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This method of splitting things into smaller and smaller parts and studying
how those parts influence each other is called reductionism. The hope is
that the seemingly complex rules governing the larger units can be better
understood in terms of simpler rules governing the smaller units. To
appreciate what reductionism has done for science, it is only necessary to
examine a 19th-century chemistry textbook. At that time, the existence of
atoms was still doubted by some, electrons were not even suspected to exist,
and almost nothing was understood of what basic rules governed the way
atoms interacted with each other in chemical reactions. Students had to
memorize long lists of chemicals and their reactions, and there was no way
to understand any of it systematically. Today, the student only needs to
remember a small set of rules about how atoms interact, for instance that
atoms of one element cannot be converted into another via chemical
reactions, or that atoms from the right side of the periodic table tend to
form strong bonds with atoms from the left side.
Discussion Questions
A.I’ve suggested replacing the ordinary dictionary definition of light with a
more technical, more precise one that involves weightlessness. It’s still
possible, though, that the stuff a lightbulb makes, ordinarily called “light,” does
have some small amount of weight. Suggest an experiment to attempt to
measure whether it does.
B.Heat is weightless (i.e. an object becomes no heavier when heated), and
can travel across an empty room from the fireplace to your skin, where it
influences you by heating you. Should heat therefore be considered a form of
light by our definition. Why or why not.
C.Similarly, should sound be considered a form of light.
0.3How to Learn Physics
For as knowledges are now delivered, there is a kind of contract of error
between the deliverer and the receiver; for he that delivereth knowledge
desireth to deliver it in such a form as may be best believed, and not as may
be best examined; and he that receiveth knowledge desireth rather present
satisfaction than expectant inquiry.
Sir Francis Bacon
Many students approach a science course with the idea that they can
succeed by memorizing the formulas, so that when a problem is assigned on
the homework or an exam, they will be able to plug numbers in to the
formula and get a numerical result on their calculator. Wrong! That’s not
what learning science is about! There is a big difference between memoriz-
ing formulas and understanding concepts. To start with, different formulas
may apply in different situations. One equation might represent a defini-
tion, which is always true. Another might be a very specific equation for the
speed of an object sliding down an inclined plane, which would not be true
if the object was a rock drifting down to the bottom of the ocean. If you
don’t work to understand physics on a conceptual level, you won’t know
which formulas can be used when.
Chapter 0Introduction and Review