Variables Lesson Overview
Students Learn
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A pendulum is a mass
supported at a point,
free to swing.
A variable is anything
that you can change in
an experiment that
might affect the
outcome.
In a controlled
experiment only one
variable is changed,
and the results are
compared to a
standard.
As the length of a
pendulum increases,
the number of swings
in a unit of time
decreases.
Two coordinate graphs
can display the
outcome of a controlled
experiment.
Graphs can expose
relationships, which in
turn can be used to
make predicitions
Capacity is the
maximum volume of
fluid a container can
hold.
Variables are things
you can change that
might affect the
outcome of an
experiment.
In a controlled
experiment, only one
variable is changed,
and the results are
compared to a
standard.
The larger the capacity
of a boat, the greater
the number of
passengers it can hold.
Two-coordinate graphs
can display results of
experiments and show
relationships between
variables.
Graphs can be used to
Lesson
Investigation 1
Dropping In
Part 1: Exploring
Swingers
Students Do
Students build and observe standard
pendulums made from string and
pennies. They identify possible
variables that could affect the number
of swings the pendulum makes in 15
seconds.
Part 2: Testing Variable Using controlled experimentation, the
variables of mass, release position,
and length are tested to see how they
affect the number of swings the
pendulum completes in a given amount
of time. Students display their results
on a concrete graph and on a pictorial
graph. They use the graphs to look for
questionable data and to identify the
relationship between the experimental
variable and the outcomes.
Part 3: Predicting
Students are introduced to a twoSwings
coordinate graph. They plot the
swinger data on the new graph and
compare it to the concrete and
pictorial graphs of the same
information. Students use the graph to
make predictions and create
pendulums with new lengths to test
their predictions.
Investigation 2:
Students construct standard paper-cup
Lifeboats
boats and test them “at sea” to find
Part 1: Lifeboats
out how many passengers-penniesthey can carry without sinking. After
identifying variables that influence the
number of passengers they can carry,
students construct three more boats of
differing sizes and determine the
capacity of each boat by measuring
the volume of water each can hold.
Part 2: Lifeboat
Students conduct controlled
Inspection
experiments to discover how many
passengers each boat can hold before
sinking. They graph the data and
discover the relationship between the
capacity of the boat and the number
of passengers it can hold – the larger
the boat, the more passengers it can
support.
Part 3: Inspecting other
Students swap fleets of boats with
make predictions.
Apply the content and
processes developed in
Parts 1 and 2.
Boats
another group. They use the graph of
their experiment to predict the number
of passengers each new boat could
hold, then test their predictions.
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A system is a set of
objects that is working
together.
Investigation 3: Plane
Sense
Part 1: Exploring Flight
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A variable is anything
that you can change in
an experiment that
might affect the
outcome.
The basic unmodified
systems being
investigated in an
experiment is called the
standard.
In a controlled
experiment the
experimental variable
is changed
incrementally to see
how it affects the
outcome.
A two-coordinate graph
displays the
relationship between
an experimental
variable and an
outcome.
Part 2: Investigating
Variables
Students construct a model propellerdriven plane that flies along a fishing
line. They explore how their planes
work and the number of winds needed
to fly the length of the line.
After students have investigated how
many winds of the propeller it takes to
fly their plane half the length of the
line, they identify the variables that
can affect flight. They modify their
planes and control the variables in
further experiments.
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Part 3: Flights of Fancy
Students design controlled experiments
for testing the effect of other variables
on their plane system.
Part 4: Graphing the
Results
Students plot the results of controlled
experiments on two-coordinate graphs.
They present the graphs and describe
the relationship between the
experimental variable and the
distance the plane flies.