Conceptual Physical Science Explorations

Chapter 6: Energy

Work

Work occurs when a force is applied over a distance. This, in turn, changes the amount of energy. Duration: 5:50.

VIDEO QUIZ

Table of Videos

Chapter 1: About Science
- 1.1 A Brief History of Advances in Science
- 1.2 Mathematics and Conceptual Physical Science
- 1.3 Scientific Methods—Classic Tools
- 1.4 Scientific Hypotheses Must Be Testable
- 1.5 A Scientific Attitude Underlies Good Science
- 1.6 The Search for Order—Science, Art, and Religion
- 1.7 Technology—Practical Use of the Findings of Science
- 1.8 The Physical Sciences: Physics, Chemistry, Earth Science, and Astronomy
- 1.9 In Perspective
Chapter 2: Newton's First Law of Motion
- 2.1 Aristotle’s Classification of Motion
- 2.2 Galileo’s Concept of Inertia
- 2.3 Galileo’s Concepts of Speed and Velocity
- 2.4 Motion is Relative
- 2.5 Newton’s First Law of Motion—The Law of Inertia
- 2.6 Net Force—The Combination of All Forces That Act on an Object
- 2.7 Equilibrium for Objects at Rest
- 2.8 The Support Force—Why We Don’t Fall Through the Floor
- 2.9 Equilibrium for Moving Objects
- 2.10 Earth Moves Around the Sun
Chapter 3: Newton's Second Law
- 3.1 Galileo Developed the Concept of Acceleration
- 3.2 Force Causes Acceleration
- 3.3 Mass Is a Measure of Inertia
- 3.4 Mass Resists Acceleration
- 3.5 Newton’s Second Law Links Force, Acceleration, and Mass
- 3.6 Friction Is a Force That Affects Motion
- 3.7 Objects in Free Fall Have Equal Acceleration
- 3.8 Newton’s Second Law Explains Why Objects in Free Fall Have Equal Acceleration
- 3.9 Acceleration of Fall Is Less When Air Drag Acts
Chapter 4: Newton's Third Law
- 4.1 A Force Is Part of an Interaction
- 4.2 Newton’s Third Law—Action and Reaction
- 4.3 A Simple Rule Helps Identify Action and Reaction
- 4.4 Action and Reaction on Objects of Different Masses
- 4.5 Action and Reaction Forces Act on Different Objects
- 4.6 The Classic Horse-Cart Problem—A Mind Stumper
- 4.7 Action Equals Reaction
- 4.8 Summary of Newton’s Three Laws
Chapter 5: Momentum
- 5.1 Momentum is Inertia in Motion
- 5.2 Impulse Changes Momentum
- 5.3 Momentum Change is Greater When Bouncing Occurs
- 5.4 When No External Force Acts, Momentum Doesn’t Change—It is Conserved
- 5.5 Momentum is Conserved in Collisions
Chapter 6: Energy
- 6.1 Work—Force x Distance
- 6.2 Power—How Quickly Work Gets Done
- 6.3 Mechanical Energy
- 6.4 Potential Energy Is Stored Energy
- 6.5 Kinetic Energy Is Energy of Motion
- 6.6 Work-Energy Theorem
- 6.7 Conservation of Energy
- 6.8 Machines—Devices to Multiply Forces
- 6.9 Efficiency—A Measure of Work Done for Energy Spent
- 6.10.Sources of Energy
- 6.11 Energy for Life
Chapter 7: Gravity
- 7.1 The Legend of the Falling Apple
- 7.2 The Fact of the Falling Moon
- 7.3 Newton’s Grandest Discovery—The Law of Universal Gravitation
- 7.4 Gravity and Distance: The Inverse-Square Law
- 7.5 The Universal Gravitational Constant, G
- 7.6 The Mass of the Earth Is Measured
- 7.7 Projectile Motion
- 7.8 Fast-Moving Projectiles—Satellites
- 7.9 Earth Satellites in Circular Orbits
- 7.10 Satellites in Elliptical Orbits
- 7.11 Escape Speed—Getting “Out There”
- 7.12 Gravitation Is Universal
Chapter 8: Fluid Mechanics
- 8.1 Density—A Measure of Compactness
- 8.2 Pressure—Force per Area
- 8.3 Buoyancy in a Liquid
- 8.4 Archimedes’ Principle—Sink or Swim
- 8.5 Pressure in a Gas
- 8.6 Atmospheric Pressure Is Due to the Weight of the Atmosphere
- 8.7 Pascal’s Principle—The Transmission of Pressure in a Fluid
