conceptual physics fundamentals - srjcsrjcstaff.santarosa.edu/~alee3/physics 11/powerpoint...

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Addison-Wesley

Conceptual Physics

Fundamentals

Chapter 1:

ABOUT SCIENCE


This lecture will help you

understand:

• Science

• Mathematics—The Language of Science

• Scientific Measurements

• Scientific Methods

• The Scientific Attitude

• Science, Art, and Religion

• Science and Technology

• Physics—The Basic Science


Science

Science

• is a body of knowledge

• is an ongoing human activity

• has beginnings that precede recorded history


Astronomy

•1500 BC- Stonehenge used to track the sun and mark the solstice

•1200 BC- Babylonians study 'astrology' & invent the 12 signs used today

•280 BC- Aristarchus (Greek) stated that the Sun was the center of the 'solar

system'. It was almost 1800 yrs later that his theory would be widely accepted.

Early man studied the moon & the sun to learn when to sow their crops and when

to harvest. We still use this method to this day.


Invention of the Wheel

• It is still a mystery as to who invented the wheel and

when the wheel was invented.

• According to archaeologists, it was probably invented

in around 8,000 B.C. in Asia.

• The oldest wheel known however, was discovered in

Mesopotamia and probably dates back to 3,500 B.C.


Science


Mathematics—The Language of Science

Integration of science and mathematics

• occurred some four centuries ago

• ideas of science are unambiguous when

expressed in mathematical terms

• equations of science provide expressions of

relationships between concepts

• equations are “guides to thinking”


Early Mathematics

• 1800 BC – Babylonian clay

tablets cover topics which

include fractions, algebra,

quadratic and cubic

equation

• Babylonian mathematics

were written using a base-

60 numeral system. This

derives the modern day

usage of 60 seconds in a

minute, 60 minutes in an

hour, and 360 (60 x 6)

degrees in a circle.


Algebra

• The word algebra is a Latin variant of the Arabic

word al-jabr. This came from the title of a book,

Hidab al-jabr wal-muqubala, written in Baghdad

about 825 A.D. by the Arab mathematician

Mohamad ibn-Musa al-Khowarizmi


Mathematics as Mechanized Thinking

• Use mathematics to change scientific statements. If the original

statement is correct, and you follow the rules faithfully, your final

statement will also be correct.

This is a new statement about nature - derived using the rules of

mathematics. Using mathematics, physicists can discover new

relationships among physical quantities - mathematics mechanizes

thinking.


Scientific Measurements

Measurements

• relate to how much you know

about something

• of pinhole images of the Sun

nicely lead to a calculation

of the Sun’s diameter


Measurement

• Measurement is one of the first intellectual

achievements of early humans.

• People learned to measure before they

learned how to write and it was through

measurement that people learned to

count.

• Since humans have ten fingers, we

learned to count by tens


Early Measurement Units

• inch - the width of the thumb.

• digit - the width of the middle finger (about 3/4 inch)

• palm - the width of four fingers (about 3 inches)

• span - the distance covered by the spread hand (about 9 inches)

• foot - the length of the foot. Later expressed as the length of 36 -

barleycorns taken from the middle of the ear (about 12 inches).

• cubit - distance from the elbow to the tip of the middle finger (about

18 inches).

• yard - distance from the center of the body to the fingertips of the

outstretched arm (about 36

• inches).

• fathom - distance spanned by the outstretched arms (about 72

inches).


Scientific Methods

Scientific Methods

• There’s no one method in which scientists do

their work.

• Common steps of most methods:

1. observe

2. question

3. predict

4. test predictions

5. draw a conclusion


The Scientific Attitude

The scientific attitude is one of

• inquiry

• experimentation

• willingness to admit error



Scientists

• are experts at changing their minds

• must accept experimental findings

– test for erroneous beliefs

– understand objections and positions of

antagonists

– Subject work to peer reviews


The Scientific Attitude Fact

a close agreement by observers about the same

phenomenon

Hypothesis

• an educated guess presumed to be factual until

supported by experiment

• scientific if there is a test to prove it wrong


Which of these is a scientific hypothesis?

A. The Moon is made of green cheese.

B. Atomic nuclei are the smallest particles in nature.

C. A magnet will pick up a copper penny.

D. Cosmic rays cannot penetrate the thickness of your Conceptual

Physics Fundamentals textbook.


CHECK YOUR NEIGHBOR


Which of these is a scientific hypothesis?

A. The Moon is made of green cheese.

B. Atomic nuclei are the smallest particles in nature.

C. A magnet will pick up a copper penny.

D. Cosmic rays cannot penetrate the thickness of your Conceptual Physics

Fundamentals textbook.

Explanation:

All are scientific hypotheses! All choices not only have tests for proving

wrongness, but have been proved wrong. Nevertheless, they still pass the test of

being a scientific hypothesis.


CHECK YOUR ANSWER


Which of these is not a scientific hypothesis?

