sci321 prologue

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Science is the product of human curiosity about

how the world worksan organized body of

knowledge that describes the order within nature

and the causes of that order.Science is an ongoing

human activity that represents the collective

efforts, findings, and wisdom of the human race,

an activity that is dedicated to gathering knowl-

edge about the world and organizing and con-

densing it into testable laws and theories. In our

study of science,we are learning about the rules of

naturehow one thing is connected to another

and how patterns underlie all we see in our sur-

roundings. Any activity, whether a sports game,

computer game, or the game of life, is meaningful

only if we understand its rules. Learning aboutnatures rules is relevant with a capital R!

The beginnings of science go back before

recorded history, when people first discovered

repeating patterns in nature. They noted star

patterns in the night sky, patterns in the weather,

and patterns in animal migration. From these

the nature

of sci ence

prologue

A BRIEF H ISTORY OF ADVANCES IN SCIENCE

MATHEMATICS AND CONCEPTUALP HYSICAL SCIENCE

SCIENTIF IC METHODS

THE SCIENTIF IC ATTITUDE

SCIENCE HAS LIMITATIONS

S C I E N CE , A R T, A N D R E LI G I O N

TECHNOLOGYTHE P RACTICAL USE OF SCIENCE

THE P HYSICAL SCIENCES: P HYSICS, CHEMISTRY,EARTH SCIENCE, AND ASTRONOMY

IN P ERSP ECTIVE

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Conceptual Physical Science, Fourth Edition, by Paul G. Hewitt, John Suchocki, and Leslie A. Hewitt. Published by Addison-Wesley.Copyright 2008 by Pearson Education, Inc.


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2 PROLOGUE THE NATURE OF SCIENCE

patterns,people learned to make predictions that gave them

some control over their surroundings. Science is based on rational

thinking about the physical world.

A Brief History of Advances in Science

Science made great headway in Greece in the 4th and 3rd centuries BC andspread throughout the Mediterranean world. Scientific advance came to anear halt in Europe when the Roman Empire fell in the 5th centuryAD. Barbar-ian hordes destroyed almost everything in their paths as they overran Europe.Reason gave way to religion, which ushered in what came to be known as theDark Ages. During this time, the Chinese and Polynesians were charting the starsand the planets. Before the advent of Islam, Arab nations developed mathematicsand learned about the production of glass, paper, metals, and various chemicals.Greek science was reintroduced to Europe by Islamic influences that penetratedinto Spain during the 10th, 11th, and 12th centuries. Universities emerged inEurope in the 13th century, and the introduction of gunpowder changed thesocial and political structure of Europe in the 14th century. The 15th century sawart and science beautifully blended by Leonardo da Vinci. Scientific thought wasfurthered in the 16th century with the advent of the printing press.

The 16th-century Polish astronomer Nicolaus Copernicus caused great con-troversy when he published a book proposing that the Sun is stationary and thatEarth revolves around the Sun. These ideas conflicted with the popular viewthat Earth was the center of the universe. They also conflicted with Churchteachings and were banned for 200 years. The Italian physicist Galileo Galileiwas arrested for popularizing the Copernican theory and for his other contribu-tions to scientific thought. Yet a century later, those who advocated Copernicanideas were accepted.

These cycles occur age after age. In the early 1800s, geologists met with vio-lent condemnation because they differed with the account of creation in thebook of Genesis. Later in the same century, geology was accepted, but theoriesof evolution were condemned and the teaching of them was forbidden. Everyage has its groups of intellectual rebels who are scoffed at, condemned, andsometimes even persecuted at the time but who later seem beneficial and oftenessential to the elevation of human conditions. At every crossway on the roadthat leads to the future, each progressive spirit is opposed by a thousand menappointed to guard the past.*

Mathematics and Conceptual Physical Science

Science and human conditions advanced dramatically after science andmathematics became integrated some four centuries ago. When the ideasof science are expressed in mathematical terms, they are unambiguous. Theequations of science provide compact expressions of relationships between con-cepts. They dont have the multiple meanings that so often confuse the discus-sion of ideas expressed in common language. When findings in nature areexpressed mathematically, they are easier to verify or to disprove by experiment.

