Physical Science in the Modern World

710 Pages·1974·35.937 MB·English

by  Jerry Marion (Auth.)

in the
modern
world
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Library of Congress Cataloging in Publication Data
Marion, Jerry B
Physical science in the modern world.
1. Science. I. Title.
Q161.2.M37 500.2 73-5310
ISBN 0-12-472260-1
PRINTED IN THE UNITED STATES OF AMERICA
In addition to the acknowledgments expressed in the credit lines accompanying photographs in the text, permis-
sion to reproduce illustrations on the following pages from the sources listed is gratefully acknowledged: 25,
Harbrace; 55, C. F. Powell, P. H. Fowler, D. H. Perkins (eds.), The Study of Elementary Particles by the Pho-
tographic Method (Pergamon Press, Oxford, 1959); 73, British Crown Copyright, Science Museum London;
80, Lawrence H. Aller, Atoms, Stars, and Nebulae, Rev. Ed. (Harvard University Press, Cambridge, Mass., 1971);
84, A. C. van Heel and C. H. F. Velzel, What Is Light (McGraw-Hill, New York, 1968); 98, 199, Gordon
Newkirk, High Altitude Observatory, Boulder Colorado; 152, M. R. Cambell, USGS; 159, West Virginia Cham-
ber of Commerce; 170, R. H. Dott and R. L. Batten, Evolution of the Earth (McGraw-Hill, New York, 1971);
203, High Altitude Observatory; 271, (1) AIP, E. C. Goddard, (2) Tass, Sovfoto, (3) NASA; 318, Pacific Gas
and Electric; 328, J. N. Pitts and R. L. Metcalf, Advances in Environmental Sciences, Vol. I (Wiley, New York,
1969); 357, The University of Maryland, Richard Farkas; 376, General Electric; 405, Winchester-Western; 393,
410, 411, J. B. Marion, Physics and the Physical Universe (Wiley, New York, 1971) and EDC; 460, 472,
AEC, Lotte Jacobi; 481, F. W. Sears, Optics (Addison-Wesley, Reading, Massachusetts, 1949); 483, Harbrace;
508, lent to Science Museum London by Sir Lawrence Bragg, F. R. S; 519, Hughes Aircraft; 547, G. L. Lee,
H. O. Van Orden, and R. O. Ragsdale, General and Inorganic Chemistry (Saunders, Philadelphia, 1971); 544,
Pratt and Whitney; 632, UKAEA. Figures 6-2 (121) and 19-18 (438) are adapted from A. N. Strahler, Physical
Geography (Wiley, New York, 1969).
Preface
Science is a fascinating subject. Surely, almost everyone has wondered, at
one time or another, about the origin of the Universe, about the nature of
life, about the way electricity works, or why the weather behaves the way
it does. Behind the complex and varied facade of Nature we find a beau-
tifully ordered design. From the tiniest bits of matter to the enormity of the
Universe there exists a structure that is based on a surprisingly small
number of far-reaching fundamental principles. The physical effect that
acts to maintain the Earth in its orbit around the Sun is the same that
causes a dropped coin to fall to the floor. The surge of electricity that
results in a gigantic stroke of lightning is the same (on a much vaster scale)
as the flow of electricity that operates a transistor radio. And the molecules
of life within every living thing are held together by the same force that
causes a shock when you shuffle across a carpet and touch a door knob.
In this book we will survey the whole range of the physical (or non-
biological) sciences. We will discuss some of the crucial ideas and concepts
in physics, chemistry, astronomy, geology, and meteorology. We will see
how these sciences bear strongly upon one another and how the basic
physical principles are applied to each. In so doing, we will not neglect the
way in which science most directly affects our everyday lives —namely,
through modern technology. Scattered throughout the following pages will
be found numerous sections devoted to explanations of devices that im-
pinge directly or indirectly on the way we live.
The physical sciences at one time stood distinct and apart from the life
sciences. This is no longer true. Although in this book we do not deal
specifically with the biological aspects of Nature, we shall from time to
time point out important biological effects that stem from the basic physical
Xlll
laws. Probably the most important single impression that the reader can
carry away from a study of the material in this book is an appreciation for
the unity of science.
