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Dive into the fascinating world of light with this chapter, where you will learn about its properties, colors, and how our eyes interpret light. Discover the speed of light, compare incandescent and fluorescent light, and explore the creation of color through light. Uncover how light waves work, the additive and subtractive color processes, and even how plants use light for growth. This chapter will broaden your understanding of light and optics, from its intensity to its role in vision.
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Chapter 22 Physics A First Course Light and Optics
Light and OpticsLight and Color • 22.1 Properties of Light • 22.2 Vision and Color • 22.3 Using Color
Describe the properties of light. Review the term light intensity. Learn about the speed of light. Be able to compare light and sound waves. Chapter 22.1 Objectives and Vocabulary • incandescence • fluorescence • intensity
Incandescent vs. Fluorescent Light Fluorescent bulbs are four times more efficient.
Speed of Sound vs. Speed of Light • Light travels almost a million times faster • Light travels around the earth 7.5 times per second
Key Question: How is color created by light? 22A Investigation: Light and Color *Students read text section 22.2 AFTER Investigation 22A
22A Investigation Topics • Compare sources of light. • Mix colors of light. • Describe how the human eye sees color. • Explain how printers make colors.
white light photoreceptors cones rods Describe white light and color. Learn how our eyes see light and interpret color. Learn about the additive color process. Learn that light is a wave, but also made of particles called photons. Chapter 22.2 Objectives and Vocabulary • additive color process • additive primary colors
How the human eye sees light • Photoreceptors release chemical signals. • Chemical signals travel to the brain along the optic nerve. optic nerve
Cones respond to three colors: red, green and blue. Rods detect intensity of light: black, white, shades of gray. Photoreceptors in the eye
Which chemical signal gets sent depends on how much energy the light has. If the brain gets a signal from ONLY green cones, we see green. How we see colors
Learn about the subtractive color process. Compare the CMYK and RGB processes. Learn about color blindness. Learn how plants use light and color to grow. Chapter 22.3 Objectives and Vocabulary • subtractive color process • subtractive primary colors • CMYK color process • RGB color process
Normal vision Weak green color vision No red color vision Color Blindness
Plants absorb energy from light and convert it to chemical energy in the form of sugar (food for the plant). Chlorophyll is an important molecule that absorbs blue and red light. Plants use color
Key Question: What is the difference between reflection and refraction? 22B Investigation: Reflection and Refraction *Students read text section 22.3 BEFORE Investigation 22B and text section 23.1 should follow it.
22B Investigation Topics • Observe the law of reflection. • Draw ray diagrams. • Observe light rays passing through a prism. • Observe refraction and reflection at the same time. • Determine the angle of refraction.