Science is a way of knowing aboutthe world and making sense of it.

* From Count Maurice Maeterlincks Our Social Duty.

Scientists have a deep-seated needto know Why? and What if?.

Mathematics is foremost in theirtoolkits for tackling these questions.

In pre-Copernican times theSun and Moon were viewedas planets.Their planetary statuswas removed when Copernicussubstituted the Sun for Earthscentral position. Only thenwas Earth regarded as a planetamong others. More than200

years later, in1781

, telescopeobservers added Uranus to thelist of planets. Neptune wasadded in 1846. Pluto was addedin 1930and removed in 2006.



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PROLOGUE THE NATURE OF SCIENCE 3

The mathematical structure of physics is evident in the many equations you willencounter throughout this book. The equations are guides to thinking thatshow the connections between concepts in nature. The methods of mathematicsand experimentation led to enormous success in science.*

Scientific Methods

There is no onescientific method. But there are common features in the wayscientists do their work. Although no cookbook description of thescientific method is really adequate, some or all of the following steps are likelyto be found in the way most scientists carry out their work.

1. Observe. Closely observe the physical world around you. Recognize a ques-tion or a puzzlesuch as an unexplained observation.

2. Question. Make an educated guessa hypothesisto answer the question.

3. Predict. Predict consequences that can be observed if the hypothesis is

correct. The consequences should be absentif the hypothesis is not correct.4. Test predictions. Do experiments to see if the consequences you predicted

are present.

5. Draw a conclusion. Formulate the simplest general rule that organizes thehypothesis, predicted effects, and experimental findings.

Although these steps are appealing, much progress in science has come fromtrial and error, experimentation without hypotheses, or just plain accidental dis-covery by a well-prepared mind. The success of science rests more on an attitudecommon to scientists than on a particular method. This attitude is one ofinquiry, experimentation, and humilitythat is, a willingness to admit error.

The Scientific Attitude

It is common to think of a fact as something that is unchanging and absolute.But in science, a factis generally a close agreement by competent observerswho make a series of observations about the same phenomenon. For example,although it was once a fact that the universe is unchanging and permanent, todayit is a fact that the universe is expanding and evolving. A scientific hypothesis, onthe other hand, is an educated guess that is only presumed to be factual until sup-ported by experiment. When a hypothesis has been tested over and over againand has not been contradicted, it may become known as a laworprinciple.

If a scientist finds evidence that contradicts a hypothesis, law, or principle, thescientific spirit requires that the hypothesis be changed or abandoned (unless thecontradicting evidence, upon testing, turns out to be wrongwhich sometimeshappens). For example, the greatly respected Greek philosopher Aristotle(384322 BC) claimed that an object falls at a speed proportional to its weight.This idea was held to be true for nearly 2000 years because of Aristotles com-pelling authority. Galileo allegedly showed the falseness of Aristotles claim with

* We distinguish between the mathematical structure of science and the practice of mathematicalproblem solvingthe focus of most nonconceptual courses. Note that there are fewer mathematicalproblems than exercises at the ends of the chapters in this book. The focus is on comprehensionbefore computation.

Science is a way to teach how some-thing gets to be known, what is notknown, to what extent things are

known (for nothing is knownabsolutely),how to handle doubtand uncertainty, what the rules of

evidence are, how to think aboutthings so that judgments can be

made, and how to distinguish truthfrom fraud and from show.

Richard Feynman

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one experimentdemonstrating that heavy and light objects dropped from theLeaning Tower of Pisa fell at nearly equal speeds. In the scientific spirit, a singleverifiable experiment to the contrary outweighs any authority, regardless of rep-utation or the number of followers or advocates. In modern science, argumentby appeal to authority has little value.*

Scientists must accept their experimental findings even when they would like

them to be different. They must strive to distinguish between what they see andwhat they wish to see, for scientists, like most people, have a vast capacity forfooling themselves.** People have always tended to adopt general rules, beliefs,creeds, ideas, and hypotheses without thoroughly questioning their validity andto retain them long after they have been shown to be meaningless, false, or atleast questionable. The most widespread assumptions are often the least ques-tioned. Most often, when an idea is adopted, particular attention is given tocases that seem to support it, while cases that seem to refute it are distorted,belittled, or ignored.

