Figure 7 The more energy a wave has, the greater is its amplitude. A The amplitude of a transverse wave equals the distance to the highest point above the rest position. B This wave's amplitude is one half the amplitude of the wave in A. Applying Concepts Which wave has more energy?

A diagram of a rope being shaken to determine the amplitude or the maximum displacement of the medium from its rest position of a wave.

Amplitude

If you drop a pebble into a pond, the wave is not very high. If you do a “cannonball” jump into the water, you know the wave will be much higher. These two waves have different amplitudes. The amplitude (AM pluh tood) of a wave is the maximum displacement of the medium from its rest position.

Figure 7 shows the amplitudes of two transverse waves in a rope. The amplitude of a transverse wave is the distance from the rest position to a crest or a trough. It takes more energy to produce a wave with higher crests and deeper troughs. The more energy a wave has, the greater is its amplitude.

How do you measure the amplitude of a longitudinal wave? In this case, the amplitude is the maximum displacement of a point from its rest position. The more energy the wave has, the more the medium will be compressed or displaced.

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Section 17.2 Assessment

Reviewing Concepts

  1. How is the vibration of the source related to a wave's frequency?

  2. How is wavelength related to frequency for waves moving at a constant speed?

  3. How is the energy of a wave related to its amplitude?

  4. Describe two ways you could measure the wavelength of a longitudinal wave.

  5. Describe how you measure the amplitude of a transverse wave.

Critical Thinking

  1. Applying Concepts If a wave's period doubles, how does the wave's frequency change? (Hint: Period=1Frequency)

  2. Designing Experiments Describe an experiment to measure the frequency of a longitudinal wave in a spring.

  3. Predicting If you double the frequency of a wave, what is the effect on its wavelength (assuming speed does not change)?

Math Practice

  1. wave on a rope has a frequency of 3.3 Hz and a wavelength of 1.2 m. What is the speed of the wave?

