1.)Begin the lesson by having students share their favorite part of a rain shower. After students have shared, make reference to rainbows. Let students share what they know about rainbows. Record their answers on the board.
2.)Share with the students that the sun's tremendous heat causes it to give off light. Explain that sunlight reaches us from 93 million miles away. Also explain that the sun's light travels by rays at very high speeds.
3.)Divide the class into four groups. Have the groups of students conduct the following experiment to demonstrate how the sun's rays create rainbows (use the experiment materials stated earlier).
Place about an inch of water into the baking pan. Set the water where sunlight shines directly on it. Lean the mirror against one edge of the pan. Direct the mirror's reflection onto a white ceiling, wall, or the sheet of paper. Have students observe what happens.
4.)Ask students to hypothesize what causes the rays of light to reflect from the mirror to the bend. (water)
Lead them to formalize, "when the light rays bend, each color in the ray bends at a different angle to produce the rainbow."
5.)Have students observe the different colors and name all of the different colors that they see. Discuss with students when they mostly likely see rainbows. Have the students draw pictures to demonstrate how the sun's rays shine down through the rain to create a rainbow.
6.)Let students share their pictures with the others in the class. Note how each student's picture is different. Explain to students that the sun's rays contain all the colors that they saw in the experiment.
7.)Have students work in pairs to visit websites to learn more about rainbows. Have the students record 3 new facts they learn about rainbows.
(How Rainbows Work
)This site explains how rainbows work.
)This site answers different questions about rainbows. It also shows diagrams illustrating how rainbows are formed.
10.)Once students have found the new facts, have them experiment with creating rainbows on this website.
)This site allows students to explore with light.
11.)After students navigate the different websites, have them write a letter to a friend in another class explaining what they learned about rainbows. Instruct the class to include how the rainbow is formed and how the sun plays a major role in creating the rainbow. Let students illustrate the letters. Once the teacher has graded the letters let the students hand deliver the letters.