Scientists use the word theoryin a way that differs from its usage in everydayspeech. In everyday speech, a theory is no different from a hypothesisa sup-position that has not been verified. A scientific theory, on the other hand, is a

synthesis of a large body of information that encompasses well-tested andverified hypotheses about certain aspects of the natural world. Physicists, forexample, speak of the quark theory of the atomic nucleus, chemists speak of thetheory of metallic bonding in metals, and biologists speak of the cell theory.

The theories of science are not fixed; rather, they undergo change. Scientifictheories evolve as they go through stages of redefinition and refinement. Duringthe past hundred years, for example, the theory of the atom has been repeatedlyrefined as new evidence on atomic behavior has been gathered. Similarly,chemists have refined their view of the way molecules bond together, and biolo-gists have refined the cell theory. The refinement of theories is a strength ofscience, not a weakness. Many people feel that it is a sign of weakness to changetheir minds. Competent scientists must be experts at changing their minds. Theychange their minds, however, only when confronted with solid experimental evi-dence or when a conceptually simpler hypothesis forces them to a new point ofview. More important than defending beliefs is improving them. Better hypothe-ses are made by those who are honest in the face of experimental evidence.

Away from their profession, scientists are inherently no more honest or ethi-cal than most other people. But in their profession, they work in an arena thatplaces a high premium on honesty. The cardinal rule in science is that allhypotheses must be testablethey must be susceptible, at least in principle, tobeing shown to be wrong. Speculations that cannot be tested are regarded asunscientific. This has the long-run effect of compelling honestyfindingswidely publicized among fellow scientists are generally subjected to further test-ing. Sooner or later, mistakes (and deception) are found out; wishful thinking isexposed. A discredited scientist does not get a second chance in the communityof scientists. The penalty for fraud is professional excommunication. Honesty,so important to the progress of science, thus becomes a matter of self-interest toscientists. There is relatively little bluffing in a game in which all bets are called.In fields of study where right and wrong are not so easily established, the pres-sure to be honest is considerably less.


* But appeal to beautyhas value in science. More than one experimental result in modern times hascontradicted a lovely theory that, upon further investigation, proved to be wrong. This has bolsteredscientists faith that the ultimately correct description of nature involves conciseness of expressionand economy of conceptsa combination that deserves to be called beautiful.** In your education it is not enough to be aware that other people may try to fool you; it is moreimportant to be aware of your own tendency to fool yourself.

Before a theory is accepted, it mustbe tested by experiment and make

one or more new predictionsdifferent from those made by

previous theories.

Experiment, not philosophicaldiscussion, decides what is

correct in science.



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In science, it is more important to have a means of proving an idea wrongthan to have a means of proving it right. This is a major factor that distinguishesscience from nonscience. At first this may seem strange, for when we wonderabout most things, we concern ourselves with ways of finding out whether theyare true. Scientific hypotheses are different. In fact, if you want to distinguishwhether a hypothesis is scientific, look to see if there is a test for proving it

wrong. If there is no test for its possible wrongness, then the hypothesis is notscientific. Albert Einstein put it well when he stated, No number of experi-ments can prove me right; a single experiment can prove me wrong.

Consider the biologist Charles Darwins hypothesis that life forms evolvefrom simpler to more complex forms. This could be proven wrong if paleontol-ogists were to find that more complex forms of life appeared before their sim-pler counterparts. Einstein hypothesized that light is bent by gravity. This mightbe proven wrong if starlight that grazed the Sun and could be seen during a solareclipse were undeflected from its normal path. As it turns out, less complex lifeforms are found to precede their more complex counterparts and starlight isfound to bend as it passes close to the Sun, which support the claims. If andwhen a hypothesis or scientific claim is confirmed, it is regarded as useful and as

