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Preface
Why a New Physics Textbook.
We assume that our economic system will always scamper to provide us with the products we want. Special
orders don’t upset us! I want my MTV! The truth is more complicated, especially in our education system, which
is paid for by the students but controlled by the professoriate. Witness the perverse success of the bloated science
textbook. The newspapers continue to compare our system unfavorably to Japanese and European education,
where depth is emphasized over breadth, but we can’t seem to create a physics textbook that covers a manageable
number of topics for a one-year course and gives honest explanations of everything it touches on.
The publishers try to please everybody by including every imaginable topic in the book, but end up pleasing
nobody. There is wide agreement among physics teachers that the traditional one-year introductory textbooks
cannot in fact be taught in one year. One cannot surgically remove enough material and still gracefully navigate
the rest of one of these kitchen-sink textbooks. What is far worse is that the books are so crammed with topics that
nearly all the explanation is cut out in order to keep the page count below 1100. Vital concepts like energy are
introduced abruptly with an equation, like a first-date kiss that comes before “hello.”
The movement to reform physics texts is steaming ahead, but despite excellent books such as Hewitt’s Concep-
tual Physics for non-science majors and Knight’s Physics: A Contemporary Perspective for students who know
calculus, there has been a gap in physics books for life-science majors who haven't learned calculus or are learning
it concurrently with physics. This book is meant to fill that gap.
Learning to Hate Physics.
When you read a mystery novel, you know in advance what structure to expect: a crime, some detective work,
and finally the unmasking of the evildoer. When Charlie Parker plays a blues, your ear expects to hear certain
landmarks of the form regardless of how wild some of his notes are. Surveys of physics students usually show that
they have worse attitudes about the subject after instruction than before, and their comments often boil down to a
complaint that the person who strung the topics together had not learned what Agatha Christie and Charlie Parker
knew intuitively about form and structure: students become bored and demoralized because the “march through
the topics” lacks a coherent story line. You are reading the first volume of the Light and Matter series of introduc-
tory physics textbooks, and as implied by its title, the story line of the series is built around light and matter: how
they behave, how they are different from each other, and, at the end of the story, how they turn out to be similar
in some very bizarre ways. Here is a guide to the structure of the one-year course presented in this series:
1 Newtonian PhysicsMatter moves at constant speed in a straight line unless a force acts on it. (This seems
intuitively wrong only because we tend to forget the role of friction forces.) Material objects can exert forces on
each other, each changing the other’s motion. A more massive object changes its motion more slowly in re-
sponse to a given force.
2 Conservation LawsNewton’s matter-and-forces picture of the universe is fine as far as it goes, but it doesn’t
apply to light, which is a form of pure energy without mass. A more powerful world-view, applying equally well
to both light and matter, is provided by the conservation laws, for instance the law of conservation of energy,
which states that energy can never be destroyed or created but only changed from one form into another.
3 Vibrations and WavesLight is a wave. We learn how waves travel through space, pass through each other,
speed up, slow down, and are reflected.
4 Electricity and MagnetismMatter is made out of particles such as electrons and protons, which are held
together by electrical forces. Light is a wave that is made out of patterns of electric and magnetic force.
5 OpticsDevices such as eyeglasses and searchlights use matter (lenses and mirrors) to manipulate light.
6 The Modern Revolution in PhysicsUntil the twentieth century, physicists thought that matter was made
out of particles and light was purely a wave phenomenon. We now know that both light and matter are made of
building blocks that have both particle and wave properties. In the process of understanding this apparent
contradiction, we find that the universe is a much stranger place than Newton had ever imagined, and also learn
the basis for such devices as lasers and computer chips.