This book is divided into three roughly equal parts. Part I presents a
description of the grand sweep of Nature —from atoms to the cosmos. We
begin by looking at the fundamental building blocks of matter and how they
are assembled to form molecules, minerals, rocks, and finally the Earth it-
self. We describe the important features of light and how we use this tool to
examine the planets, the Sun, the stars, and the distant galaxies. Some of
the readers of this book may never have felt particularly comfortable with
science. Especially for them, Part I represents a nonmathematical look at
the Universe as a whole. Some appreciation for the physical sciences can
therefore be gained before we launch into more-detailed examinations of
physical subjects.
In Part II we take a closer look at the basic concepts of physical science.
Here we learn about the fundamental principles that govern all physical
processes and we see how they relate to many everyday occurrences. One
of the key ideas in science is that of energy. We will see how widely useful
this concept really is. We also examine the way in which energy affects our
day-to-day life in the form of the "energy crisis." In this discussion we see
the impact of geology upon modern society and how many facets of our fu-
ture depend upon the way in which the Earth's crust is put together.
In Part III we concern ourselves with the contemporary ideas of science
and technology. We will learn about the way in which Albert Einstein
forced us to change our notions about space and time. We will look at how
modern chemistry affects the world we live in and how the development of
semiconductor materials has ushered in a new age of miniature electronics.
We will discuss the operation of nuclear power reactors and we will exam-
ine the ways in which nuclear radiations are used by and how they affect
mankind. Finally, we draw upon many topics we have developed to under-
stand something about the formation and evolution of stars and the history
of the Universe.
An effort has been made to present each subject clearly and carefully.
But even more important, the aim in preparing this book has been to show
that science is a human activity whose goal is to understand the wonder
and the mystery and the magnificence of the Universe around us.
College Park, Maryland JERRY B. MARION
o
Introduction to physical science
From his home on the Earth, Man can look through a telescope into the
vast reaches of space. Or he can look through a microscope into the minia-
ture world of cells and molecules. The scale of things that Man has been
able to observe and study truly staggers the imagination. Roughly speaking,
the Universe is as many times larger than the Earth as the Earth is larger
than an atom. Thus, Man stands in a middle position, privileged to view
the immensely large Universe populated with an incalculable number of
stars and galaxies as well as the microscopic domain of incredibly tiny
atoms and molecules. As wonderful as this accomplishment is, it becomes
even more remarkable when we realize that, despite the fact that Man can
neither touch the stars nor handle individual atoms, he has been able to
learn the behavior of both the large and the small of the Universe.
Some of the most fascinating discoveries made in this century have con-
cerned the structure and the evolution of the Universe and the structure
and behavior of molecules, atoms, and nuclei, the ultimate pieces of matter.
As we have plumbed the depths of space, we have come to realize how
insignificant a speck of dust our Earth actually is. We have long ago ceased
to consider the Earth as the center of the Universe. And now we know that
the Sun and its collection of planets is not even a central feature of the
local collection of stars, the Milky Way. Nor does our home galaxy inhabit
any special part of the Universe. Indeed, the Earth is quite unremark-
able—an average planet revolving around an average star located in the
periphery of an average galaxy that is lost among the uncounted galaxies of
the Universe.
While Man has looked outward at the stars, he has also looked inward at
the constituents of the matter that makes up his world. He has discovered
the way in which atoms bind together to form molecules and the way in
which clusters of molecules form bulk matter. He has discovered the elec-
trical nature of matter and he has probed deep within the atom to study the
1
behavior of the nuclear core. He has even vestigations of the interrelationships among
found a way to tap the nuclear energy supply people. The social sciences are distinguished
and apply it to his own needs. from the physical and biological sciences in
Man has reached out from his position that only very general explanations can be of-
between the large and the small of the Uni- fered for human group behavior, whereas the
verse and he has uncovered at least some of functioning of physical and (at least the more
the rules by which Nature governs the micro- elementary) biological systems takes place in
scopic (or small-scale) world of atoms and the an orderly fashion subject to precise natural
macroscopic (or large-scale) realm of the laws. Moreover, it is difficult to perform con-
stars. In this book we will examine some of trolled experiments in the social fields be-
the physical features of the Universe and we cause the situations are extremely complex,
whereas this technique is at the heart of phys-
will see the way in which the laws of Nature
ical and biological investigations. These facts
influence physical phenomena in various do-
do not imply that the social sciences are less
mains.
important than the physical and biological
sciences (indeed, they are perhaps more im-
/-/ Studying the world around us portant), but only that the social sciences
cannot yet be discussed in the same scientific
PHYSICAL SCIENCE terms as can the natural sciences.