a stepping-stone to additional knowledge.Consider the hypothesis The alignment of planets in the sky determines thebest time for making decisions. Many people believe it, but this hypothesis isnot scientific. It cannot be proven wrong, nor can it be proven right. It is specu-lation. Likewise, the hypothesis Intelligent life exists on other planets some-where in the universe is not scientific. Although it can be proven correct by theverification of a single instance of intelligent life existing elsewhere in the uni-verse, there is no way to prove it wrong if no intelligent life is ever found. If wesearched the far reaches of the universe for eons and found no life, then thatwould not prove that it doesnt exist around the next corner. A hypothesis thatis capable of being proven right but not capable of being proven wrong is not ascientific hypothesis. Many such statements are quite reasonable and useful, butthey lie outside the domain of science.

C H E C KP O I N T

Which of these statements is a scientific hypothesis?(a) Atoms are the smallest particles of matter that exist.(b) Space is permeated with an essence that is undetectable.(c) Albert Einstein was the greatest physicist of the 20th century.

Was this your answer?

Only statement (a) is scientific,because there is a test for falseness.Thestatement not only is capable of being proven wrong,buthas beenproven wrong.Statement (b) has no test for possible wrongness and is

therefore unscientific. Likewise for any principle or concept for whichthere is no means, procedure,or test whereby it can be shown to bewrong (if it is wrong).Some pseudoscientists and other pretenders ofknowledge will not even consider a test for the possible wrongness oftheir statements. Statement (c) is an assertion that has no test for possi-ble wrongness.If Einstein was not the greatest physicist,how could weknow? Note that because the name Einstein is generally held in highesteem, it is a favorite of pseudoscientists. So we should not be surprisedthat the name of Einstein,like that of Jesus or of any other highlyrespected person, is cited often by charlatans who wish to bring respectto themselves and their points of view. In all fields,it is prudent to beskeptical of those who wish to credit themselves by calling upon theauthority of others.

The essence of science is expressedin two questions:How would we

know? What evidence would provethis idea wrong? Assertions withoutevidence are unscientific and can be

dismissed without evidence.

We each need a knowledge filtertotell the difference between what istrue and what only pretends to be

true.The best knowledge filter everinvented for explaining the physical

world is science.2008934301



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Science Has Limitations

Science deals only with hypotheses that are testable. Its domain is thereforerestricted to the observable natural world. Although scientific methods canbe used to debunk various paranormal claims, they have no way of accounting

for testimonies involving the supernatural. The term supernaturalliterally meansabove nature. Science works within nature, not above it. Likewise, science isunable to answer philosophical questions, such as What is the purpose of life?or religious questions, such as What is the nature of the human spirit? Thoughthese questions are valid and may have great importance to us, they rely onsubjective personal experience and do not lead to testable hypotheses. They lieoutside the realm of science.


Science and Society

Pseudoscience

For a claim to qualify as scientific, itmust meet certain standards. Forexample,the claim must be repro-

ducible by others who have no stake in

whether the claim is true or false.The

data and subsequent interpretations

are open to scrutiny in a social environ-

ment where its okay to have made an

honest mistake, but not okay to have

been dishonest or deceiving.Claims

that are presented as scientific but do

not meet these standards are what we

call pseudoscience, which literally

means fake science.In the realm of

pseudoscience,skepticism and tests

for possible wrongness are down-

played or flatly ignored.

Examples of pseudoscience abound.

Astrology is an ancient belief system

that supposes that a persons future is

determined by the positions and move-

ments of planets and other celestialbodies. Astrology mimics science in

that astrological predictions are based

on careful astronomical observations.

Yet astrology is not a science because

there is no validity to the claim that

the positions of celestial objects influ-

ence the events of a persons life.After

all, the gravitational force exerted by

celestial bodies on a person is smaller

than the gravitational force exerted by

objects making up the earthly environ-

ment: trees,chairs, other people, bars

of soap, and so on. Further, the predic-

tions of astrology are not borne out;

there just is no evidence that astrology

works.