- 8.8 Buoyancy in a Gas—More Archimedes’ Principle
- 8.9 Bernoulli’s Principle—Flying With Physics
Chapter 9: Heat
- 9.1 Thermal Energy—The Total Energy in a Substance
- 9.2 Temperature—Average Kinetic Energy Per Molecule in a Substance
- 9.3 Absolute Zero—Nature’s Lowest Possible Temperature
- 9.4 Heat Is the Movement of Thermal Energy
- 9.5 Specific Heat Capacity— A Measure of Thermal Inertia
- 9.6 Thermal Expansion
- 9.7 Conduction—Heat Transfer via Particle Collision
- 9.8 Convection—Heat Transfer via Movements of Fluid
- 9.9 Radiation—Heat Transfer via Radiant Energy
- 9.10 Energy Changes With Changes of Phase
Chapter 10: Electricity
- 10.1 Electric Charge Is a Basic Characteristic of Matter
- 10.2 Coulomb’s Law—The Force Between Charged Particles
- 10.3 Charge Polarization
- 10.4 Electric Current—The Flow of Electric Charge
- 10.5 An Electric Current Is Produced by Electrical Pressure—Voltage
- 10.6 Electrical Resistance
- 10.7 Ohm’s Law—The Relationship Among Current, Voltage, and Resistance
- 10.8 Electric Shock
- 10.9 Direct Current and Alternating Current
- 10.10 Electric Power—The Rate of Doing Work
- 10.11 Electric Circuits—Series and Parallel
Chapter 11: Magnetism
- 11.1 Magnetic Poles—Attraction and Repulsion
- 11.2 Magnetic Fields—Regions of Magnetic Influence
- 11.3 Magnetic Domains—Clusters of Aligned Atoms
- 11.4 The Interaction Between Electric Currents and Magnetic Fields
- 11.5 Magnetic Forces Are Exerted on Moving Charges
- 11.6 Electromagnetic Induction—How Voltage Is Created
- 11.7 Generators and Alternating Current
- 11.8 Power Production—A Technological Extension of Electromagnetic Induction
- 11.9 The Induction of Fields—Both Electric and Magnetic
Chapter 12: Waves and Sound
- 12.1 Special Wiggles—Vibrations and Waves
- 12.2 Wave Motion—Transporting Energy
- 12.3 Two Types of Waves—Transverse and Longitudinal
- 12.4 Sound Travels in Longitudinal Waves
- 12.5 Sound Can Be Reflected
- 12.6 Sound Can Be Refracted
- 12.7 Forced Vibrations and Natural Frequency
- 12.8 Resonance and Sympathetic Vibrations
- 12.9 Interference—The Addition and Subtraction of Waves
- 12.10 The Doppler Effect—Changes in Frequency Due to Motion
- 12.11 Wave Barriers and Bow Waves
- 12.12 Shock Waves and the Sonic Boom
Chapter 13: Light and Color
- 13.1 The Electromagnetic Spectrum
- 13.2 Why Materials Are Either Transparent or Opaque
- 13.3 Reflection of Light
- 13.4 Refraction—The Bending of Light Due to Changing Speed
- 13.5 Illusions and Mirages Are Caused by Atmospheric Refraction
- 13.6 Color Science
- 13.7 Mixing Colored Lights
- 13.8 Mixing Colored Pigments
- 13.9 Why the Sky Is Blue
- 13.10 Why Sunsets Are Red
- 13.11 Why Clouds Are White
Chapter 14: Properties of Light
- 14.1 Light Dispersion and Rainbows
- 14.2 Lenses
- 14.3 Image Formation by a Lens
- 14.4 Diffraction—The Spreading of Light
- 14.5 Interference—Constructive and Destructive
- 14.6 Interference Colors by Reflection from Thin Films
- 14.7 Polarization—Evidence for the Transverse Wave Nature of Light
- 14.8 Wave-Particle Duality—Two Sides of the Same Coin
Chapter 15: The Atom
- 15.1 Discovering the Invisible Atom
- 15.2 Elements and the Periodic Table
- 15.3 The Atomic Nucleus Consists of Protons and Neutrons
- 15.4 Isotopes and Atomic Mass
- 15.5 Electron Shells—Regions About the Nucleus Where Electrons Are Located
Chapter 16: Nuclear Physics
- 16.1 Radioactivity—The Disintegration of the Atomic Nucleus
- 16.2 Alpha, Beta, and Gamma Rays
