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Science_Lab_Yellow / Lesson 2: How Do Colors Look in Colored Light

How Do Colors Look in Colored Light

What will we be learning today?

  • In this lesson, we are going to learn how do colors look in colored light.

  • How Do Colors Look in Colored Light?

    A color filter is a material that absorbs certain colors of light and allows others to pass through. The color of an object depends on the color of the light hitting it. What if you looked through colored cellophane sheets as color filters? For example, the red cellophane allows red light to pass through it but blocks other colors.



    Try shining a flashlight on a red tomato. Use a sheet of red cellophane as your filter. The tomato still looks red. Now try a green sheet as your filter. Since the tomato can only reflect red light, it now looks black. Try other filters to see how they work.


    If you mixed equal amounts of red, green, and blue light, you would get white light, and the tomato would look red. In fact, all of the colors of the spectrum can be created by mixing proper amounts of red, green, and blue light. For this reason we call red, green, and blue the primary colors of light.


    Our eyes have cells in the retina that react to colors of light. Some cells react only to red, others only to green, and still others only to blue. If the retina is struck with equal amounts of red, green, and blue light, we see white.


    However, if the retina is struck with only red and green light, we see yellow. The drawing below shows some of the different colors that various mixtures of red, green, and blue light can cause us to see.


    Mixing red, green, and blue light.Note that white is formed in the middle.



    Stare steadily at the blue square above. This tires the cells in your eye that react to blue light. After a full minute, quickly look at a piece of white paper. What color do you see? Why?