A. Protons carry an electric charge.

B. Undetectable particles are some of nature’s secrets.

C. Charged particles will bend when moving in a magnetic field.

D. All of the above are scientific hypotheses.


CHECK YOUR NEIGHBOR


Which of these is not a scientific hypothesis?

A. Protons carry an electric charge.

B. Undetectable particles are some of nature’s secrets.

C. Charged particles will bend when moving in a magnetic field.

D. All of the above are scientific hypotheses.

Explanation:

If protons didn’t carry electric charge, they wouldn’t be deflected when crossing a

magnetic field. This would be a test for showing the hypothesis wrong. So both A

and C are capable of being proved wrong, which makes them scientific. Statement

B, however, has no test for wrongness. It is reasonable speculation—but not a

scientific hypothesis.


CHECK YOUR ANSWER



Law or principle

• a hypothesis that has been tested repeatedly

and has not been contradicted

Theory

• a synthesis of a large body of information that

encompasses well-tested and verified

hypotheses about certain aspects of the natural

world


Which of these often changes over time with further study?

A. Facts

B. Theories

C. Both of the above

D. Neither of the above


CHECK YOUR NEIGHBOR


Which of these often changes over time with further study?

A. Facts

B. Theories

C. Both of the above

D. Neither of the above

Explanation:

Both can change. Is this a weakness or strength of science? For example, if

everything a child holds true is unchanged when that child grows up, with years of

study, even receiving advanced degrees, then either nothing was learned or the

child was unusually gifted from the start—or was part of a closed system. As we

learn new information, we refine our ideas. Likewise with the fields of science.


CHECK YOUR ANSWER


A person who says, “that’s only a theory” likely doesn’t

know that a scientific theory is a

A. guess.

B. number of facts.

C. hypothesis of sorts.

D. vast synthesis of well-tested hypotheses and facts.


CHECK YOUR NEIGHBOR


A person who says, “that’s only a theory” likely doesn’t

know that a scientific theory is a

A. guess.

B. number of facts.

C. hypothesis of sorts.

D. vast synthesis of well-tested hypotheses and facts.

Explanation:

Theory in everyday speech is vastly different than its use in science. A vast and

verifiable body of knowledge isn’t only a theory; if it passes all its tests, it is

elevated to that status! Newton’s theory of gravity and Einstein’s theory of

relativity, for example, are not idle hypotheses—both are supported by

innumerable experiments. They are more than only theories.


CHECK YOUR ANSWER


Science, Art, and Religion

Comparison of science, art, and religion by:

• domain

– science is of natural order and in discovering

and recording natural phenomena

– art is the interpretation and expression of

human experience

– religion involves faith and worship of a

supreme being


Similarities in Art and in Science

– knowledge of what

is possible in

human experience

and in nature

– knowledge of both

affects our views

and decisions of

the world


Similarities in Religion and in

Science

– both deal with

unanswered

questions



Leonardo da Vinci draws a hygrometer


Between a pilot and a priest, who do you think should fly a

commercial jet airplane? Who should perform a marriage?

(Although the questions are no-brainers, they have a point.)

A. The pilot should fly the plane and the priest conduct a marriage.

B. The priest should fly the plane and the pilot conduct a marriage.

C. The pilot should conduct both.

D. The priest should conduct both.


CHECK YOUR NEIGHBOR


Between a pilot and a priest, who do you think should fly a

commercial jet airplane? Who should perform a marriage?

(Although the questions are no-brainers, they have a point.)

A. The pilot should fly the plane and the priest conduct a marriage.

B. The priest should fly the plane and the pilot conduct a marriage.

C. The pilot should conduct both.

D. The priest should conduct both.

Explanation:

The point of the questions is that the pilot and priest have nurtured different skills

for different tasks, and each can do their thing well. Okay, one could argue that a

pilot could adequately do both. But it would be a stretch to say a priest could do

both, unless the priest also had training as a pilot.


CHECK YOUR ANSWER


Science and Technology

• Science is concerned with gathering and

organizing knowledge.

• Technology is the use of scientific

knowledge for practical purposes and to

provide tools for further exploration.


Physics—The Basic Science

• Physical sciences include geology, astronomy,

chemistry, and physics.

• Life sciences include biology, zoology, and

botany.

• Physics underlies all the sciences.


Although physics may be the most difficult science course

in certain schools, when compared with the fields of

chemistry, biology, geology, and astronomy, it is

A. the simplest.

B. still the hardest!

C. the central science, in between chemistry and biology.

D. simple enough, but only for especially intelligent people.


CHECK YOUR NEIGHBOR


Although physics may be the most difficult science course

in certain schools, when compared with the fields of

chemistry, biology, geology, and astronomy, it is

A. the simplest.

B. still the hardest!

C. the central science, in between chemistry and biology.

D. simple enough, but only for especially intelligent people.

Explanation:

Just compare the list of terms in the physics chapters of this book with the lists in

chapters of other textbooks. Which lists are shortest? Chemistry, and especially

biology, are enormously more complex than physics. Physics is much more

understood than the other fields—which is why this book begins with physics—a

foundation for chemistry, biology, geology, and astronomy.


CHECK YOUR ANSWER

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