For more examples of pseudo-

science, turn on the television.You can

find advertisements for a plethora of

pseudoscientific products. Watch out

for remedies to ailments such as

baldness,obesity, and cancer; for

air-purifying mechanisms;and for

germ-fightingcleaning products in

particular. Although many such prod-

ucts operate on solid science, others

are pure pseudoscience.Buyer beware!

Humans are very good at denial,

which may explain why pseudoscience

is such a thriving enterprise.Many

pseudoscientists do not recognize their

efforts as pseudoscience. A practitioner

of absent healing,for example, may

truly believe in her ability to cure peo-

ple she will never meet except throughe-mail and credit card exchanges.

She may even find anecdotal evi-

dence to support her contentions.The

placebo effect, discussed in Section8.2,

can mask the ineffectiveness of various

healing modalities. In terms of the

human body,what people believe will

happen often can happen because of

the physical connection between the

mind and body.

That said,consider the enormous

downside of pseudoscientific practices.

Today more than 20,000astrologers are

practicing in the United States. Do peo-

ple listen to these astrologers just for

the fun of it? Or do they base important

decisions on astrology? You might lose

money by listening to pseudoscientific

entrepreneurs;worse, you could

become ill. Delusional thinking,in gen-

eral,carries risk.

Meanwhile,the results of science

literacy tests given to the general pub-

lic show that most Americans lack a

basic understanding of basic concepts

of science.Some 63% of American

adults are unaware that the mass

extinction of the dinosaurs occurred

long before the first human evolved;

75% do not know that antibiotics kill

bacteria but not viruses;57% do not

know that electrons are smaller than

atoms.What we find is a rifta grow-

ing dividebetween those who have a

realistic sense of the capabilities of sci-ence and those who do not understand

the nature of science, its core concepts,

or, worse, feel that scientific knowledge

is too complex for them to understand.

Science is a powerful method for

understanding the physical world, and

a whole lot more reliable than pseudo-

science as a means for bettering the

human condition.



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Science, Art, and Religion

The search for a deeper understanding of the world around us has takendifferent forms, including science, art, and religion. Science is a systemby which we discover and record physical phenomena and think about pos-

sible explanations for such phenomena. The arts are concerned with personalinterpretation and creative expression. Religion addresses the source, purpose,and meaning of it all. Simply put, science asks how, art asks who, and religionasks why.

Science and the arts have certain things in common. In the art of literature,we find out about what is possible in human experience. We can learn aboutemotions such as rage and love, even if we havent yet experienced them. Thearts describe these experiences and suggest what may be possible for us. Simi-larly, a knowledge of science tells us what is possible in nature. Scientific knowl-edge helps us predict possibilities in nature even before we experience them. Itprovides us with a way of connecting things, of seeing relationships between andamong them, and of making sense of the great variety of natural events around

us. While art broadens our understanding of ourselves, science broadens ourunderstanding of our environment.Science and religion have similarities also. For example, both are motivated

by curiosity for the natural. Both have great impact on society. Science, forexample, leads to useful technological innovations, while religion provides afoothold for many social services. Science and religion, however, are basicallydifferent. Science is concerned with understanding the physical universe, whilereligion is concerned with spiritual matters, such as belief and faith. While sci-entific truth is a matter of public scrutiny, religion is a deeply personal matter.In these respects, science and religion are as different as apples and oranges anddo not contradict each other. Science, art, and religion can work very welltogether, which is why we should never feel forced into choosing one over the

other.That science and religion can work very well together deserves special empha-sis. When we study the nature of light later in this book, we treat light first as awave and then as a particle. At first, waves and particles may appear contradic-tory. You might believe that light can be only one or the other, and that youmust choose between them. What scientists have discovered, however, is thatlight waves and light particles complementeach other, and that when these twoideas are taken together, they provide a deeper understanding of light. In a sim-ilar way, it is mainly people who are either uninformed or misinformed aboutthe deeper natures of both science and religion who feel that they must choosebetween believing in religion and believing in science. Unless one has a shallowunderstanding of either or both, there is no contradiction in being religious in

ones belief system and being scientific in ones understanding of the naturalworld.*Many people are troubled about not knowing the answers to religious and

philosophical questions. Some avoid uncertainty by uncritically acceptingalmost any comforting answer. An important message in science, however, isthat uncertainty is acceptable. For example, in Chapter 15 youll learn that it isnot possible to know with certainty both the momentum and position of anelectron in an atom. The more you know about one, the less you can know

Art is about cosmic beauty. Scienceis about cosmic order. Religion is

about cosmic purpose.

