal lengths of yarn for each color of the rainbow. Allow the students to dip the strands of yarn in glue and then paste them onto a light blue piece of paper. Distribute cotton balls and instruct the students to place some cotton balls at the end of the rainbow to form a cloud.
Use food dye to make ice cubes that are red, yellow and blue. Each child should have two cubes of each color. Put one yellow and one red cube in a plastic bag, and have the child rub his hands over the bag and blow on it. The color will change to orange. Have them do this activity to create purple and green as well. When they are done, explain that they have made the colors of the rainbow.