## 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.

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

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