* Of course, this does not apply to certain religious extremists who steadfastly assert that one cannotembrace both science and their brand of religion.

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about the other. Uncertainty is a part of the scientific process. Its okay not toknow the answers to fundamental questions. Why are apples gravitationallyattracted to Earth? Why do electrons repel one another? Why do magnets inter-act with other magnets? Why does energy have mass? At the deepest level, sci-entists dont know the answers to these questionsat least not yet. We know alot about where we are, but nothing really about whywe are. Its okay not to

know the answers to such religious questions. Given a choice between a closedmind with comforting answers and an open and exploring mind withoutanswers, most scientists choose the latter. Scientists in general are comfortablewith not knowing.

C H E C KP O I N T

Which of the following activities involves the utmost human expression ofpassion, talent, and intelligence? (a) painting and sculpture (b) literature(c) music (d) religion (e) science

Was this your answer?

All of them.In this book,we focus on science, which is an enchantinghuman activity shared by a wide variety of people. With present-day toolsand know-how, scientists are reaching further and finding out moreabout themselves and their environment than people in the past wereever able to do.The more you know about science, the more passionateyou feel toward your surroundings.There is science in everything you see,hear, smell, taste,and touch!

TechnologyThe Practical Use of Science

Science and technology are also different from each other. Science is con-cerned with gathering knowledge and organizing it. Technology lets

humans use that knowledge for practical purposes, and it provides the instru-ments scientists need to conduct their investigations.

Technology is a double-edged sword. It can be both helpful and harmful. Wehave the technology, for example, to extract fossil fuels from the ground andthen burn the fossil fuels to produce energy. Energy production from fossil fuelshas benefited society in countless ways. On the flip side, the burning of fossilfuels damages the environment. It is tempting to blame technology itself forsuch problems as pollution, resource depletion, and even overpopulation. Theseproblems, however, are not the fault of technology any more than a stabbing isthe fault of the knife. It is humans who use the technology, and humans who areresponsible for how it is used.

Remarkably, we already possess the technology to solve many environmentalproblems. The 21st century will likely see a switch from fossil fuels to moresustainable energy sources. We recycle waste products in new and better ways.In some parts of the world, progress is being made toward limiting humanpopulation growth, a serious threat that worsens almost every problem facedby humans today. Difficulty in solving todays problems results more fromsocial inertia than from failing technology. Technology is our tool. What we dowith this tool is up to us. The promise of technology is a cleaner and health-ier world. Wise applications of technology can improve conditions on planetEarth.


The belief that there is only onetruth and that oneself is in posses-

sion of it seems to me thedeepest root of all the evil that

is in the world.Max Born



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Risk Assessment

The numerous benefits of technologyare paired with risks. X-rays,forexample,continue to be used for med-ical diagnosis despite their potential

for causing cancer.But when the risks

of a technology are perceived to out-

weigh its benefits,it should be used

very sparingly or not at all.

Risk can vary for different groups.

Aspirin is useful for adults,but for

young children it can cause a poten-

tially lethal condition known as Reyes

syndrome. Dumping raw sewage into

the local river may pose little risk for a

town located upstream,but for towns

downstream the untreated sewageis a health hazard.Similarly, storing

radioactive wastes underground may

pose little risk for us today,but for

future generations the risks of such

storage are greater if there is leakage

into groundwater. Technologies involv-

ing different risks for different people,

as well as differing benefits,raise ques-

tions that are often hotly debated.

Which medications should be sold to

the general public over the counter

and how should they be labeled?

Should food be irradiated in order to

put an end to food poisoning,which

kills more than 5000Americans each

year? The risks to all members of soci-

ety need consideration when public

policies are decided.The risks of technology are not

always immediately apparent.No one

fully realized the dangers of combus-

tion products when petroleum was

selected as the fuel of choice for auto-

mobiles early in the last century. From

the hindsight of 20/20 vision, alcohols

from biomass would have been a supe-

rior choice environmentally,but they

were banned by the prohibition move-

ments of the day.

