Independent Variable:
Your experiment has one
variable that you will change
to see if the results support
or refute your hypothesis.
What is the one variable you
will change during the
experiment?
Dependent Variable:
The dependent variable is the
change that occurs as a result
of doing the experiment.
This variable is the measure of
the change. How will you
measure the change?
Remember your measurements
must be in numbers that can
be put into a graph. 2013 Science Fair packet K-4th.doc - 9 -
Sample Size:
What will your sample consist
of?
Example: 3 plants X 3 each = 9
total plants
Repeated Investigation:
How many times will you
repeat the experiment for
accuracy?
experiment needs to be
done at least 3 times.
Controlled Variable(s):
Which variables will you
control or keep the same
during your experiment?
. Independent Variable: The independent variable is the amount of air you put in the
balloon. This is the independent variable because in my experiment, I change the
amount of air that I put in each balloon.
2. Dependent Variable: The dependent variable is the distance traveled by the
hovercraft. This is the dependent variable because the distance traveled is
affected by the air in the hovercraft’s balloon.
3. Control Variables: The control variables in this experiment are the travel surface,
hovercraft, and the fans providing thrust. These need to be controlled, or the
experiment will not be even.
There are three types of variables that must be considered when determining
the procedure to be followed:
" Independent variable – the factor that you will change on purpose during
the experiment to find out what effect it has on something else.
Example: different types of materials (silk, felt, canvas, paper, tissues, etc.) to
construct a parachute to observe the effect the type of material has on the
drop time of the parachute
" Dependent variable – the factor that is observed and measured to see if it
is affected by the change made in the independent variable.
Example: The dependent variable in the parachute investigation would be the
time the parachute took to drop.
" Control /Constant variables – the factors in the experiment that must be
kept exactly the same to make sure that they are not having any effect
on the dependent variable. They ensure that you are conducting a fair
test.
Example: Variables that would need to be controlled in the parachute
experiment would be the size of each parachute made, the same mass tied to
the parachute, and the height the parachute were dropped from.
There are three types of variables to consider when designing the investigation
procedure.
• The independent variable is the one variable the investigator chooses to
change.
• Controlled variables are variables that are kept the same each time.
• The dependent variable is the variable that changes as a result of /or in
response to the independent variable.
Having students talk through the investigation will help them to clarify the
different variables involved in the experimental design. What factors will change?
What factors will stay the same?
A hands-on way to introduce a fair test is to ask students, “Who can make the
best paper airplane?” Once two students are selected to compete, hand one a
large piece of construction paper and the other a piece of regular copy paper.
Students will immediately note that this is “unfair.” If we want the test to be fair,
only the paper airplane design can be different. Everything else, including how
hard the airplane is tossed, must be the same. Design Experiment
Once students formulate a hypothesis for their investigation, they must design a
procedure to test it. A well-designed investigation contains procedures that take
into account all of the factors that could impact the results of the investigation.
These factors are called variables.
There are three types of variables to consider when designing the investigation
procedure.
• The independent variable is the one variable the investigator chooses to
change.
• Controlled variables are variables that are kept the same each time.
• The dependent variable is the variable that changes as a result of /or in
response to the independent variable.
Having students talk through the investigation will help them to clarify the
different variables involved in the experimental design. What factors will change?
What factors will stay the same?
A hands-on way to introduce a fair test is to ask students, “Who can make the
best paper airplane?” Once two students are selected to compete, hand one a
large piece of construction paper and the other a piece of regular copy paper.
Students will immediately note that this is “unfair.” If we want the test to be fair,
only the paper airplane design can be different. Everything else, including how
hard the airplane is tossed, must be the same.
Step A – Clarify the variables involved in the investigation by developing a table
such as the one below.
Testable
Question
What is changed? (independent variable)
What stays the same? (controlled variables)
Data Collected (dependent variable) What can be measured?