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Scientific Method
Scientific Method
Scientific Method
What is scientific inquiry?
The ways in which
scientists study the
natural world…
…and propose
explanations based
on the evidence they
gather
Scientific Method
What is scientific inquiry?
If you have ever tried
to figure out why your
iPod or computer is not
working…
…you have used
scientific inquiry
The Scientific Method
Begins with
a problem
or question
about an
observation
Scientific Method
Some questions cannot be
answered by scientific
inquiry
Why has my iPod stopped
working?
What kind of music should I
listen to on my iPod?
Scientific Method
Why has my iPod stopped
working?
This is a scientific question
because it can be answered
by making observations and
gathering evidence
Scientific Method
What kind of music should I
listen to on my iPod?
This question has to do with
personal opinions or values
and is not a scientific
question
Scientific Method
Which of the following questions
can be answered by scientific
inquiry?
Is running a better sport than
swimming?
Does running make your
muscles stronger than
swimming?
Which brand of running shoes
looks best?
Scientific Method
Questions come from experiences
or observations you have
It is a really hot
summer night
You notice that
the crickets are
chirping louder
than usual
Scientific Method
Begin posing
questions…
Why are the
crickets
chirping louder
tonight?
?
Scientific Method
Individual/Group Activity
Posing Questions
Scientific Method
After choosing a topic to
investigate and writing a
testable research question
Collect Information
Scientific Method
Collect Information
Determine Variables
Scientific Method
What are variables?
Variables are all the
factors that can
change in an
experiment, possibly
affecting the results
Scientific Method
Variables
It is important
that you test
only one
variable at a
time
Scientific Method
Variables
This way you
can be sure it’s
the one thing
that caused the
results
Scientific Method
In any Scientific
Investigation there are 3
types of Variables
Independent
Dependent
Controlled
Scientific Method
The Independent
(Manipulated) Variable
The ONE factor or
condition that is
intentionally
changed by the
experimenter
Scientific Method
The Dependent
(Responding) Variable
The factor or
condition that is
affected by the
independent
variable
Scientific Method
The Controlled Variables
All the factors or
conditions that
must be kept the
same in an
experiment
Scientific Method
The M&M Example
Will M&M color
dissolve faster in
water or in
vinegar?
Scientific Method
The M&M Example
What is the
Independent
Variable?
Type of liquid
Scientific Method
The M&M Example
What is the
Dependent
Variable?
Time it takes
for color to
dissolve
Scientific Method
The M&M Example
What are the
controlled
variables?
Color of M&M
Amount of liquid
Type of M&M
Scientific Method
Individual/Group Activity
Variables in Experiments
Scientific Method
Forming a Hypothesis
What is a
Hypothesis?
Scientific Method
Forming a Hypothesis
A hypothesis is a
special type of
prediction that is a
possible explanation
for a set of
observations or an
answer to a scientific
question
Scientific Method
Forming a Hypothesis
When you form a
hypothesis you are
trying to answer your
research question
BEFORE you
experiment
Scientific Method
Forming a Hypothesis
Then you carry
out investigations
and gather
evidence to prove
or disprove your
hypothesis
Scientific Method
Scientific Method
Developing a Hypothesis
Pose question - Do
crickets chirp more
when the
temperature is
higher?
Hypothesis – cricket
chirping increases at
higher air
temperatures
Scientific Inquiry
Developing a Hypothesis
Remember - A
hypothesis is a possible
explanation for a set of
observations or answer
to a scientific question
Scientific Inquiry
Developing a Hypothesis
Important!
A hypothesis is not a
fact. It is one possible
way to explain a group
of observations
Scientific Inquiry
Developing a Hypothesis
Maybe you had more
windows open that
night so the crickets
sounded louder
Maybe there were
more crickets around
that night
Scientific Inquiry
Designing an Experiment to
test your hypothesis
Hypothesis – cricket
chirping increases at
higher air
temperatures
How will you design
your experiment?
Scientific Inquiry
Designing an Experiment to
test your hypothesis
Counting how many times
crickets chirp when the
temperature is high
How will you know how
many times the crickets
would chirp at a lower
temperature?
Scientific Inquiry
Designing an Experiment to
test your hypothesis
You need to observe
crickets at different
temperatures – the
temperature is a
variable
Scientific Inquiry
Designing an Experiment to
test your hypothesis
What is a variable?
Variables are factors
that can change
during an experiment
Scientific Inquiry
Designing an Experiment to
test your hypothesis
Examples of Variables
in your experiment
would be…
Type of crickets
Type of container
?
Scientific Inquiry
Controlling Variables
To test your hypothesis you
purposely change one
variable and make sure all
other variables stay the
same
What variable are you
purposely changing in
this experiment?
Scientific Inquiry
Controlling Variables
The temperature
You need to observe
crickets at different
temperatures
Scientific Inquiry
Controlling Variables
The one variable
that is purposely
changed to test a
hypothesis is
called…
The Manipulated Variable
(also known as the
independent variable)
Scientific Inquiry
Controlling Variables
The factor that may
change in response to
the manipulated
variable is called…
The Responding Variable
(also known as the dependent
variable)
Scientific Inquiry
Controlling Variables
In this experiment the
manipulated variable is…
The air temperature
In this experiment the
responding variable is…
The number of cricket chirps
Scientific Inquiry
Controlling Variables
By keeping all variables
the same (CONTROLLED)
except for temperature…
Identical containers
Identical thermometers
Identical leaves
Identical crickets
(type and number)
Scientific Inquiry
Controlling Variables
…and manipulating
only the variable of
temperature…
o
Container 1 = 15 C
o
Container 2 = 20 C
o
Container 3 = 25 C
Scientific Inquiry
Controlling Variables
…you will know that any
difference in cricket chirping
must be due to temperature
Scientific Inquiry
Controlling Variables
An experiment in which
only one variable is
manipulated at a time is
called…
A Controlled experiment
Scientific Inquiry
Setting up a Controlled Experiment
Suppose we decide
to test the
o
crickets at 15 C in theo morning
and
the crickets at 20 C and
o
25 C in the afternoon…
Is this a controlled experiment?
Scientific Inquiry
Setting up a Controlled Experiment
No! This experiment would
have 2 manipulated variables
– temperature and time of day
Would increased
chirping be due to…
Temperature difference?
Time of day?
Scientific Inquiry
Forming Operational Definitions
A statement that describes
how to measure a particular
variable or define a particular
term is called…
An Operational Definition
Scientific Inquiry
Forming Operational Definitions
For our experiment we need
an operational definition of
how we are going to time and
count the “chirps”
Scientific Inquiry
Collecting and Interpreting Data
Data – the facts, figures, and
other evidence gathered
through observations
Scientific Inquiry
Forming Operational Definitions
A statement that describes
how to measure a particular
variable or define a particular
term is called…
An Operational Definition