- 16.3 Environmental Radiation
- 16.4 Transmutation of Elements—Changing Identities
- 16.5 Half-Life Is a Measure of Radioactive Decay Rate
- 16.6 Isotopic Dating Measures the Ages of Materials
- 16.7 Nuclear Fission’The breaking Apart of Atomoic Nuclei
- 16.8 The Mass-Energy Relationship: E = mc2
- 16.9 Nuclear Fusion—The Combining of Atomic Nuclei
Chapter 17: Elements of Chemistry
- 17.1 Chemistry is Known as the Central Science
- 17.2 The Submicroscopic World is Super-Small
- 17.3 The Phase of Matter Can Change
- 17.4 Matter Has Physical and Chemical Properties
- 17.5 Determining Physical and Chemical Changes Can Be Difficult
- 17.6 The Periodic Table Helps Us to Understand the Elements
- 17.7 Elements Can Combine to From Compounds
- 17.8 There Is a System for Naming Compounds
Chapter 18: Bonds and Molecular Attractions
- 18.1 Electron-Dot Structures Help Us to Understand Bonding
- 18.2 Atoms Can Lose or Gain Atoms to Become Ions
- 18.3 Ionic Bonds Result from a Transfer of Electrons
- 18.4 Metal Atoms Bond by Losing Their Electrons
- 18.5 Covalent Bonds Result from a Sharing of Electrons
- 18.6 Electrons May Be Shared Unevenly in a Covalent Bond
- 18.7 Electrons Are Shared Unevenly in a Polar Molecule
- 18.8 Molecules Are Attractive
Chapter 19: How Chemicals Mix
- 19.1 Most Materials Are Mixtures
- 19.2 The Chemist’s Classification of Matter
- 19.3 A Solution Is a Single-Phase Homogenous Mixture
- 19.4 Concentration Is Given as Moles per Liter
- 19.5 Solubility Measures How Well a Solute Dissolves
- 19.6 Soap Works by Being Both Polar and Nonpolar
- 19.7 Purifying the Water We Drink
Chapter 20: How Chemicals React
- 20.1 Chemical Reactions Are Represented by Chemical Equations
- 20.2 Reaction Rates Can Be Slow or Fast
- 20.3 Catalysts Speed Up Chemical Reactions
- 20.4 Chemical Reactions Can Be Either Exothermic or Endothermic
- 20.5 Chemical Reactions Are Driven By Entropy
Chapter 21: Acids/Bases and Redox
- 21.1 Acids Donate and Bases Accept
- 21.2 Some Acids and Bases Are Stronger than Others
- 21.3 Solutions Can Be Acidic, Basic, or Neutrals
- 21.4 Rainwater Is Acidic and Ocean Water Is Basic
- 21.5 Oxidation Is the Loss of Electrons and Reduction Is the Gain of Electrons
- 21.6 The Energy of Flowing Electrons Can Be Harnessed
- 21.7 Oxygen Is Responsible for Corrosion and Combustion
- 21.8 Hydrogen Sulfide Can Induce Suspended Animation
Chapter 22: Organic Compounds
- 22.1 Hydrocarbons
- 22.2 Unsaturated Hydrocarbons
- 22.3 Functional Groups
- 22.4 Alcohols and Ethers
- 22.5 Amines and Alkaloids
- 22.6 Carbonyl Compounds
- 22.7 Polymers
Chapter 23: The Nutrients of Life
- 23.1 Biomolecules Are Molecules Produced and Used by Organisms
- 23.2 Carbohydrates Give Structure and Energy
- 23.3 Lipids Are Insoluble in Water
- 23.4 Proteins Are Polymerns of Amino Acids
- 23.5 Nucleic Acids Code for Proteins
- 23.6 Vitamins Are Organic, Minerals Are Inorganic
- 23.7 Metabolism Is the Cylcing of Biomolecules Through the Body
- 23.8 The Food Pyramid Summarizes a Healthful Diet
Chapter 24: Medicinal Chemistry
- 24.1 Medicines Are Drugs That Benefit the Body
- 24.2 The Lock-and-Key Model Guides Chemists in Creating New Medicines
- 24.3 Chemotherapy Cures the Host by Killing the Disease
- 24.4 The Nervous System Is a Network of Neurons
- 24.5 Psychoactive Drugs Alter the Mind or Behavior
- 24.6 Pain Relievers Inhibit the Transmission or Perception of Pain
Chapter 25: Rocks and Minerals
- 25.1 Our Rocky Planet
- 25.10 The Rock Cycle
- 25.2 What is a Mineral?
