Let's explore the scientific method. Which at first might seem a
bit intimidating, but when we walk
through it, you'll see that it's actually
almost a common-sense way of looking
at the world and making progress in our
understanding of the world and feeling good
about that progress of our understanding
of the world.
So, let's just use a tangible example
here, and we'll walk through what we could
consider the steps of the scientific
method, and you'll see different steps
articulated in different ways, but they all
boil down to the same thing.
You observe something about reality, and you say,
well, let me try to come up with
a reason for why that observation
happens, and then you try to test that explanation.
It's very important that you come up with
explanations that you can test, and then you
can see if they're true, and then based on
whether they're true, you keep iterating.
If it's not true, you come up with another explanation.
If it is true, but it doesn't explain everything,
well once again, you try to explain more of it.
So, as a tangible example, let's say that you live in,
in I don't know, northern Canada or something, and let's
say that you live near the beach, but there's
also a pond near your house, and you notice that
the pond, it tends to freeze over sooner in
the Winter than the ocean does.
It does that faster and even does it at higher
temperatures than when the ocean seems
to freeze over.
So, you could view that as your observation.
So, the first step is you're making an observation.
Observation.
In our particular case is that the pond freezes
over at higher temperatures than the ocean
does, and it freezes over sooner in the Winter.
Well, the next question that you might
wanna, or the next step you could view as
a scientific method.
It doesn't have to be this regimented, but this
is a structured way of thinking about it.
Well, ask yourself a question.
Ask a question.
Why does, so in this particular question, or in
this particular scenario, why does the pond tend
to freeze over faster and at higher temperatures
than the ocean does?
Well, you then try to answer that question, and this
is a key part of the scientific method,
is what you do in this third step,
is that you try to create an explanation, but what's
key is that it is a testable explanation.
So, you try to create a testable
explanation.
Testable explanation, and this is kind of the
core, one of the core pillars of the scientific
method, and this testable explanation is called
your hypothesis.
Your hypothesis.
And so, in this particular case, a testable
explanation could be that, well the ocean is
made up of salt water, and this pond is
fresh water, so your testable explanation
could be salt water,
salt water has lower freezing point.
Has lower freezing,
freezing point.
Lower freezing point, so it takes colder
temperatures to freeze it than fresh water.
Than fresh water.
So, this, right over here, this would
be a good hypothesis.
It doesn't matter whether the hypothesis is
actually true or not.
We haven't actually run the experiment, but it's
a good one, because we can construct an
experiment that tests this very well.
Now, what would be an example of a bad
hypothesis or of something that you couldn't
even necessarily consider as part of the
scientific method?
Well, you could say that there is a
fairy that blesses that blesses, let's
say that performs magic,
performs magic
on the pond
to freeze it faster.
Freeze it faster.
And, the reason why this isn't so good is that
this is not so testable, because it's depending
on this fairy, and you don't know how to convince
the fairy to try to do it again.
You haven't seen the fairy.
You haven't observed the fairy.
It's not based on any observation, and so
this one right over here, this would not
be a good hypothesis for the scientific
method, so we would wanna rule that one out.
So, let's go back to our testable explanation,
our hypothesis.
Salt water has a lower freezing point than fresh water.
Well, the next step would be to
make a prediction based on that, and this is the
part where we're really designing an experiment.
So, you could just view all of this as designing.
Let me do this in a different color.
Where we wanna design an experiment.
Design an experiment.
And in that experiments lets say, and let's see,
the next two steps I will put as
part of this experimental.
Whoops.
I messed up.
Let me, I did my undo step.
So, the next part that I will do is the experiment.
Experiment.
And there you go.
So, the first thing is, we'll say I take, you know,
there's all sorts of things that are going on outside.
The ocean has waves.
You know, maybe there are boats going by
that might potentially break up the ice.
So, I just wanna isolate that one variable that
I care about, whether something is salt
water or not, and I want a control for
everything else.
So, I want a control for whether there's
waves or not or whether there's wind or any
other possible explanation for why the
pond freezes over faster.
So, what I do, in a very controlled environment
I take two cups.
That's one cup and two cups, and I put
water in those cups.
I put water in those cups.
Now, let's say I start with distilled water, but then
this one stays, the first one right over here
stays distilled, and distilled means that through
evaporation I've taken out all of the impurities
of that water, and in the second one
I take that distilled water, and I throw a bunch
of salt in it.
