PHYSICAL SCIENCE CONCEPTS PHYSICAL SCIENCE CONCEPTS S E ECOND DITION Grant W. Mason Dana T. Griffen John J. Merrill James M. Thorne Editorial Assistance: Madlyn Tanner Illustrations: Rachel Adams, Jeff Michelsen, Lorraine Mullen Cover Design: Dave Eliason Cover Photograph: Brian Kelly Color Plates: Jeff Hester and Paul Scowen, Arizona State University, using the wide field and planetary camera 2 on board NASA’s Hubble Space Telescope on April 1, 1995 Layout Design: Bjorn Pendleton Figures Redesign: Joel Pullan, David Babcock, David Bentley, Bjorn Pendleton Copyright 1997 by the College of Physical and Mathematical Sciences, Brigham Young University All rights reserved. Published by Grant W. Mason Printed in the United States of America Brigham Young University Press ISBN 0-9611938-10-6 Contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiii Preface to the Second Edition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xv 1. Prologue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Authority Intuition Reason Sensory Data Self-Evident Truths Historical Perspectives: Plato, Aristotle, Aquinas, Copernicus, Galileo, Newton Study Guide: Fundamental Principles, Glossary, Exercises 2. Science and the Universe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 The World Around Us Nuclear Matter Atoms Molecules and Crystals Complexes of Molecules The Earth The Solar System The Milky Way Galaxy and Beyond Summary Historical Perspectives: The Emergence of Science Study Guide: Fundamental Principles, Glossary, Exercises THE SCIENCE OF MOTION 3. Laws Governing Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 The First Law of Motion Acceleration Force Mass The Second Law of Motion The Third Law of Motion Applications Summary Study Guide: Fundamental Principles, Glossary, Exercises 4. The Fundamental Interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 Falling Objects The Moon’s Orbit The Law of Universal Gravitation Some Simple Experiments with Electricity v The Electrical Model of Matter The Electric Force Law Electric Currents Electromagnetic Forces Applications Summary Study Guide: Fundamental Principles, Glossary, Exercises 5. Applications of the Laws of Force and Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 Gravitational Acceleration Forces within Matter Contact Forces Finding Forces Applications Involving More Than One Force Circular Motion The Nature of Scientific Laws Mechanistic Philosophy Applications Summary Study Guide: Fundamental Principles, Glossary, Exercises 6. Some Effects Due to Internal Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47 Forces within Solids Pressure Buoyant Forces Floating Objects Buoyancy in the Earth’s Crust: Isostasy Convection Summary Study Guide: Fundamental Principles, Glossary, Exercises 7. Conservation Laws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 Conservation of Mass Conservation of Electric Charge Conservation of Linear Momentum Conservation of Angular Momentum Forms of Energy Kinetic Energy Gravitational Potential Energy Electrical Potential Energy Internal Energy Conservation of Energy Energy Transfer and Transformation Processes Summary Historical Perspectives: Conservation of Energy Study Guide: Fundamental Principles, Glossary, Exercises 8. The Special Principle Relativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67 Motion Symmetry The Motion of the Earth Summary Historical Perspectives: The Motion of the Earth Study Guide: Fundamental Principles, Glossary, Exercises 9. Special Relativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 Spacetime vi Postulates of the Special Theory of Relativity Simultaneity Time Dilation Length Contraction Mass Increase Mass and Energy Summary Study Guide: Fundamental Principles, Glossary, Exercises THE SCIENCE OF MATTER 10. The Physical Properties of Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87 The Continuous Model of Matter The States of Matter Density Color Response to Force Electrical Properties Summary Study Guide: Fundamental Principles, Glossary, Exercises 11. The MolecularModel of Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 Molecules Brownian Motion The States of Matter Internal Energy and Temperature Heat Conduction Properties of Gases Change of Physical State Summary Historical Perspectives: Atoms and Molecules Study Guide: Fundamental Principles, Glossary, Exercises 12. The Law of Increasing Disorder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105 Irreversible Processes Order and Disorder Order and Energy Ways To Increase Order The “Energy” Crisis The Efficiency of Energy Conversion Pollution Equilibrium Summary Historical Perspectives: The Second Law of Thermodynamics and Materialism Study Guide: Fundamental Principles, Glossary, Exercises 13. Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115 Types of Waves Properties of Waves Wave Phenomena Reflection Refraction Diffraction Interference Summary Study Guide: Fundamental Principles, Glossary, Exercises vii 14. The Properties of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123 The Speed of Light The Source of Radiation The Electromagnetic Family Wave Phenomena of Light The Particulate Nature of Light Wave-Particle Duality Summary Historical Perspectives: What is Light? Study Guide: Fundamental Principles, Glossary, Exercises 15. The NuclearAtom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133 The Charged Particles in Atoms Electrons as Particles Mass Spectrometer The Rutherford Experiment The Bohr Model Discrete Spectra Continuous Spectra Summary Historical Perspectives: Rutherford and Bohr Discover the Nuclear Atom Study Guide: Fundamental Principles, Glossary, Exercises 16. Duality of Matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143 The Two-Slit Experiment Waves of Probability Electron Microscope The Uncertainty Principle What is Reality? The