Life Science Chapter 2 Section 2 Study Guide
Dr. Karoline Rostamiani
Visible light and Color (Pages 46-50)
Students should be able to
1. Describe how white light interacts with an object.
2. Describe what determines the color of an opaque object.
3. Explain how mixing pigments is different from mixing colors of light.
Key Terms
Transparent
Translucent
Opaque
Primary colors
Secondary colors
Complementary colors
Pigment
Visible Light (page 47)
Key Concept: When light strikes an object, the light can be reflected, transmitted, or absorbed.
What happens to the light depends on the type of material the object is made of.
Materials can be transparent, translucent, or opaque. It depends on what happens to the light that hits
the material.
 Transparent materials let most light pass right through. You can see clearly through a
transparent material. Clear glass is a transparent material.
 Translucent materials scatter light as it passes through. You can see things through a
translucent material, but the details are blurred. Wax paper is a translucent material.
 Opaque materials do not let light pass through. They reflect or absorb all the light that hits
them. When materials absorb light, they take in light. You cannot see anything through an
opaque material. Wood is an opaque material.
The Color of Objects (page 48)
Key Concept: The color of an opaque object is the color of the light it reflects.
 The color of any object depends on what the object is made of and the color of light that hits it.
 Objects made of opaque materials reflect some light and absorb the rest. The color of the
reflected light gives an opaque object its color. For example, an apple looks red because it
reflects red light and absorbs light of other colors.
 Objects change color if you view them in a different color of light. In green light, an apple looks
black. It looks black because there is no red light for it to reflect.
Combining Colors (pages 49-50)
Key Concept: When combined in equal amounts, the three primary colors of light produce white light.
As pigments are added together, fewer colors of light are reflected and more are absorbed.
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Life Science Chapter 2 Section 2 Study Guide
Dr. Karoline Rostamiani
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Primary colors are three colors that can mix together to make any other color. Two primary
colors mix in equal amounts to make a secondary color.
Primary colors of light are red, green, and blue. Secondary colors of light are yellow (red and
green), cyan (blue and green) and magenta (blue and red). Equal amounts of all three primary
colors of light mix together to make white light. Any two colors that combine to form while light
are called complementary colors.
Pigments are colored material. They are used to color inks and paints. Pigments have different
primary and secondary colors than light.
Primary colors of pigments are yellow, cyan and magenta. Secondary colors of pigments are red
(yellow and magenta), green (yellow and cyan) and blue (cyan and magenta). When equal
amounts of all three primary pigment colors are mixed together, the mixture looks black.
A wide range of colors can be produced using just a few basic colors.
 Three colors that can combine to make any other color are called primary colors.
 Two primary colors combine in equal amounts to produce a secondary color.
 The primary colors of light are red, green and blue.
o The secondary colors of light are yellow (red + green), cyan (green + blue), and magenta
(red + blue).
 When combined in equal amounts, the three primary colors of light produce white light.
 If the three primary colors of light are combined in different amounts, they can produce other
colors.
 Complementary colors are a primary color and a secondary color that can combine to form
white light. Blue and yellow are examples of complementary colors.
 Pigments are colored substances that are used to color other materials.
o They include inks, paints, and dyes.
o The color of a pigment is the color of light that the pigment reflects.
o As pigments are added together, fewer colors of light are reflected and more are
absorbed.
o The more pigments that are combined, the darker the mixture looks.
o The primary colors of pigments are cyan, yellow and magenta.
o The secondary colors of pigments are red, green and blue.
o The primary pigment colors combine in equal amounts to produce black.
o Many other colors of pigments can be produced by combining the primary pigment
colors in different amount.
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Life Science Chapter 2 Section 2 Study Guide
Dr. Karoline Rostamiani
Primary Light Colors
How we see color.
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All Visible light hits the red apple.
The red apple absorbs all light except red. It reflects red light.
The human eye receives the reflected red light.
Sample Questions:
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What happens to light that strikes a translucent material
The color of an opaque object is the color of the light it _______________________.
Explain why you see the skin of an apple as red.
The three colors that can be used to make any other color are called _____________________.
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