knowledge, science, and the universe chapter 1 - Physical Science ...

6
C h A p T E R 1
Knowledge, Science, and the Universe
figure 1.4
Sensory data taken under carefully controlled conditions tells us how the universe acts.
hypothesis
A tentative explanation for
an observation, phenomenon,
or scientific problem
that can be tested by further
investigation.
appearance. Perhaps you have had the delight
of being fooled by a magician. He showed you
his empty hands and then a second later produced
a bird in them, seemingly from nowhere!
Most of us have heard about, or even experienced,
a “virtual reality” room where individuals
can be outfitted with sensors that track
their every move. They might wear goggles that
tell their eyes and ears they are moving through
a jungle or climbing a mountain when it really
isn’t so.
A weakness of the senses is that they can be
tricked or fooled, or their sensitivity and accuracy
can diminish with time or injury. How do
we know if what we sense is always accurate
1–2 ThE SCIENTIfIC METhOd
The scientific method uses all four shared
sources of knowledge. Authority is very important.
Library shelves are filled with technical
papers and books reporting research results
from scientists all over the world. Scientific
exploration begins by reading what others have
learned from their experiments and studies.
Intuition may be used in the choice of topics
or basic ideas. Scientists are often guided by
intuition and authority in deciding which studies
to pursue and how to pursue them.
Nonetheless, the scientific method relies mostly
on the other two ways of obtaining knowledge:
reason and sensory data.
You may have been taught the scientific
method through a science fair project in high
school. If so, you probably first made a hypothesis
about something and then designed an
experiment to test it. A hypothesis is usually a
“first guess,” a reasoned conjecture about what
might be happening, based on intuition and
the limited knowledge at hand. For example,
Albert Einstein began his Special Theory of
Relativity by first hypothesizing that the speed
of light in empty space is always constant.
Hypotheses are tested through sensory data
obtained in experiments. After sufficient testing
the hypothesis will be refined, focused, possibly
combined with other hypotheses, and
emerge as a theory. The Special Theory of
Relativity was a theory only after Einstein and
others made quantitative, verifiable predictions
about motion, space, and time from it. Theories
generally possess a greater level of mature detail
than hypotheses do.
Theories that have been proven accurate
and never witnessed to be contradicted are often
called laws, such as Newton’s laws of motion
or the law of gravity. Laws are theories that are
so well tested and proven that further testing is
deemed not necessary. They are assumed to be
true, and are placed in the foundation of scientific
knowledge. No law is hard and fast, however.
Sometimes unexpected discoveries call
long- standing laws into question, leading to
true revolutions in science.
Science uses reason based upon its laws,
theories, and hypotheses to create models of
reality. Models are schematic descriptions of
Theory
A set of statements or principles
devised to explain a
group of facts or phenomena,
especially one that
has been repeatedly
tested or is widely
accepted and can be
used to make predictions
about natural phenomena.
Law
A well-tested theory, so firm
as to be unquestioned by
science.
Model
A schematic description of
a system, theory, or phenomenon
that accounts for
its known or inferred properties
and may be used for
further study of its characteristics.
figure 1.5
Models are used to represent reality. Science leads us to truth
by building models and refining them through theory and
data. This picture of the atom shows electrons orbiting a
nucleus. As we will learn later in the book, this model is useful
for some things but is not very accurate.
+