  2. A spring toy vibrates at 2 Hz to produce a wave. What is the period of the wave?

End ofPage 507

Table of Contents

Physical Science
About the Authors
Contents
    Labs and Activities
    Features
    CHAPTER 1 Science Skills
    1.1 What Is Science?
    1.2 Using a Scientific Approach
    1.3 Measurement
    1.4 Presenting Scientific Data
    CHAPTER 1 Study Guide
      CHAPTER 1 Assessment
        CHAPTER 2 Properties of Matter
        2.1 Classifying Matter
        2.2 Physical Properties
        2.3 Chemical Properties
        CHAPTER 2 Study Guide
        CHAPTER 2 Assessment
        CHAPTER 3 States of Matter
        3.1 Solids, Liquids, and Gases
        3.3 Phase Changes
        CHAPTER 3 Study Guide
        CHAPTER 3 Assessment
        CHAPTER 4 Atomic Structure
        4.1 Studying Atoms
        4.2 The Structure of an Atom
        4.3 Modern Atomic Theory
        CHAPTER 4 Study Guide
        CHAPTER 4 Assessment
        CHAPTER 5 The Periodic Table
        5.1 Organizing the Elements
        5.2 The Modern Periodic Table
        5.3 Representative Groups
        CHAPTER 5 Study Guide
        CHAPTER 5 Assessment
        CHAPTER 6 Chemical Bonds
        6.1 Ionic Bonding
        6.2 Covalent Bonding
        6.3 Naming Compounds and Writing Formulas
        6.4 The Structure of Metals
        CHAPTER 6 Study Guide
        CHAPTER 6 Assessment
        CHAPTER 7 Chemical Reactions
        7.1 Describing Reactions
        7.2 Types of Reactions
        7.3 Energy Changes in Reactions
        7.4 Reaction Rates
        7.5 Equilibrium
        CHAPTER 7 Study Guide
        CHAPTER 7 Assessment
        CHAPTER 8 Solutions, Acids, and Bases
        8.1 Formation of Solutions
        8.2 Solubility and Concentration
        8.3 Properties of Acids and Bases
        8.4 Strength of Acids and Bases
        CHAPTER 8 Study Guide
        CHAPTER 8 Assessment
        CHAPTER 9 Carbon Chemistry
        9.1 Carbon Compounds
        9.2 Substituted Hydrocarbons
        9.3 Polymers
        9.4 Reactions in Cells
        CHAPTER 9 Study Guide
          CHAPTER 9 Assessment
            CHAPTER 10 Nuclear Chemistry
            10.1 Radioactivity
            10.2 Rates of Nuclear Decay
            10.3 Artificial Transmutation
            10.4 Fission and Fusion
            CHAPTER 10 Study Guide
              CHAPTER 10 Assessment
                CHAPTER 11 Motion
                11.1 Distance and Displacement
                11.2 Speed and Velocity
                11.3 Acceleration
                CHAPTER 11 Study Guide
                  CHAPTER 11 Assessment
                    CHAPTER 12 Forces and Motion
                    12.1 Forces
                    12.2 Newton's First and Second Laws of Motion
                    12.3 Newton's Third Law of Motion and Momentum
                    12.4 Universal Forces
                    CHAPTER 12 Study Guide
                      CHAPTER 12 Assessment
                        CHAPTER 13 Forces in Fluids
                        13.1 Fluid Pressure
                        13.2 Forces and Pressure in Fluids
                        13.3 Buoyancy
                        CHAPTER 13 Study Guide
                          CHAPTER 13 Assessment
                            CHAPTER 14 Work, Power, and Machines
                            14.1 Work and Power
                            14.2 Work and Machines
                            14.3 Mechanical Advantage and Efficiency
                            14.4 Simple Machines
                            CHAPTER 14 Study Guide
                              CHAPTER 14 Assessment
                                CHAPTER 15 Energy
                                15.1 Energy and Its Forms
                                15.2 Energy Conversion and Conservation
                                15.3 Energy Resources
                                CHAPTER 15 Study Guide
                                  CHAPTER 15 Assessment
                                    CHAPTER 16 Thermal Energy and Heat
                                    16.1 Thermal Energy and Matter
                                    16.2 Heat and Thermodynamics
                                    16.3 Using Heat
                                    CHAPTER 16 Study Guide
                                      CHAPTER 16 Assessment
                                        CHAPTER 17 Mechanical Waves and Sound
                                        17.1 Mechanical Waves
                                        17.2 Properties of Mechanical Waves
                                        17.3 Behavior of Waves
                                        17.4 Sound and Hearing
                                        CHAPTER 17 Study Guide
                                          CHAPTER 17 Assessment
                                            CHAPTER 18 The Electromagnetic Spectrum and Light
                                            18.1 Electromagnetic Waves
                                            18.3 Behavior of Light
                                            18.4 Color
                                            18.5 Sources of Light
                                              Incandescent Light
                                              CHAPTER 18 Study Guide
                                                CHAPTER 18 Assessment
                                                  CHAPTER 19 Optics
                                                  19.1 Mirrors
                                                  19.2 Lenses
                                                  19.3 Optical Instruments
                                                  19.4 The Eye and Vision
                                                  CHAPTER 19 Study Guide
                                                    CHAPTER 19 Assessment
                                                      CHAPTER 20 Electricity
                                                      20.1 Electric Charge and Static Electricity
                                                      20.2 Electric Current and Ohm's Law
                                                      20.3 Electric Circuits
                                                      20.4 Electronic Devices
                                                      CHAPTER 20 Study Guide
                                                        CHAPTER 20 Assessment
                                                          CHAPTER 21 Magnetism
                                                          21.1 Magnets and Magnetic Fields
                                                          21.2 Electromagnetism
                                                          21.3 Electrical Energy Generation and Transmission
                                                          CHAPTER 21 Study Guide
                                                            CHAPTER 21 Assessment
                                                              CHAPTER 22 Earth's Interior
                                                              22.1 Earth's Structure
                                                              22.2 Minerals
                                                              22.3 Rocks and the Rock Cycle
                                                              22.4 Plate Tectonics
                                                              22.5 Earthquakes
                                                              22.6 Volcanoes
                                                              CHAPTER 22 Study Guide
                                                                CHAPTER 22 Assessment
                                                                  CHAPTER 23 Earth's Surface
                                                                  23.1 Fresh Water
                                                                  23.2 Weathering and Mass Movement
                                                                  23.3 Water Shapes the Land
                                                                  23.4 Glaciers and Wind
                                                                  23.5 The Restless Oceans
                                                                  23.6 Earth's History
                                                                  CHAPTER 23 Study Guide
                                                                    CHAPTER 23 Assessment
                                                                      CHAPTER 24 Weather and Climate
                                                                      24.1 The Atmosphere
                                                                      24.2 The Sun and the Seasons
                                                                      24.3 Solar Energy and Winds
                                                                      24.4 Water in the Atmosphere
                                                                      24.5 Weather Patterns
                                                                      24.6 Predicting the Weather
                                                                      24.7 Climate
                                                                      CHAPTER 24 Study Guide
                                                                        CHAPTER 24 Assessment
                                                                          CHAPTER 25 The Solar System
                                                                          25.1 Exploring the Solar System
                                                                          25.2 The Earth-Moon System
                                                                          25.3 The Inner Solar System
                                                                          25.4 The Outer Solar System
                                                                          CHAPTER 25 Study Guide
                                                                            CHAPTER 25 Assessment
                                                                              CHAPTER 26 Exploring the Universe
                                                                              26.1 The Sun
                                                                              26.2 Stars
                                                                              26.3 Life Cycles of Stars
                                                                              26.4 Groups of Stars
                                                                              26.5 The Expanding Universe
                                                                              CHAPTER 26 Study Guide
                                                                                CHAPTER 26 Assessment
                                                                                  Skills and Reference Handbook
                                                                                  Skills Handbook
                                                                                  Appendices
                                                                                  Glossary
                                                                                  Spanish Glossary
                                                                                  Index
                                                                                    Acknowledgments
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