PROFESSOR: Well, hello class.
We're going to continue our
discussion of this chapter
of Science is a way of knowing.
In the previous
two chapters we've
talked about mathematics in
units of measurements including
the metric system.
In this video
lesson, we're going
to talk about the
scientific method.
That is, this
formal process that
describes how science is done
in the most ideal [? sense. ?]
Actually, science can occur
in a lot of different ways,
but we like to refer back
to this very formal way
in which science can be
done or should be done.
And that involves the following
steps, an iterative stepwise
process in an
attempt to understand
some natural phenomenon.
It usually starts
with an observation
in which a scientist is trying
to explain or understand
some natural behavior,
natural phenomena.
And in doing this, a
scientist will generally
devise a hypothesis.
A hypothesis is an educated
guess on how something operates
or how the phenomena
behaves or what
the basis is for a phenomena.
The next step is experimentation
or observational test
of the hypothesis, followed
by the evaluation of one's
results, and then these
results will generally
either support the hypothesis
or refute the hypothesis.
Of course, if your hypothesis
is refuted in particular,
you would refine the
hypothesis and perform
additional experimental
or observational tests
of the hypothesis.
That is an iterative
process, repeat the steps
until an understanding
is achieved.
So you observe the
phenomena, come up
with an educated
guess or hypothesis
of what the basis
for the phenomena is,
and experimentally
test that hypothesis.
Evaluate results, revise, et
cetera until understanding
is achieved.
So that's the basic steps
in the scientific method.
In this slide, I show
four important terms
that are used with respect
to the scientific method.
Hypothesis, model, theory,
and law, which in some sense
may seem like they overlap or
they mean maybe the same thing,
but actually they
have distinct meaning.
A hypothesis is a
conjecture, an educated guess
about how something works.
And hypotheses are
what we would try
to test in order to
further understand
the basis for a process.
When the scientists achieve
some level of understanding
of a natural process,
he or she may develop
a model for that process.
A model is often
a visual depiction
of how phenomena works or
some logical framework.
Almost think of that
as a cartoon or drawing
of how something operates.
If a model is supported by
studies by other scientists,
and if it withstands many
challenges and many tests
over a time and can explain a
wide variety of observations,
it might eventually become
what's called a theory.
A theory, an
extensive explanation
of a phenomenon or
related phenomena
that are supported by
a vast body of evidence
and has withstood repeated
challenges or repeated tests.
I like to describe a theory
as a grand explanation.
And the fourth term
on the list is law.
The law is generally a
short pithy statement
or an equation that
summarizes the behavior
of a natural system.
So if you might
think of an equation,
these are some
equations you don't
need to know but, f equals
ma, force is mass times
acceleration.
We'll see that a little later.
PV equals nRT.
You've probably heard
of E equals MC squared.
Those would be scientific
loss or a statement
of Newton's Laws.
Now notice that the terms
hypothesis and theory
have different meanings.
In our ordinary discourse,
people oftentimes
interchange two terms
hypothesis and theory.
And, in fact, there's
usually a tendency
to use the word theory
more often than hypothesis
when, in fact, one really
probably means hypothesis.
I did a little Google
search and there
are like six times as
many hits on the phrase,
it's my theory, much more
than, it's my hypothesis.
As we've said, to a
scientist, a theory
means a grand explanation.
It's something like
the theory of gravity,
whereas a hypothesis is a guess
or a preliminary exploration
or a possible
proposed explanation.
Actually, we'll see a
little so that there
are relatively few theories.
In fact, if you have
room full of scientists,
it's likely than
not a single one has
been the author of a theory.
Yet, if you had a room
full of political pundits
or journalists or politicians,
as soon as the cameras go on,
everyone has a theory.
It's just a different
uses of the term.
And you can see
that that may lead
to some confusion
between a scientist who
has a separate definition
or understanding of the term
theory and hypothesis verses a
non scientists who might have
a different understanding
where the terms hypothesis
and theory might
be interchanged.
Just remember that when
you're talking to a scientist,
if they use word the
theory, they oftentimes
mean it with a capital T,
like the Theory of Gravity,
the grand explanation.
As I said, theories
are few and important.
There are the theories related
to classical mechanics,
the Theory of Relativity and
Quantum Theory, the Big Bang
Theory, Theory of Gravity,
Theory of Electromagnetism.
In the area of
chemistry, there's
Atomic Theory, Kinetic
Theory of Gases,
Molecular Orbitals Theory,
Transition State Theory,
et cetera.
In biology, there's Cell
Theory, the Theory of Evolution,
Germ Theory.
And in Geo sciences, there would
be the Plate Tectonics Theory
and Climate Change Theory.
But this is actually a
relatively short list
of capital T theories.
In this class and the second
semester of this course,
we will actually go over
most of these theories.
In this slide, I want to talk
about some characteristics
of the scientific method.
The performance of
science generally
is a collaborative process.
