• During the rainbow investigation, observe how students decide what questions to ask.
• Monitor student responses during class discussions.
• Monitor students as they number the steps in conducting an investigation using the scientific method and completing the rainbow investigation worksheet.

Begin this lesson by showing students a picture of a rainbow (S-K2-13-3_Rainbow Pictures.doc). Allow students time to view the picture. Ask students if they can think of questions to ask about this picture. Students may have several questions about the picture, but listen for the questions, such as “How did that rainbow get there?” and “What made that rainbow?”

Once students have asked the question or you have provided the question, restate a question: “How did that rainbow get there? or What made that rainbow? Let’s look at our steps to see how we can answer this question.” Review the steps and then say: “We need to conduct an investigation, as a scientist would, to try to answer this question.”

Let’s Investigate Rainbows

Make sure that you are in a dark room with a white ceiling. Gather students so they can all see the demonstration. Fill a glass container or measuring cup 2/3 full of water. Hold the container of water in one hand. Take the flashlight in the other hand and turn it on. Shine the flashlight on the container of water. Students should see a rainbow on the ceiling (you may need to move the flashlight around to get the perfect angle). Note: It may take several tries to get the angle of the flashlight just right. You may want to practice before demonstrating in front of students.

Once students have seen the rainbow, turn on the lights and ask the following questions: “When we saw the rainbow in the picture it was outside. Did you just see a rainbow? Were we outside? How could we see a rainbow outside and a rainbow inside?” Use probing questions to get students to draw conclusions about how the rainbows were made. Students will not have an understanding about light reflecting off the water, but they should begin to understand that light and water caused the rainbow to appear.

Note: The following investigation can be done with students in groups or pairs.

Tell students they are now going to make their own rainbow. They will do an investigation. Say: “Let’s begin this investigation by first following some safety rules. I am going to give you supplies to try to make a rainbow. You need to follow some steps and then explore.” Tell students they will be given a flashlight, but they will only shine the flashlight in one direction: down. All students will also be given a CD. They must hold the CD a certain way. Demonstrate how the CD is to be held and remind students of safety rules.

1. Have students sit or stand facing a wall.
2. Give each person a flashlight and a CD.
3. Have students check with a student next to them to make sure they are holding the CD correctly.
4. Pass by students and turn their flashlights on.
5. Allow students time to investigate what happens.

When students have had time to explore making rainbows ask: “Did you make a rainbow? What do you think made my rainbow and your rainbow?” Students should now be able to answer that the flashlight made the rainbow appear. Some may even connect the idea that shining the flashlight on the CD and water made the rainbow on the wall.

Discuss with students the two investigations (your demonstration and the student investigation). Say: “Who can name the steps we did in both of these investigations?” Students should be able to say in their own words that in each investigation, questions were asked, investigations were done, and questions were answered.

Show the rainbow picture again. Ask students: “What made the rainbow appear outside? There is no giant flashlight.” Students should draw the conclusion that light from the sun caused the rainbow to appear.

Give each student a Making Rainbows worksheet (S-K2-13-3_Making Rainbows Worksheet.doc). Remind students they are to draw what they saw during both your demonstration and the student investigation. Then ask them to write in their own words what they did and what they saw. You may need to help some students write their ideas.

Extension:

• Students who might be going beyond the standards can try to make a rainbow outside using a garden hose.
• Students who might be going beyond the standards can make a rainbow using a clear glass, water, and a flashlight. (Caution students when using glass containers.)
• Students who might need opportunities for practice should review the steps of the scientific method and recall what they did in the rainbow investigation.