Hi I'm professor Lou and I'm a
physicist.
The scientific method
starts with a question
A real question that matters to
you.
One you really want to know the
answer to.
For example, how tall is
a particular skyscraper.
If that skyscraper is too tall
for you to get a ruler out
and measure it,
What are you gonna do?
You can go to the janitor
and asked them,
"How tall is your skyscraper?"
but barring that, you're gonna
have to figure out
some method of making the
measurement indirectly.
With your question in mind. How
tall is that skyscraper?
You set about doing some
background research.
You're trying to find
ideas for measuring
the height of the building,
without taking out a ruler.
So, look for example,
how the sunlight travels
across the building. Is there
something you can use there?
No, doesn't look good.  You
try to see whether you can use
a protractor and a calculator.
Finally, it occurs to you that,
Maybe, if I drop something
off the top of the building,
and time how long it takes that
object fall to the ground,
There might be a relationship
between the fall time
and the height of the fall.
That's then a hypothesis.
An idea. You were looking at
the world and your saying,
"Boy, I'll bet there's a
relationship between fall time,
and fall height."
Hypothesis.
An idea based on observations
prior to your experiment,
and it must be testable.
With that hypothesis in mind,
you set about trying to prove it
or disprove it.
Is their relationship
between the fall time
and the fall height or not?
Let's go see.
You find some buildings that are
relatively short,
so that you can measure
their height with a ruler,
and you drop things off
those buildings.
And you time the falls.
Try a short building, measure
the fall.
Try a slightly taller
building, measure the fall.
Taller still, measure the fall.
And then you look for
the relationship between
the time it took for the fall
and how tall the building was
and lo and behold, you discover
their is a relationship.
It turns out that the distance
the object fell is proportional
to the square the fall time.
Wow, that's a very useful
observation.
And with your experience
dropping the object
off short buildings,
you can now go to the tall
building,
drop an object off of it.
Time the fall,
and figure out how tall that
building is.
Experiment.
When conducting an experiment
you can make observations
with your senses and with the
help of instruments.
The variable that
you can control
is the heights the building.
The independent variable.
The thing you can't
control that you're measuring,
you're observing,
is the fall time and technically
that's called
the dependent variable.
To be meaningful and useful,
an experiment has to be
reproducible,
If every time we do the
experiment
you get a different
random result.
it's not much of an experiment
at all.
You certainly can't use the
results.
Collecting data.
Use a bound journal to
record your observations
in an organized clear manner.
A good scientist will be paying
attention to
all the other things
that might or might not
be controllable
as you're doing the measurement.
For example, what's the
temperature today?
What's the humidity? Is the wind
blowing?
Once you collected your data,
they're not science yet.
The science comes from
analyzing those data
and developing models that fit
the data,
and they can be useful
for explaining our world.
Once you analyzed your
measurements and found out
whether you could have proven
or disproven your hypothesis,
it's time to report your
results.
So, what have we learned.
The scientific method includes
the following steps:
Ask a question.
The scientific method starts
with a question.
What you trying to solve
about the world around you?
Conduct background research.
To answer your question
you begin by doing background
research.
You look at ways which you might
possibly answer that question.
Develop a hypothesis.
Once you're background research
has shown you a promising path,
you develope a hypothesis.
An educated guess about
the relationship
between
independent variables,
and dependent variables.
Design an experiment.
To prove or disprove your
hypothesis,
you design experiment,
in which you adjust the
independent variables
and measure the dependent
variables.
Analyze the data to develop a
conclusion.
Once you've major measurements
it's time to analyze them.
You look for relationships then,
between the independent
variables that you could control
and the dependent ones that you
observe.
Communicate the findings.
Once you've analyzed your
measurements
and seen whether they fit or
don't fit the hypothesis,
it's time to report your
results.
Doing science is like solving
puzzles,
it's like detective work.
Where there are answers out
there to be found,
But you have to hunt for them.
So it can be a lot of fun.
There is no single
approach to doing science.
Scientists vary their approach
depending upon the question
that they are trying to answer.