Role of the Newtonian Laws Summary Historical Perspectives: deBroglie and Davisson Discover the Electron Wave Study Guide: Fundamental Principles, Glossary, Exercises 17. The Wave Model of the Atom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155 Standing Waves Orbitals Energy Wells Orbital Energies Chemical Elements Summary Study Guide: Fundamental Principles, Glossary, Exercises 18. The Periodic Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .163 Periodic Patterns Historical Perspectives: The Emergence of Chemistry Study Guide: Fundamental Principles, Glossary, Exercises 19. Molecules and Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171 Molecular Structure Chemical Reactions Chemical Formulas Summary Study Guide: Fundamental Principles, Glossary, Exercises viii 20. Metals and theirCompounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .183 Pure Metals and Alloys Oxidation States Compounds Between Metals and Nonmetals Formulas and Names of Salts Summary Study Guide: Fundamental Principles, Glossary, Exercises 21. Compounds of Nonmetals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .193 Covalent Bonds Properties of Covalent Molecules Molecular Ions Minerals Summary Study Guide: Fundamental Principles, Glossary, Exercises 22. Chemistry of Living Things . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .201 Carbon Chains Functional Groups Proteins Nucleic Acids Summary Historical Perspectives: Mechanism versus Vitalism Study Guide: Fundamental Principles, Glossary, Exercises 23. How Life Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .215 How does the cell get its nutrients? How does the organism fabricate amino acids and nucleotides? How do the enzymes get energy to do their tasks? How does the cell make its proteins? How are the blueprints delivered to the ribosomes? How are the raw materials delivered to the ribosomes? How do the ribosomes execute the final assembly? How does the cell copy the blueprints before division? How do complex organisms develop? What are favorable conditions for life? Is life inevitable? Summary Study Guide: Fundamental Principles, Glossary, Exercises 24. The Nucleus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .223 Protons and Neutrons Radioactivity Alpha Decay Beta Decay Gamma Decay Electron Capture Positron Decay Fission Application of Radioactive Materials Radioactive Half-Life Radioactive Dating Summary Study Guide: Fundamental Principles, Glossary, Exercises ix 25. NuclearForces and NuclearEnergy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .233 The Strong Interaction Nuclear Energy Nuclear Fusion Nuclear Fission The Weak Interaction The Structure of Nucleons Summary Historical Perspectives: The Development of the Atomic Bomb Study Guide: Fundamental Principles, Glossary, Exercises MATTER IN MOTION 26. Cosmology: How the Universe Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .243 Measuring Astronomical Distances Measuring Motion The Expanding Universe Einstein’s General Relativity The Big Bang Universe APlausible Scenario for the Big Bang The Steady State Universe Summary Historical Perspectives: Is the Universe Infinite? Study Guide: Fundamental Principles, Glossary, Exercises 27. The History of a Star . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .255 From Dust to Star in 10 Million Years From Youth to Maturity in another 17 Million Years An Adult Life of 10 Billion Years The Star Becomes a Red Giant Death of a Small Star Death of a Massive Star Summary Historical Perspectives: What are the Stars? Study Guide: Fundamental Principles, Glossary, Exercises 28. Planet Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .263 The Solar System ABrief Tour of the Planets The Moon The Earth The Continents The Continental Shield The Stable Platform Fold Mountains Belts The Continents Reconsidered The Ocean Basins The Deep Ocean Floor The Oceanic Ridge Island Arcs and Other Island Chains The Oceans Reconsidered Summary Study Guide: Fundamental Principles, Glossary, Exercises x 29. Geologic Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .279 The Principles of Relative Dating Examples of Relative Dating The Geologic Column Absolute Time Uniformitarianism Early Estimates of the Age of the Earth Radiometric Dating The Geologic Column Revisited The Age of the Earth Summary Study Guide: Fundamental Principles, Glossary, Exercises 30. The Interiorof the Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .291 The Density of the Earth Seismic Waves and the Structure of the Earth The Composition of the Crust The Composition of the Mantle The Composition of the Core Summary of the Chemical Layering of the Earth—Differentiation The Mechanical Layering of the Earth Isostasy Summary Study Guide: Fundamental Principles, Glossary, Exercises 31. From Continental Drift to Plate Tectonics: The Evidence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .301 The Fit of the Continents Continental Structure Paleontological Evidence Paleoclimatic Evidence Paleomagnetic Evidence Wegner’s Hypothesis: Mechanism, Test, and Rejection Sea-Floor Spreading Magnetic Reversals and “Stripes” on the Seafloor Further Tests and Triumph The Breakup of Pangaea Postscript: AComment on the Way Science Works Summary Study Guide: Fundamental Principles, Glossary, Exercises 32. Plate Tectonics: AWorking Model forthe Earth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .315 Plate Motion Divergent Plate Boundaries Convergent Plate Boundaries Transform Boundaries Relative and Absolute Plate Motions—Hotspot Trails The Plate-Tectonic Evolution of a Continent Summary Study Guide: Fundamental Principles, Glossary, Exercises 33. Fossils: The Record of Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .327 The Significance of Fossils—AGradual Awakening Preservation of Fossils Complete Preservation Unaltered Hard Parts Replacement xi