Scientific studies can be divided into two Within the general area of the physical sci-
ences we can identify a number of separate
large and general categories: the biological
disciplines such as physics, astronomy, chem-
sciences (dealing with living things and pro-
istry, geology, and meteorology. These sub-
cesses) and the physical sciences (dealing
jects were once isolated fields of study but,
with inanimate things and processes). These
more and more, attention is being focused on
categories are not completely separate and
areas in which two or more of these fields
distinct, and although we will be concerned in
overlap. We thus find the relatively new sub-
this book primarily with the physical aspects
ject areas of biophysics, geochemistry, and
of the Universe, from time to time we will
exobiology (the study of life in space). Some
discuss the relationship between some physi-
of the disciplines of modern science and their
cal phenomenon and a biological process. All
interrelationships are shown in Fig. 1-1.
matter — living as well as nonliving — is com-
Physics is placed in the central position in
posed of the same basic ingredients, namely,
this diagram because it deals with the basic
atoms and molecules. The natural laws that
laws governing the most fundamental natural
govern the behavior of atoms and molecules
processes. Physics therefore has a direct link
in inanimate objects also regulate the actions
to most of the other physical sciences that
of atoms and molecules in living things.
deal with more complex systems. Modern
Therefore, on the most fundamental level, the
technology, engineering, and computer sci-
distinction between physical and biological
ences provide the technical back-up without
processes disappears. Most of our discus-
which many investigations in these various
sions of biological processes will be con-
fields could not be carried out.
cerned with the molecular aspects of the sub-
ject so that we can draw upon our knowledge
WHAT GOOD IS SCIENCE?
of physical phenomena for their interpreta-
tion. We live in a technological society. Almost
Another broad category of study and re- every aspect of life in the modern world is
search is that of the social sciences. In this influenced (for better or for worse) by our
field, scientific techniques are applied to in- technological surroundings. Communications,
2 / Introduction to physical science
transportation, manufacturing, mining and we can appreciate the role that technology
exploration, the service industries, medicine, plays in modern society. For without some
agriculture —all are dominated by methods knowledge of the scientific principles by
and apparatus which are the result of tech- which technology operates, one can neither
nological advances. The basis of technology cope with technology nor assist in directing it
is science. Without the fundamental discover- into the proper channels.
ies and understanding provided by science, In recent times, we have had the general
technology would be a hit-or-miss affair, attitude that whatever is technologically pos-
lacking direction and making little progress. sible should be done. It is now becoming
One can argue that our society is beginning increasingly apparent that our scientific and
to suffer from too much technology, but we technological progress has outstripped our
will never (short of a nuclear holocaust) re- capacity to perform or absorb everything that
turn to the primitive life of our forefa- is possible. More and more, we will have
thers—technology is with us and it will re- decisions to make: in what directions should
main with us. the thrust of our new discoveries be made?
Just as it is important to study history so The situation requires that we make in-
that we can appreciate how the world came telligent decisions —decisions based on a
to its present state, it is important to learn knowledge and an understanding of what can
some of the basic concepts of science so that be done, what will be the benefits, and what
Hale Observatories
The large and the small of the Universe. On the left is a telescopic pho-
tograph of the Andromeda galaxy and on the right is a microscopic pho-
tograph of a paramecium, a one-celled animal. The diameter of Androm-
eda is approximately 1 000 000 000 000 000 000 000 m (1021 m)
whereas the size of the paramecium is approximately 0,0001 m (10~4 m).
1-1 Studying the world around us 3
Figure 1-1 The interrelationships among some of the more prominent areas
of modern science. Only the major linkages are shown.
will be the consequences. Scientists do not To understand the basis of technology is
make these decisions— people make them. It not the only reason for learning about sci-
is therefore incumbent on every individual to ence. We study art and music and philosophy
acquire the basic knowledge that will permit so that we can appreciate a great painting or a
him to participate intelligently in directing the majestic symphony or a particular view of
course of our technological advancement. life. There is intellectual satisfaction in these
4 1 Introduction to physical science
pursuits and they enrich our lives. Science meaning of terms such as one quart or one
too is beautiful and enriching. How dull life acre or one hour, it will be impossible to give
would be if we were to cease to wonder about a precise interpretation to any measurement.
the world around us and to try to understand The necessity for standards of various kinds
the way in which Nature behaves. has given rise to an enormous number of
measuring units, many of which apply to the
same physical quantity. (See, for example,
the list of volume units below.) Many of
1-2 Describing and measuring things
these measuring units have very specialized
applications —for example, the tablespoon in
THE BASIC CONCEPTS
cooking or the rod in surveying or the caret
Progress is made in understanding our physi- in gemmology. Fortunately, in scientific
cal surroundings through observation and matters a restricted set of measuring units is
measurement coupled with logic and reason. used.