Because we are now more aware

of the environmental costs of fossil-fuel combustion, biomass fuels are

making a slow comeback. An aware-

ness of both the short-term risks and

the long-term risks of a technology

is crucial.

People seem to have a hard time

accepting the impossibility of zero risk.

Airplanes cannot be made perfectly

safe. Processed foods cannot be ren-

dered completely free of toxicity, for all

foods are toxic to some degree.You

cannot go to the beach without risking

skin cancer, no matter how much sun-

screen you apply. You cannot avoid

radioactivity, for its in the air you

breathe and the foods you eat,and it

has been that way since before

humans first walked on Earth.Even thecleanest rain contains radioactive

carbon-14, as do our bodies. Between

each heartbeat in each human body,

there have always been about 10,000

naturally occurring radioactive decays.

You might hide yourself in the hills, eat

the most natural foods,practice obses-

sive hygiene,and still die from cancer

caused by the radioactivity emanating

from your own body.The probability of

eventual death is 100%. Nobody is

exempt.

Science helps determine themost probable.As the tools of science

improve,then assessment of the most

probable gets closer to being on target.

Acceptance of risk,on the other hand,

is a societal issue.Placing zero risk as a

societal goal is not only impractical but

selfish. Any society striving toward a

policy of zero risk would consume

its present and future economic

resources. Isnt it more noble to accept

nonzero risk and to minimize risk as

much as possible within the limits of

practicality? A society that accepts no

risks receives no benefits.

The Physical Sciences: Physics,Chemistry,Earth Science, and Astronomy

Science is the present-day equivalent of what used to be called natural phi-losophy. Natural philosophy was the study of unanswered questions aboutnature. As the answers were found, they became part of what is now called sci-ence. The study of science today branches into the study of living things andnonliving things: the life sciences and the physical sciences. The life sciencesbranch into such areas as molecular biology, microbiology, and ecology. Thephysical sciencesbranch into such areas as physics, chemistry, the Earth sciences,and astronomy.

A few words of explanation about each of the major divisions of science:Physics is the study of such concepts as motion, force, energy, matter, heat, sound,light, and the components of atoms. Chemistry builds on physics by telling ushow matter is put together, how atoms combine to form molecules, and how themolecules combine to make the materials around us. Physics and chemistry,applied to Earth and its processes, make up Earth sciencegeology, meteorology,

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and oceanography. When we apply physics, chemistry, and geology to other plan-ets and to the stars, we are speaking about astronomy. Biology is more complexthan physical science, for it involves matter that is alive. Underlying biology ischemistry, and underlying chemistry is physics. So physics is basic to both physi-cal science and life science. That is why we begin with physics, then follow withchemistry, then investigate Earth science and conclude with astronomy. All are

treated conceptually, with the twin goals of enjoyment and understanding.

In Perspective

Just as you cant enjoy a ball game, computer game, or party game until youknow its rules, so it is with nature. Because science helps us learn the rules ofnature, it also helps us appreciate nature. You may see beauty in a structure suchas the Golden Gate Bridge, but youll see more beauty in that structure when youunderstand how all the forces that act on it balance. Similarly, when you look atthe stars, your sense of their beauty is enhanced if you know how stars are bornfrom mere clouds of gas and dustwith a little help from the laws of physics, ofcourse. And how much richer it is, when you look at the myriad objects in yourenvironment, to know that they are all composed of atomsamazing, ancient,invisible systems of particles regulated by an eminently knowable set of laws.

If the complexity of science intimidates you, bear this in mind: All thebranches of science rest upon a relatively small number of basic rules. Learnthese underlying rules (physical laws), and you have a tool kit to bring to anyphenomenon you wish to understand.

Go to itwe live in a time of rapid and fascinating scientific discovery!


S U M M A R Y O F T E R M S

Science The collective findings of humans about nature, and aprocess of gathering and organizing knowledge aboutnature.