So, this one is fresh, very fresh, and in fact,
far fresher than you would find in a pond.
It's distilled water.
And then this is over here, this is salt water.
So, you wouldn't see the salt, but just for our
visuals, you depict it.
Then we would make a prediction, and we
could even view this as step 4,
our prediction.
We predict that the fresh water will freeze at
a higher temperature than the salt water.
So, our prediction, let's say the fresh freezes
at zero degrees Celsius,
but salt doesn't.
Salt water doesn't.
So, what you then do is that you test your prediction.
So, then you test it.
And how would you test it?
Well, you could have a very accurate freezer that
is exactly at zero degrees Celsius, and you put
both of these cups into it, and you wanna make
sure that they're identical and everything where
you control for everything else.
You control for the surface area.
You control for the material of the glass.
You control for how much water there is.
But, then you test it.
Then you see what happened from your test.
Leave it in overnight, and if you see that the
fresh water has frozen over, so it's frozen
over, but the salt water hasn't, well then that
seems to validate your testable explanation.
That salt water has a lower freezing point than
fresh water, and if it didn't freeze, well it's like,
okay, well maybe that, or if there isn't a difference,
maybe either both of them didn't freeze or both
of them did freeze, then you might say, well, okay,
that wasn't a good explanation.
I have to find another explanation for why
the ocean seems to freeze at a lower temperature.
Or, you might say, well that's part of the
explanation, but that by itself doesn't
explain it, or you might now wanna ask even
further questions about, well, when does
salt water freeze, and what else is it dependent on?
Do the waves have an impact?
Does the wind have an impact?
So, then you can go into the process
of iterating and refining.
So, you then refine,
refine,
refine and iterate on the process.
When I'm talking about iterate, you're
doing it over again, but then, based on
the things that you've learned.
So, you might come up with a more refined
testable explanation, or you might come up
with more experiments that could get you
a better understanding of the difference
between fresh and salt water, or you might
try to come up with experiments for why
exactly, what is it about the salt that makes
this water harder to freeze?
So, that's essentially the essence of
the scientific method, and I wanna emphasize
this isn't some, you know, bizarre thing.
This is logical reasoning.
Make a testable explanation for something
that you're observing in the world, and then
you test it, and you see if your explanation
seems to hold up based on the data from your
test. And then whether or not it holds up,
you then keep going, and you keep refining. And you
keep learning more about the world, and the
reason why this is better than just saying, oh well,
look, okay, I see the pond has frozen over and the
ocean hasn't, it must be the salt water, and you know,
I just feel good about that, is that you can't
feel good about that.
There's a million different reasons, and you
shouldn't just go on your gut, 'cause at some
point, your gut might be right 90% of
the time, but that 10% that it's wrong, you're
going to be passing on knowledge or assumptions
about the world that aren't true, and then other
people are going to build on that, and then all
of our knowledge is going to be built on kind of
a shaky foundation, and so the scientific method
ensures that our foundation is strong.
And I'll leave you with the gentleman who's often
considered to be the father, or one of the
fathers of the scientific method.
He lived in Cairo, and in what is now Egypt,
nearly 1,000 or roughly 1,000 years ago. And he
was a famous astronomer and phycisist and mathematician.
And his quote is a pretty powerful one, 'cause
I think it even stands today:
"The duty of the man who investigates the writings
of scientists, if learning the truth is his goal, ..."
Let me start over, just so I can get the dramatic
effect right.
"The duty of the man who investigates the writings
of scientists, if learning the truth is his goal,
is to make himself an enemy of all that
he reads, and ... attack it from every side.
He should also suspect himself as he performs
his critical examination of it, so that he may
avoid falling into either prejudice or leniency."
Hasan Ibn al-Haytham, and his Latinized name
is Alhazen.
So, he's saying be skeptical, and not just skeptical
of what other people write and read, but even
of yourself. And another aspect of the scientific
method which is super important is, if someone
says they made a hypothesis and they tested and they
got a result, in order for that to be a good test and in
order for that to be a good hypothesis, that experiment
has to be reproducible.
Someone can't say, oh it's only, you know, a certain
time that only happens once every 100 years and not,
that that's why it happened that day.
It has to be reproducible, and reproducible
is key, because then another skeptical scientist
like yourself can say, let me see if I can
reproduce it.
Let me not just believe it, because that person
looks like they're smart, and they said that
it is true.