In order to describe our observations and to
record our measurements, we must agree on
the language and the terms that we will use. Some units of volume in common
Our intuitive ideas concerning physical con- American usage
cepts will serve as the starting points for most
Pint Gill
of our discussions of the world around us.
Quart Peck
One of the important aspects of measure-
Gallon Bushel
ments of any type is the existence of a set of
Fluid Ounce Barrel
standards. Unless we all agree on the
Dram Acre-foot
Cup Fifth
Teaspoon Magnum
It will require many years for the United Tablespoon Jeroboam
States to change to the metric system, but Hogshead
evidence that the conversion is underway is
beginning to appear. (Plus the cube of any of the units of
length: ft3, yd3, mi3, and so on.)
UPI
The fundamental units of measure in sci-
ence are those of length, time, and mass.
These are familiar concepts, but because
they are so basic to the description of phys-
ical events and phenomena, we will briefly
discuss each of these units in turn.
LENGTH
Most Americans are accustomed to mea-
suring distance in terms of inches, feet, yards,
and miles —the so-called British system of
units. These length units are derived from a
variety of sources, dating back hundreds or
thousands of years to periods when there
1-2 Describing and measuring things 5
Table 1-1 Metric Units of Length 100 000 000, almost a hundred times better
than was previously possible.
10 mm = 1 cm
The metric system has the advantage (not
100 cm = 1 m
shared by the British system) that the various
1000 m= 1 km
units of a physical quantity are related by
factors of 10, thus considerably simplifying
any manipulations that are necessary. For ex-
ample,
were only the crudest of standards for the
measurement of length. Today, the scientific 1 m =100 centimeters (cm), or 102 cm
community universally uses the metric
1 cm = 0.01 m, or 10"2 m
system of measure. Indeed, even for every-
day matters, most of the world (with the pri- 1 m =0.001 kilometer (km), or 10"3 km
mary exception of the United States) uses
1 km= 1000 m, or 103 m
metric measure. In order to preserve our po-
sition in world trade, the United States will The metric units of length are summarized in
eventually change over from its archaic Table 1-1.
system to metric units. But it will probably be Here we use a shorthand notation for ex-
many years until we will have foregone com- pressing large and small numbers —the
pletely our present system. powers-of-ten notation. For example,
The standard of length in the metric system
is the meter (m). Compared to the length 100= 102 1 = 0.01 = 10"2
100
units in the British system, the meter has the 1000= 103
following values: 1
1 000 000= 106 = 0.001 = 103
1000
1 m = 39.37 in. = 3.281 ft = 1.094 yd
1
That is, a meter is about 10 percent longer = 0.000001 = 10~6
1000 000
than a yard.
Until 1961 the meter was defined as the We can use this notation to express
distance between two finely drawn lines on a numbers in the following ways:
certain metal bar housed in the International
3 260 = 3.26xl03
Bureau of Weights and Measures, near Paris.
Copies of this bar were distributed to national 4 100 000 = 4.1 X 106
standards laboratories throughout the world.
However, in 1961 an international agreement 98 000 000 = 0.98 X 108
was made to define the meter in terms of the 0.023 = 2.3 x 10-2
wavelength of the orange light emitted by
krypton gas. Thus, we now have an atomic 0.000 017= 1.7 x 10"5
standard for length. Because all atoms of 0.000 009 = 0.9 x 10"5
krypton are exactly alike, a length standard
can be established in any laboratory where it Occasionally, we will need to convert from
is required, and it is guaranteed that all such
krypton standards will be absolutely iden-
tical. Not only does the adoption of an atomic Table 1-2 Length Conversion Factors
standard for length eliminate the necessity
of relying on the inconvenient standard me- 2.54 cm = 1 in.
ter bar, but now it is possible to intercom- 39.37 in. = 1 m
pare lengths to a precision of 1 part in 1.609 km = 1 mi
6 / Introduction to physical science