WHAT YOU SEE IS WHAT YOU GET
Grades 4-6

In this lesson, students will be learning about light and colors. They will see how white light is made up of various colors. Students need to have some background knowledge about prisms, light wave lengths, and behavior of light, primary and secondary colors, and ratios.

Bill Nye: The Science Guy, Color and Light

Students will be able to:

• expand how colors of lights mix to form white light.
• name the colors that make up a white light (rainbow)
• write the ratios of primary colors to secondary colors of a rainbow.

• 3 flashlights
• red, blue, and green cellophane
• 3 rubber bands

Teacher: Why is the sky blue? Why is the board white? Why is the poster red? (List the responses on the board.) Today we are going to answer the following questions. We have learned about the behavior of light earlier. Today we are going to learn how light gives off color, or how we see color.

To give students a specific responsibility while viewing, ask them to look for why we see certain colors, and to identify the colors of the spectrum (rainbow). Teacher: We are going to watch a video over color. As we watch the first part, listen for the answer of these questions: What is white light? What do we actually see when we see things.

BEGIN video. PAUSE after Bill asks, "What is happening to all of the other colors?" Teacher: What is light? (After correct response the ask,) What do we actually see when we see things? (After correct response go back to Bill's question.) "If white light is made up of all of those different colors, why don't we see them in Bill's Tie? What happens to those colors? (Allow time for student and then tell students to watch and listen for the answer.) RESUME video. PAUSE after Bill says, "...because they are absorbing light." Teacher: What happens to those colors we cannot see? (After correct response ask students,) What color do we get when all light is absorbed? (Allow time for responses then resume video.) RESUME video. PAUSE at black dog. Teacher: What color do we get when all light is absorbed? Great! Now let's find out how we see certain colors. Listen carefully for the answer. RESUME video. (fast forward to BNSG Sports, Bill Nye playing tennis). PAUSE where boy is holding up sign. Teacher: So why is the poster red? (After appropriate answer ask,) Who can name the colors of a rainbow? (After response tell students,) Listen for the colors of the rainbow, the acronym used to help learn them, and figure out the ratio of primary colors to the other colors in the rainbow. RESUME video.(FAST FORWARD to end of crayon segment to where lady says, "It's art, it's science." PAUSE after Bill says Roy G. Biv. Teacher: What are the colors of the spectrum (rainbow?) How can we remember what they are? Now, what is the ratio of primary colors to the rest of colors? One of the questions I asked at the beginning of class was why was the sky blue. Let's take a look at the video to see why it is blue. RESUME video. (REWIND to a soap dish bubble float, in the air.) PAUSE as they fade out of the black and white footage. Teacher: Why is the sky blue? Now we see how light works in order for us to see color. Let's do an experiment to prove what we just watched.

Teacher: How can we make white light from colored light. cover the end of a flashlight with a piece of red cellophane. Fasten tightly with a rubber band. In the same way, cover a second flashlight with blue cellophane and cover a third flashlight with green cellophane. Darken the room. Direct the light from one flashlight onto a white wall or screen. Repeat with each of the other two flashlights. Teacher: What do you observe with each flashlight? Direct red light and blue light from the flashlights onto the screen so that the circles of light overlap. Repeat using all the possible combinations of two or three colors. Teacher: What do you observe? Make a table to record your observations. What combination of colors gives white light? How do your results and conclusions compare with those of your classmates?

Have students test the additive process by putting together different combinations of two colors of light and recording the colors they observe. Then have them write the word Color three times on piece of paper, once in red, once in blue, and once in green. Instruct them to view the word under each color of light and describe what they see.


Write a letter to Dupont asking about the pigmentation process in their paints.

Give groups of students light sources and prisms. Allow the groups to experiment with the materials to produce visible spectra. Inexpensive plastic prisms may be obtained from science supply houses. other cut-glass or cut-plastic objects, such as earrings, crystals, and tumblers with cut-glass bases, also may be used.

Have interested students use reference books to find out the unit used to measure wavelengths. (The angstrom, abbreviated as A) Ask them to determine how many angstroms equal 1 mm. (10 million A per mm) Finally, have students report wavelength ranges for all colors in the spectrum. (Red: 6220-7700 A; Orange: 5970-6220 A; Yellow: 5770-5970 A; Green: 4920-5770 A; Blue: 4550-4920 A; Violet: 3900-4550 A)

Master Teacher's: Jeff and Kristy Parks