Hello class this lesson is going to about
the Scientific Method.
The sm is a way to go about solving problems
in their every day life.
A lot of people think that are non-science
majors that " I will never use science", but
that is simply not true.
By you simple picking a product that you like
by trial and error is part of the scientific
method.
So today what I am going to do is go through
the steps of the sm and show you how I have
incorporated the scientific method into my
everyday life.
The SM is a series of steps that people can
take in order to solve their problems.
In order to see if they have a problem to
solve, the first step in the scientific methods
is to make observations.They look at the world
around them and observe it.
From these observations they formulate questions.
From these questions/problems they formulate
a hypothesis.
An educated guess.
From that point they go on to test these hypotheses.
Test by experimentation.
Once they collect the data from these tests,
they then draw conclusions from their data.
These conclusions can fit with they scientific
evidence or they can go against the scientific
evidence.
Once these experiments have been concluded,
they can share this information with the scientific
community through papers and journals.
So it is an ongoing process that is tweaked.
One thing to keep in mind, we can talk about
scientific fact but a scientific fact is different
from a grammatical fact in English or a fact
in history.
Scientific facts can be changes as the scientific
community gains knowledge about the world
around them.
So keep that in mind as we talk about science.
What is true today in science may not be true
in twenty years from now.
For example, when I was a kid, Pluto was considered
a planet.
About 10 or more years ago, with more scientific
data, they no longer called pluto a planet.
Poor Pluto.
So like I said, the first step is observations.
So an example from my life, I LOVE Coffee!!!
I drink it in the morning, have two cups during
the day at work, and then more when I get
home.
I love coffee.
Yes I am addicted to caffeine but it is also
my comfort drink.
I also have an obsession with my teeth.
I have recurring nightmares that my teeth
rote and fall out.
So I take excellent care of my teeth, I brush
them three times a day, I floss, and I whiten
my teeth.
But I observe that coffee causes stains on
my teeth.
Then I can come up with my problem or questions.
I am not going to stop drinking coffee.
So my problem or questions is.. how can I
drink coffee without staining my teeth?
Step three of the sm would be to formulate
a hypothesis.
How can I solve this problem?
There are many solutions to this problem.
But for me and for scientists, you pick one
and you stick with it.
A good hypothesis is an educated guess, answer
to a question stated as a declarative statement.
It is objective, it pertains to everyone,
there is no personalization with including
Is or Mes.
It is a blanket statement that covers everyone.
There is always going to be one independent
variable.
The IV is something you are changing to get
your desired outcome.
The dependent variable is what you are going
to measure as a result of that change.
So my hypothesis to my problem is drinking
coffee through a straw reduces stains on teeth.
See how I did not put I in there or we or
me.
The thing that I am changing or my IV is how
I am drinking coffee.
So drinking coffee through the straw is my
IV.
What I am measuring as a result of that change
are the stains on my teeth.
So stains on my teeth is the DV.
You always have one IV and one DV.
You do not want to have multiple variables.
So I don't want to say drinking coffee 
through a straw and using teeth whitener will
reduce stains on teeth because I will not
know which is causing the change.
So you clearly know what is effecting the
stains.
The next part of the SM is to experiment.
YOu will need to design an experiment that
will actually test your IV.
You need to see if your IV is actually influencing
your DV.
Experiments must be done over a long period
of time.
I can't just drink coffee through a straw
one day and say WHOA I am an awesome scientist!
My teeth have less stains.
I have to do it for a long long duration of
time.
Months.
I have to have many subjects.
Not just me but several people (hundreds if
possible) doing this at the same time.
You always have to have a control group.
A control group is a group that you will compare
your experimental group to in order to see
if your experiment worked.
Your control group has to lack the IV.
So like I said my IV is drinking coffee through
a straw so that is my experimental group.
A group of people that are going to constantly
drink coffee through a straw.
My control group is going to be the same number
of people drinking coffee at the same time,
the same type of coffee, but without the straw.
The reason why you have this group drinking
without the straw is so you can compare the
two groups together.
The one using the straw and the one without
the straw.
So then we can compare the results at the
end so see if there was a real change with
the IV in place.
The experimental group has 
the IV.
Once the 
experiment is over you can draw conclusions.
You will have supported data where you share
with the scientific community and say I am
so smart my experimental data matched my hypothesis
and these are the findings that I have.
You also have to share your data if it doesn't
match.
In good science whether your results go with
your hypothesis or not it is really important
to share so other people can learn from your
experiments.
If it is not supported you can redo the experiment
and try again.
You can tweak your experiment, you can tweak
your variables, you tweak your hypothesis
and redo the experiment.
After that you can reject your hypothesis
and say actually drinking coffee from a straw
does not reduce the stains on teeth.
Or I could create a new hypothesis.
So these are the aspects in the scientific
method.
After you have your hypothesis and it has
been tested and the whole scientific community
agrees with this hypothesis then a hypothesis
can become a theory.
Often, people mistake hypothesis and theory
and use theory all the time but theory means
something very specific.
So a hypothesis is a possible explanation
for a specific observation.
An answer to a problem or question.
It is basically an educated guess.
It is what you think the answer is to a problem.
A theory on the other hand is widely accepted,
typically by the scientific community at large.
They agree to this idea as scientific fact.
It is a broad concept, it covers many ideas
and it shapes how scientists view the world,
and how they form their hypotheses.
It explains why things happen.
so if you think of it, a hypothesis is the
beginning of an idea and the theory is when
that idea is more concrete.
So in order for hypothesis to become a theory
it must be broad and pertain to a whole body
of evidence or ideas.
Must be extensively tested.
One person cannot do a test and say I am smart
I was correct, and now that is a theory.
Many resources and outlets have to test that
same idea and come to the same conclusions.
It must be supported of over time and have
a high degree of reliability.
Keep in mind that scientific fact changes
as more evidence is gathered.
Theories maybe refuted in the future with
evidence that contradicts that theory.
We have the germ theory.
States infectious diseases are caused by microorganisms
that can be transmitted from one person to
another.
This originally was a hypothesis.
People believed that life came from non-living
entities.
Bacteria just showed up.
But that is not true.
We know that the bacteria have to be there
to begin with and bacteria can be transmitted
from person to person.
When these microorganisms multiply in their
host, they cause a disease.
So this is a theory.
This has been experimented this has been observed,
and now it is accepted by the scientific community
that germs are spread via direct contact from
person to person and then those will grow
in the host.
There is also a difference between 
scientific law and a theory.
Scientific law is uniform or a constant fact
of nature.
For example, the law of gravity.
You have all experienced gravity.
You have all fallen.
The Earth is pulling you down at 9.8 /s2.
That is true about everything on this planet.
They get drawn to the earth due to gravitational
forces.
So that is a law.
It describes what happens in the natural world.
So an example is the biological science is
the biogenic law.
This is the law that all living things come
from pre-existing living things.
Picture of buggies.
So in order for these bugs to be adults they
came from preexisting cells from their parents.
Same as you and me.
We came here from a sperm and egg uniting
to make a one-celled organism called a zygote
and that one cell divided to become two and
two divided to become four and continued to
divide until they made you.
Now if you have children, your sex cells your
egg or sperm, will be used to construct a
new individuals.
So cells come from preexisting cells.
Life comes from preexisting life.
That is the biogenic law.
That is accepted by the scientific community.
That ends our lecture today on the scientific
method, the difference between hypothesis,
theory, and law.