- 25.3 Mineral Properties
- 25.4 Classification of Rock-Forming Minerals
- 25.5 The Formation of Minerals and Rock
- 25.6 Rocks Are Divided Into Three Main Groups
- 25.7 Igneous Rocks Form When Magma Cools
- 25.8 Sedimentary Rocks Blanket Most of Earth’s Surface
- 25.9 Metamorphic Rocks Are Changed Rocks
Chapter 26: The Architecture of Earth
- 26.1 Earthquakes Make Seismic Waves
- 26.2 Seismic Waves Reveal Earth’s Internal Layers
- 26.3 Internal Motion Deforms Earth’s Surface
Chapter 27: Plate Tectonics
- 27.1 Continental Drift—An Idea Before its Time
- 27.2 Search For the Mechanism to Support Continental Drift
- 27.3 The Theory of Plate Tectonics
- 27.4 Three Types of Plate Boundaries
- 27.5 The Theory That Explains Much
Chapter 28: Shaping Earth's Surface
- 28.1 The Hydrologic Cycle
- 28.2 Groundwater—Water Below the Surface
- 28.3 The Work of Groundwater
- 28.4 Streams and Rivers—Water at Earth’s Surface
- 28.5 The Work of Surface Water
- 28.6 Glaciers and Glaciation—Earth’s Frozen Water
- 28.7 The Work of Glaciers
- 28.8 The Work of Air
Chapter 29: A Brief History of Earth
- 29.1 Relative Dating—The Placement of Rocks in Order
- 29.2 Radiometric Dating Reveals the Actual Time of Rock Formation
- 29.3 Geologic Time
- 29.4 Precambrian Time—A Time of Hidden Life
- 29.5 Paleozoic Era—A Time of Life Diversification
- 29.6 The Mesozoic Era—The Age of Reptiles
- 29.7 The Cenozoic Era—The Age of Mammals
- 29.8 Earth History in a Capsule
Chapter 30: The Oceans and Atmosphere
- 30.1 Earth’s Atmosphere and Oceans
- 30.2 Components of Earth’s Atmosphere
- 30.3 Solar Energy
- 30.4 Driving Forces of Air Motion
- 30.5 Global Atmospheric Circulation Patterns
- 30.6 Components of Earth’s Oceans
- 30.7 Oceanic Circulation
Chapter 31: Weather
- 31.1 Water in the Atmosphere
- 31.2 Weather Variables
- 31.3 There Are Many Different Clouds
- 31.4 Air Masses, Fronts, and Storms
- 31.5 Weather Can Be Violent
- 31.6 The Weather—Number One Topic of Conversatio
Chapter 32: The Solar System
- 32.1 The Solar System Is Mostly Empty Space
- 32.2 Solar Systems Form from Nebula
- 32.3 The Sun Is Our Prime Source of Energy
- 32.4 The Inner Planets Are Rocky
- 32.5 The Outer Planets Are Gaseous
- 32.6 Earth’s Moon
- 32.7 Failed Planet Formation
Chapter 33: Stars
- 33.1 Observing the Night Sky
- 33.2 Stars have Different Brightness and Color
- 33.3 The Hertzburg-Russell Diagram Describes Stars
- 33.4 The Life Cylce of Stars
- 33.5 Novae and Supernovae Are Stellar Explosions
- 33.6 Supergiant Stars Collapse into Black Holes
Chapter 34: Galaxies and the Cosmos
- 34.1 A Galaxy Is an Island of Stars
- 34.2 Elliptical, Spiral, and Irregular Galaxies
- 34.3 Active Galaxies Emit Huge Amounts of Energy
- 34.4 Galaxies Form Clusters and Superclusters
- 34.5 Galaxies Are Moving Away from One Another
- 34.6 Further Evidence for the Big Bang
- 34.7 Dark Matter is Invisible
- 34.8 Dark Energy Opposes Gravity