Scientific method Principles and procedures for the system-atic pursuit of knowledge involving recognition andformulation of a problem, collection of data throughobservation and experiment, and formulation and testingof hypotheses.

HypothesisAn educated guess; a reasonable explanation of anobservation or experimental result that is not fully acceptedas factual until tested over and over again by experiment.

FactA phenomenon about which competent observers whohave made a series of observations agree.

LawA general hypothesis or statement about the relationshipof natural quantities that has been tested over and overagain and has not been contradicted. Also known as aprinciple.

TheoryA synthesis of a large body of information thatencompasses well-tested and verified hypotheses aboutcertain aspects of the natural world.

Pseudoscience Fake science that pretends to be realscience.

R E V I E W Q U E S T I O N S

1. Briefly, what is science?

A Brief History of Advances in Science

2. Throughout the ages, what has been the general reactionto new ideas about established truths?

Mathematics and Conceptual Physical Science

3. What is the role of equations in this course?

Scientific Methods

4. Outline the steps of the classic scientific method.



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The Scientific Attitude

5. Distinguish between a scientific fact, a hypothesis, a law,and a theory.

6. In daily life, people are often praised for maintainingsome particular point of view, for the courage of theirconvictions. A change of mind is seen as a sign of

weakness. How is this different in science?7. What is the test for whether a hypothesis is scientific

or not?8. In daily life, we see many cases of people who are caught

misrepresenting things and who soon thereafter areexcused and accepted by their contemporaries. How isthis different in science?

Science Has Limitations

9. What is meant by the term supernatural?

Science, Art, and Religion

10. Why are students of the arts encouraged to learn

about science and science students encouraged tolearn about the arts?

11. Why do many people believe they must choose betweenscience and religion?

12. Psychological comfort is a benefit of having solid answersto religious questions. What benefit accompanies a posi-tion of not knowing the answers?

TechnologyThe Practical Use of Science

13. Clearly distinguish between science and technology.

The Physical Sciences:Physics,Chemistry, EarthScience, and Astronomy

14. Why is physics considered to be the basic science?

In Perspective

15. What is the importance to you in learning natures rules?

E X P L O R I N G F U R T H E R

Bodanis, David. A Biography of the WorldsMost Famous Equation. New York: Berkley PublishingGroup, 2002. This is an engaging book about the peopleof science.

Bryson, Bill.A Short History of Nearly Everything. NewYork: Broadway Books, 2003. Another engaging bookabout the people of science, and from time to time, theirzany antics.

E = mc2: Feynman, Richard P. Surely Youre Joking, Mr. Feynman.New York: Norton, 1986. This is such tasty reading that I(PGH) allowed myself only one chapter per reading!

Gleick, James. GeniusThe Life and Science of RichardFeynman. New York: Pantheon Books, 1992. More indepth about perhaps the most colorful physicist of the20th century.

E X E R C I S E S

1. Which of the following are scientific hypotheses?(a) Chlorophyll makes grass green. (b) Earth rotates aboutits axis because living things need an alternation of lightand darkness. (c) Tides are caused by the Moon.

2. In answer to the question, When a plant grows, wheredoes the material come from?, Aristotle hypothesized by

logic that all material came from the soil. Do you con-sider his hypothesis correct, incorrect, or partially correct?What experiments do you propose to support yourchoice?

3. The great philosopher and mathematician BertrandRussell (18721970) wrote about ideas in the early partof his life that he rejected in the latter part of his life. Doyou see this as a sign of weakness or as a sign of strength

in Bertrand Russell? (Do you speculate that your presentideas about the world around you will change as you learnand experience more, or do you speculate that furtherknowledge and experience will solidify your presentunderstanding?)

4. Bertrand Russell wrote, I think we must retain the belief

that scientific knowledge is one of the glories of man.I will not maintain that knowledge can never do harm.I think such general propositions can almost always berefuted by well-chosen examples. What I will maintainand maintain vigorouslyis that knowledge is very muchmore often useful than harmful and that fear of knowl-edge is very much more often harmful than useful.Think of examples to support this statement.

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