module o: chapter 1 the energy of waves section 1: the...
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The Energy of Waves Module O: Chapter 1
Section 1: The Nature of Waves Section 2: Properties of Waves Section 3: Wave Interactions
Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide
The Nature of Waves Section 1
Objectives • Describe how waves transfer energy without transferring matter.
• Distinguish between waves that require a medium and waves that do not.
• Explain the difference between transverse and longitudinal waves.
Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide
The Nature of Waves Section 1
Wave Energy • Waves and Work As a wave travels, it does work on everything in its path. Wave motion is shown on the next slide.
• Energy Transfer Through a Medium Most waves transfer energy by the vibration of particles in a medium. A medium is a substance through which a wave can travel.
• Energy Transfer Without a Medium Some waves can transfer energy without going through a medium. Visible light is one example. Waves that do not need a medium are electromagnetic waves.
Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide
Wave Motion
Section 1
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The Nature of Waves
Section 1
Types of Waves • Transverse Waves Waves in which the particles vibrate in an up-and-down motion are called transverse waves. Ex. Electromagnetic waves • Longitudinal Waves In a longitudinal wave, the particles of the medium vibrate back and forth along the path that the wave moves. • Need a medium • The more dense the medium the easier energy transferred • Mechanical waves
• Ex: sound waves
Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide
The Nature of Waves
Section 1
Types of Waves continued
• Sound Waves Sound waves travel by compressions and rarefactions of air particles.
• Combinations of Waves A transverse wave and a longitudinal wave can combine to form a surface wave.
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Comparing Longitudinal and Transverse Waves
Section 1
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Properties of Waves Section 2
Objectives
• Identify and describe four wave properties.
• Explain how frequency and wavelength are related to the speed of a wave.
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Properties of Waves
Section 2
Amplitude
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• What Is Amplitude? The amplitude of a wave is related to its height. A wave’s amplitude is the maximum distance that the particles of a medium vibrate from their rest position.
• Larger Amplitude—More Energy A wave with a large amplitude carries more energy than a wave with a small amplitude does.
End of Slide
Properties of Waves
Section 2
Wavelength
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• What Is a Wavelength? A wavelength is the distance between any two crests or compressions next to each other in a wave.
• Shorter Wavelength—More Energy A wave with a shorter wavelength carries more energy than a wave with a longer wavelength does. The next slide shows how to measure wavelength.
End of Slide
Measuring Wavelength
Section 2
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Properties of Waves
Section 2
Frequency
• What Is Frequency? The number of waves produced in a given amount of time is the frequency.
• Higher Frequency—More Energy If the amplitudes are equal, high-frequency waves carry more energy than low-frequency waves.
Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide
Properties of Waves
Section 2
Wave Speed • What Is Wave Speed? Wave speed is the speed at which a wave travels.
• Frequency and Wavelength Relationship Three of the basic properties of a wave are related to one another in the wave equation—wave speed, frequency, and wavelength. If you know any two of these properties of a wave, you can use the wave equation to find the third. One of the things the wave equation tells you is the relationship between frequency and wavelength. If a wave is traveling a certain speed and you double its frequency, its wavelength will be cut in half.
Copyright © by Holt, Rinehart and Winston. All rights reserved. End of Slide
Wave Interactions Section 3
Reflection
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• What Is Reflection? Reflection happens when a wave bounces back after hitting a barrier.
• Transmitting a Wave Waves are not always reflected when they hit a barrier. If all light waves were reflected when they hit your eyeglasses, you would not be able to see anything! A wave is transmitted through a substance when it passes through the substance.
End of Slide
Wave Interactions Section 3
Refraction
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• What Is Refraction? Refraction is the bending of a wave as the wave passes from one medium to another at an angle.
• Refraction of Different Colors When light waves from the sun pass through a droplet of water in a cloud or through a prism, the light is refracted. But the different colors in sunlight are refracted by different amounts, so the light is dispersed,or spread out, into its separate colors.
End of Slide