Investigating the World of Colors
What humans normally notice most about light is color, which originates from the visible spectrum. The colors that we see usually result from the way light is reflected or absorbed. The reason something like an apple appears red, for instance, is because all of the colors in white light are absorbed by the apple except red, which is reflected to our eyes.
The colors that make up white light from longest to shortest wavelength are red, orange, yellow, green, blue, indigo, and violet. In any system of colors, those that cannot be mixed from any of the others are called primary colors. The primary colors of light are red, green, and blue. From these three colors every other color of light can be made.
Paint pigments mix differently than light. The type of color mixing familiar to artists is done with paints or pigments, not lights. Primary pigments in paint can vary, however, red, yellow, and blue are the most common ones.
- Science notebook
- White unlined paper
- Red, blue, and green colored cellophane or transparent report covers
- Rubber bands
- Water and watercolors
- 1 strip of red, yellow, blue, green, orange, and violet construction paper
In order to study the primary colors of light, you and two other students will take a flashlight, and cover the front of each flashlight with colored cellophane. One of you will use red, one will use blue, and the other will use green. The room needs to be dark, and you and your partners need to stand close to a wall or have a piece of white paper taped to the wall for this to work.
Shine the green flashlight on the wall. Shine the red flashlight on the same spot on the wall.
What new color is made in the area where the green light overlaps or partly covers the red light that is shining on the paper?
Shine the red flashlight on the wall. Shine the blue flashlight on the same spot on the wall.
What new color is made in the area where the red light overlaps or partly covers the blue light that is shining on the wall?
Shine the green light on the wall and the blue light on the wall.
What new color is made in the area where the green light overlaps or partly covers the blue light that is shining on the wall?
Try to make the light shining on the wall a white light. In your science notebook, explain how you did this.
In this part of the activity, you are going to experiment with mixing colored pigments and see the relationship between primary colors, secondary colors, and complementary colors. You will need your blank color wheel and your science notebook to answer questions as you do this activity. You will also need the three primary colors of either tempera paint or watercolors. They are red, yellow, and blue.
Color the red, yellow, and blue sections of the color wheel. You have now colored the primary colors. These primary colors are basic and cannot be mixed from other colors.
On a piece of paper, mix the primary colors to get the secondary colors that remain on the blank color chart. Answer the following questions in your science notebook:
What two colors are mixed to form orange?
What two colors are mixed to form violet?
What two colors are mixed to form green?
What color do you get when you mix the three primary colors?
What do you think will happen if you mix yellow and blue paint in different amounts?
What happens when you start with a small amount of yellow paint and begin adding blue a little at a time?
Would you get the same results if you start with blue paint and add yellow paint a little at a time?
The colors opposite each other on the color wheel, such as blue and orange are called complementary colors. The complementary colors are the hues that are as different from each other as possible.
What color is complementary to yellow?
What color is complementary to red?
You can use complementary colors to change the intensity of a hue. If you pick a color, such as orange, and mix in a little of its complementary color, the orange will still be orange, but not as bright; adding the complementary color reduces its brightness. Try it and record what happens in your science notebook.
Find out about how artists use color. You can create a painting using primary colors or secondary colors. Many artists chose to either paint works of art emphasizing primary colors or secondary colors. Research some of the artists such as Matisse, Picasso, Mondrian, Hokusai or Frieda Kahlo who emphasized the primary colors in their work or Cezanne, Vasarely, or O'Keefe who emphasized secondary colors.
For the third part of the activity, you will make color wheel flash cards. You will work with a partner, but each of you should make your own color flash cards.
Cut strips of red, yellow, blue, green, orange, and violet construction paper to make up a set of color wheel flash cards. Cards should be about 8 x 18 centimeters. You may also use index cards and glue or paste strips of colored paper to them.
Choose a color. Now think about a question you can ask that relates to that color. For example, "Is red a primary or secondary color?" or "What is the complementary color of red?" If you choose orange you might ask, "Is orange a primary or secondary color?" or "Can you make orange from two other colors and, if so, which ones?"
Write your questions on the back of the color flashcard. This way, when you hold up the card, your partner can see the color while you read the question.
Ask your partner 10 questions about the colors on the color wheel. When your partner can answer most of the questions, switch roles and have your partner ask you questions.
BACK TO ACTIVITIES IN OPTICS
BACK TO THE TEACHER GUIDEBOOK
Questions or comments? Send us an email.
Last Modification Friday, Aug 01, 2003 at 10:43 AM
Access Count Since November 1st, 2000: 55536
Visit the websites of our partners in education: