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Chapter 23 Preview Section 1 Mirrors and Lenses
Light and Our World Preview Section 1 Mirrors and Lenses Section 2 Light and Sight Section 3 Light and Technology Concept Mapping
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Chapter 23 Section 1 Mirrors and Lenses Bellringer What is the difference between a mirror and a lens? What is the difference between a convex mirror and a concave mirror? Can you think of one common use for a convex lens and for a concave lens? Record your responses in your science journal.
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Chapter 23 Section 1 Mirrors and Lenses Objectives Use ray diagrams to show how light is reflected or refracted. Compare plane mirrors, concave mirrors, and convex mirrors. Use ray diagrams to show how mirrors form images. Describe the images formed by concave and convex
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Rays and the Path of Light Waves
Chapter 23 Section 1 Mirrors and Lenses Rays and the Path of Light Waves A Ray of Light Because light waves travel in straight lines, you can use an arrow called a ray to show the path and the direction of a light wave. Rays and Reflected and Refracted Light Rays help to show the path of a light wave after it bounces or bends.
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Mirrors and Reflection of Light
Chapter 23 Section 1 Mirrors and Lenses Mirrors and Reflection of Light Plane Mirrors A plane mirror is a mirror that has a flat surface. The reflection of an object in a plane mirror is right side up and the same size as the object, but reversed left to right. Plane mirrors form virtual images. A virtual image is an image through which light does not travel
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Chapter 23 Section 1 Mirrors and Lenses
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Mirrors and Reflection of Light, continued
Chapter 23 Section 1 Mirrors and Lenses Mirrors and Reflection of Light, continued Concave Mirrors A concave mirror is a mirror that is curved inward. The image formed by a concave mirror depends on the optical axis, focal point, and focal length of the mirror.
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Chapter 23 The Optical Axis, Focal Point, and Focal Length
Section 1 Mirrors and Lenses The Optical Axis, Focal Point, and Focal Length
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Mirrors and Reflection of Light, continued
Chapter 23 Section 1 Mirrors and Lenses Mirrors and Reflection of Light, continued Concave Mirrors and Ray Diagrams Draw a ray diagram to determine if a concave mirror will form a virtual image like a plane mirror, or a real image. A real image is an image through which light passes.
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Chapter 23 How Images Are Formed in Concave Mirrors
Section 1 Mirrors and Lenses How Images Are Formed in Concave Mirrors
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Mirrors and Reflection of Light, continued
Chapter 23 Section 1 Mirrors and Lenses Mirrors and Reflection of Light, continued Convex Mirrors A convex mirror is a mirror that curves outward. The image formed by a convex mirror is always virtual, right side up, and smaller than the original object.
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Convex Mirror Ray Diagram
Chapter 23 Section 1 Mirrors and Lenses Convex Mirror Ray Diagram
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Lenses and Refraction of Light
Chapter 23 Section 1 Mirrors and Lenses Lenses and Refraction of Light A lens is a transparent object that forms an image by refracting, or bending, light. Two kinds of lenses are convex and concave.
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Chapter 23 How Light Passes Through Concave and Convex Lenses
Section 1 Mirrors and Lenses How Light Passes Through Concave and Convex Lenses
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Lenses and Refraction of Light, continued
Chapter 23 Section 1 Mirrors and Lenses Lenses and Refraction of Light, continued Convex Lenses A convex lens is thicker in the middle than at the edges.
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Lenses and Refraction of Light, continued
Chapter 23 Section 1 Mirrors and Lenses Lenses and Refraction of Light, continued Concave Lenses A concave lens is thinner in the middle than at the edges.
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Chapter 23 Section 2 Light and Sight Bellringer Answer the following questions in your science journal. What do you think a person who has colorblindness sees? If you have colorblindness, describe what you see. What difficulties would a person who has colorblindness have?
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Chapter 23 Section 2 Light and Sight Objectives Identify the parts of the human eye, and describe their functions. Describe three common vision problems. Describe surgical eye correction.
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Chapter 23 How You Detect Light
Section 2 Light and Sight How You Detect Light Your eye gathers visible light to form the images that you see. The thickness of the lens of the eye changes so that objects at different distances can be seen in focus. The light that forms a real image on the retina is detected by receptors called rods and cones. The next slide explains how your eyes work.
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Chapter 23 Section 2 Light and Sight
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Common Vision Problems
Chapter 23 Section 2 Light and Sight Common Vision Problems Nearsightedness happens when a person’s eye is too long. A nearsighted person can see something clearly only if it is nearby. Faraway objects look blurry. Farsightedness happens when a person’s eye is too short. A farsighted person can see faraway objects clearly. But things that are nearby look blurry.
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Common Vision Problems, continued
Chapter 23 Section 2 Light and Sight Common Vision Problems, continued The images below explain how nearsightedness and farsightedness can be corrected with glasses.
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Common Vision Problems, continued
Chapter 23 Section 2 Light and Sight Common Vision Problems, continued Color Deficiency is another name for colorblindness. The majority of people who have color deficiency can’t tell the difference between shades of red and green or can’t tell red from green. Color deficiency happens when the cones in the retina do not work properly. Color deficiency cannot be corrected.
