Color Sleuths

Objectives:

• The students will explore color changes through the use of different color plastics and cellophane filters. The color of objects is recorded according to the color change viewed through the different filters. Students will predict and record how each color filter actually affects viewing of each object.
  

• How do filters change the way the world looks? Students will also use color filters over a flashlight beam, to shine different colored light on objects. They will compare their results to those previously recorded.
  

• Students will "read" a remote sensing image using a color key composite to identify how an infrared image may depict colors on the ground, differently from those the human eye would perceive. Students will learn to identify different objects/landscapes using the color key provided.
  

Time Duration:
Two 45-minutes sessions. (Three periods will be required if students make the filters.)

Grade Level: 4-5

Concepts Explored:
scientific processes, energy, communication, comparison, inference, classification, sequencing, organization, evaluation and synthesis

Vocabulary:
filters, characteristics, similarities, differences, refraction, reflection, spectrum, infrared, color composite, and color key

Grouping: groups of 4

Materials Per student:

• recording grid chart, part 1
  and
• recording grid chart, part2

Materials Per Group:

• 1 set of "viewing filters", red, blue, green and clear; (report covers can be used here)
  
• pictures, posters or photographs
  
• colored objects/papers: red apple, green leaf, yellow, blue, etc.
  
• colors/crayons
  
• 1 flashlight
  
• a remote sensing color aerial photograph showing the color composite key
  

Materials Per Class:

• overhead- student chart
  
• color overhead of same remote image not in the infrared
  
• photo

Advanced Preparation:
Gather posters of art, perhaps a pointillism, impressionist or Rembrandt, also photographs or colorful illustrations from magazines. Laminate these pages for lasting use. You should decide if you or your students will make the "filter viewers" with cellophane of different colors and with a manila folder to hold the filter. The finished product should resemble a large magnifying glass as in the figures below. The cellophane should be mounted in the center of the folder. It should have a handle to hold.

or

Prepare a set of two templates of "Mystery Messages" using the same colors in each, for each team to decode using the filters (i.e. like the sweepstakes windows decoders using a red filter to find the message).

Teacher Resources:
old National Geographic; Ranger Rick; 3,2,1, Contact and/or any nature magazines, art prints or posters

Technology: 3,2,1, Contact Video on Light

Teaching Tips:
Develop a picture file of animals, panoramas such as nature's calendar pictures. Send a notice to your parents requesting these, also someone to cut and paste them onto construction paper.

Have at hand resource books about light and color, so the students can investigate further their interest in light and how it affects our world. "ABC of Nature" from Readers Digest and "Light and Color" from Life Encyclopedia.

Procedure:

Day 1 (if filters are pre-made)-

1. Ask: Why does an apple look red? Does an apple always look red?

2. Guide students through a discussion of possible colors of apples.

3. Make a chart of predictions of which colors would a red apple look like, if seen through filters of different colors. Continue predictions for all the materials provided for viewing and demonstrate recording on a class chart (overhead of student's recording page). The student recording page needs to have two sets of conclusions, one for each grid, to be aligned back to back, so when photocopied, teacher can cut in half the page for each day, or students use only top portion on the first day and bottom portion the next.

4. Distribute the filters and instruct students to see each object through one of their color filters, one at a time. Record the color of the object as viewed through the different color filters.

5. Have students discuss their findings and come up with ideas of why this might be happening. In order to evaluate their conclusions, do more explorations.

6. Write with color pens on a piece of paper. Look through the filters. Can you see every letter? What colors look bright through your filters? Which ones 'disappear'? Pass out the teacher-made "Mystery Messages" templates for students to decode. Encourage students to write their own mystery message, once they have discovered the hues that the filter affects as a key to decode it. Look at the room around through your new pair of 'color eyes'. What do you see?

7. How come we can see things differently when we put a color filter in front of it?

Day 2:

1. Experiment with the filters and lights. What happens to objects if we shine a filtered light on them? What color they it be? Why? What information might we be able to learn from applying this information to the real world? Where do people use filters to shine on objects?

2. Write down other questions and conclusions you might have. Share the "what" and the "how" you discovered.

3. Having compared the perception of color reflection and refraction through colored filters, we see that objects seem to change color depending on the light that shines upon them and the viewing mechanism used to see them. We are going to view some images from the technology called Remote Sensing. Through the use of remote sensing equipment, or seeing from afar, sensors can make images of the world from different distances, using mechanisms that allow for the sensors to pick up information using different wavelengths of the electromagnetic spectrum as points of reference. One way of viewing a scene or image is by using a portion of the infrared wavelengths. Such an image, if viewed by us in the infrared would be out of our perception range, beyond the visible red end of the spectrum. Look at the remote sensing image provided. How is it different from the color photograph overhead? How is it similar?

4. In the image provided, there is a color composite key, showing what wavelengths this particular remote sensor was able to pick up. Using the key, identify on the image the following features:
   • Locate trees or plant growth

   • Locate urban development

   • Locate water

   • Locate land, soil or sands - no vegetation growth/no urban growth.

5. To find a forest, what range of colors would you use in the infrared image? If you need to locate cities, what colors might you seek? Soils? Sands? Water? Is technology (being able to see in the infrared) important? Explain.

Extensions:

• Students will continue to be amazed at the effects of filters in their vision. Maintain a set of filters on a discovery area, to compare their clothes or bulletin boards throughout the year. Encourage them to find out more about color through your art activities and reading assignments.

• Invite a photographer/artist to explain the use of color/media in their work.

• Experiment putting color cellophane sheets over growing plants and see the effect of different colored light on their growth. Keep a log on predictions and observations.

• Make 3-D glasses, with one lens being a blue filter and the other one red. Draw words and geometrical shapes with blue and red pens, so there are solid lines in one color and dotted lines in the other color, so as to double the image of each figure. Look through the glasses and be AMAZED!

• Invite students to look for remote sensing images in publications and build a bulletin board/ resource file of images. Develop color keys for the composition of the images to identify differences and similarities among them.

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