Scientists rarely
work by themselves.
They oftentimes work in
groups and collaborate
with one another.
One of the hallmarks of
science is reproducibility.
That is, if a scientist is
making some measurements,
he or she will want to be able
to determine whether or not
they can repeat that
measurement so they can then
trust the value.
So reproducibility is important.
In the last several lectures
we talked about precision
in accuracy and in errors.
So scientists are
very much concerned
about their ability to
reproduce their measurements.
Another characteristic
of science
is that there's an open
dialogue in the sharing of data
and the results.
Scientists often go to
scientific meetings,
and they talk to each
other, and they give papers,
and they share the
results because this
is a way of actually
verifying and testing data.
Science also is characterized
by the use of logical reasoning
processes, both inductive
and deductive logic.
And the use of mathematical
tools, as we've said earlier.
And the reliance on measurements
in various quantitative
measurements.
In addition, the
scientific method
is an objective approach
to trying to understand
natural phenomena.
Scientists must be open
minded, but they also
must have a healthy
dose of skepticism.
That is, they want to make sure
that they can trust results.
They're oftentimes skeptical
of not only their own results,
but results produced by others.
And this skepticism can
actually be very healthy
in the way science is done.
Scientists have to also be
unbiased in their studies.
Scientists should not approach
a study already having
an outcome predetermined.
A scientist has to be
willing to be open minded
and be able to
accept any outcome.
Also in conducting science,
ethics is very important.
That is, when a
scientists carries out
experiments and reports
results, he or she
has to be honest and
ethical in that reporting.
In particular, if the
research a scientist is doing
is funded by the federal
government, by taxpayers,
then we all have an interest
in that person being honest
and being ethical in their
research and in the reports.
Also, the scientific method
is characterized by its use
of controls and variables.
Independent and dependent
variables and an attention
to sample size.
This gets in the concepts
of research design, which
we will not go
into a great deal,
but the point is that there are
some characteristics of the way
good science is done.
And also, I wanted to add
it all Occam's Razor, which
is sometimes referred to
as the KISS principle.
You all know the KISS
principle, right?
Keep it simple, stupid.
That is, in interpreting
scientific results,
Occam's Razor says
that you should always
try to come up with the
simplest interpretation that
will explain the results, not
some elaborate unnecessarily
complicated interpretation.
Keep it simple, stupid.
Let me show you a
slide which I think
is kind of interesting because
it depicts some of the ways
the scientists use the
controls and variables.
On the left-- and
this is a slide
that comes from a
textbook that we
may be using-- you see an
array of plots on in a field.
The experiment is being
done is that the scientist
is varying the amount of
fertilizer components.
Phosphates, and
potassium, and nitrogen
in the different
squares in determining
which plants will thrive,
and whether or not plants
in certain of these plots
subjected to certain fertilizer
treatments can survive
better in certain climates
or certain temperatures.
You notice the array and
the way the scientists
is setting up a
sets of variables,
having different fertilizer
in the different plots.
And this type of study
done by someone perhaps
in the field of
agriculture or botany
can be similar in many ways
to an experiment designed
by a chemist, where we
intend to use test tubes.
Where each test tube might
contain a different amount
of some chemical.
Also it brings to my mind,
this is an overhead view
of the biological field station
which is just 15 miles or so
away from the university.
And you'll notice in the
bottom part of this photograph
a set of squares.
These squares are
actually ponds.
And notice how the
ponds form an array very
similar to the
array of test tubs
or the array of
plots in the field
where scientists can
study various variables
placed into these
different ponds.
And if you blow this
up to higher altitude,
you can see not
only that first set
of ponds-- which is now in the
upper part of this diagram--
but you can see there
are other larger ponds
and a whole string of ponds
in this field station.
Wanted to mention
a few other things
about scientific
process, and the first
is the importance
of peer review.
In conducting science, the
way we affirm our results
is by publishing
them in journals.
It's pretty dry reading most
the time, but what is important
is the peer review process.
For a scientist to publish an
article of his or her finding,
that article is reviewed
by other scientists
in the field who
read the article
and make a recommendation
as to whether or not
it's worthy of being published.
So in doing science,
the results are always
reviewed by other
people in the field.
This is a consensus
building process.
So that if certain results
withstand both this peer review
and repeated experiments
by other scientists,
sometimes experiments
attempting to challenge
the results of [INAUDIBLE] that
is the body of the evidence,
the research results themselves,
will lead to a consensus.
And so scientific models
and laws and theories
are constantly being
reviewed and challenged
and tested over
time by scientists,
sometimes leading to revisions.
In this course,
we'll give a number
of examples of how our
understanding of nature,
certain theories that
existed at one time, where
certain theories were
revised and updated
and sometimes replaced
by other theories.
That's the way science is done.
It is a consensus building
and iterative process always
subject to review.
OK, we'll pause
again for a quiz,
and then we'll come and
talk about various branches
of science.
See you in a while.