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Surgical Eye Correction
Chapter 23 Section 2 Light and Sight Surgical Eye Correction Surgical eye correction works by reshaping the patient’s cornea by using a laser. Patients often gain perfect or nearly perfect vision after surgery. Risks of Surgical Eye Correction Some patients report glares, double vision, or trouble seeing at night. People under 20 years old should not have surgical eye correction because their vision is still changing.
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Chapter 23 Section 3 Light and Technology Bellringer Can you describe what a laser is? List at least four uses for lasers. Explain your answers in your science journal.
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Chapter 23 Objectives Describe three optical instruments.
Section 3 Light and Technology Objectives Describe three optical instruments. Explain what laser light is, and identify uses for lasers. Describe how optical fibers work. Explain polarized light. Explain how radio waves and microwaves are used in four types of communication technology.
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Chapter 23 Optical Instruments
Section 3 Light and Technology Optical Instruments Optical instruments are devices that use mirrors and lenses to help people make observations. Cameras A camera is used to record images. All cameras have a lens, shutter, and an aperture. A 35 mm camera records images on film. A digital camera uses light sensors to record images and to send electric signals to a computer.
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Chapter 23 Section 3 Light and Technology
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Optical Instruments, continued
Chapter 23 Section 3 Light and Technology Optical Instruments, continued Telescopes Telescopes are used to see detailed images of large, distant objects. Refracting telescopes use lenses to collect light. Reflecting telescopes use mirrors to collect light.
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Chapter 23 How Refracting and Reflecting Telescopes Work
Section 3 Light and Technology How Refracting and Reflecting Telescopes Work
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Optical Instruments, continued
Chapter 23 Section 3 Light and Technology Optical Instruments, continued Light Microscopes Microscopes are used to study tiny, nearby objects. Microscopes have two convex lenses. An objective lens is close to the object being studied. An eyepiece lens is in the lens you look through.
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Chapter 23 Lasers and Laser Light
Section 3 Light and Technology Lasers and Laser Light A laser is a device that produces intense light of only one wavelength and color. How Lasers Produce Light The word laser stands for light amplification by stimulated emission of radiation. Amplification is the increase in the brightness of the light. Radiation is energy transferred as electromagnetic waves.
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Chapter 23 Laser Light is Differs from Nonlaser Light
Section 3 Light and Technology Laser Light is Differs from Nonlaser Light
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Chapter 23 Section 3 Light and Technology
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Lasers and Laser Light, continued
Chapter 23 Section 3 Light and Technology Lasers and Laser Light, continued Uses for Lasers Lasers are used to make holograms. A hologram is a piece of film that produces a three-dimensional image of an object. Lasers have many other applications. They are used to cut materials such as metal and cloth. Doctors sometimes use lasers for surgery. CD players use lasers to read CDs.
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Chapter 23 Optical Fibers
Section 3 Light and Technology Optical Fibers An optical fiber is a thin, glass wire that transmits light over long distances. Optical fibers are used to transmit information through telephone cables and network computers. Doctors use optical fibers to see inside patients’ bodies.
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Optical Fibers, continued
Chapter 23 Section 3 Light and Technology Optical Fibers, continued Light in a Pipe Optical fibers are like pipes that carry light. Light stays inside an optical fiber because of total internal reflection, the complete reflection of light light along the surface of the material.
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Chapter 23 Section 3 Light and Technology
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Chapter 23 Polarized Light
Section 3 Light and Technology Polarized Light Polarized light consists of light waves that vibrate in only one plane. Some sunglasses and camera lenses use polarized filters to reduce glare.
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Chapter 23 Polarizing Filters Reduce Glare
Section 3 Light and Technology Polarizing Filters Reduce Glare
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Communication Technology
Chapter 23 Section 3 Light and Technology Communication Technology Light waves, radio waves, and microwaves are all types of electromagnetic waves. Cordless telephones and cellular telephones use radio waves and microwaves to send signals. Cordless Telephones The base of a cordless telephone changes the signal it receives into radio waves. The handset changes the radio waves into sound.
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Communication Technology, continued
Chapter 23 Section 3 Light and Technology Communication Technology, continued Cellular Telephones Cellular telephones send and receives signals from distant towers. Instead of using radio waves like cordless phones, cellular phones use microwaves to send information.
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Communication technology, continued
Chapter 23 Section 3 Light and Technology Communication technology, continued Satellite Technology Microwave signals are broadcast from space to satellite dishes on Earth. Satellites allow more people to receive the signals and to receive higher quality signals than if antennas on Earth were used. The Global Positioning System The GPS is a network of 27 satellites that orbit Earth. A GPS receiver receives signals from at least four satellites to find its exact location.
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Chapter 23 Section 3 Light and Technology
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Chapter 23 Concept Mapping
Light and Our World Concept Mapping Use the terms below to complete the Concept Mapping on the next slide. real convex light lenses virtual mirrors
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Chapter 23 Light and Our World
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Chapter 23 Light and Our World
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