Graphing
Miss Sauer’s 7th Grade Science Class
GRAPHING

AIM: How do you create a graph?
How do you know whether to use a line
graph, a bar graph, or a pie chart?

HOMEWORK: Complete bar graph “Give It a
Try”
DO NOW:

1. Both of these
figures display the
same information but
in different ways.
Which figure is easier
to understand?
Explain.

2. If you need to get
specific data, such as
an exact number of
students who earned a
B, which figure would
you use? Explain.
GRAPHING
Motivation:
http://www.youtube.com/watch?v=zl4NRvE_
V_4

CHOOSING THE RIGHT GRAPH:
Data tables provide an organized way of
viewing information, and graphs are
pictures of the information in a data table.
Sometimes it is faster and easier to
interpret data by looking at a graph. It is
important to choose the type of graph that
best illustrates your data.
 Next we will look at the best uses for 3 of
the most common graphs.

TYPES OF GRAPHS – BAR GRAPH
A bar graph is best
used for
comparing data
quickly and easily,
such as the grade
distribution of
students enrolled
in a science class
or the growth of
plants in different
pots.
Bar Graph - Comparison
TYPES OF GRAPHS – PIE GRAPH
A pie graph is best
used for showing
percentages,
such as the
percentage of the
student body who
picked certain
entrees for lunch
or the percentage
of your allowance
that will go toward
purchasing
various things.
Pie Graph - % (% out of 100%)
TYPES OF GRAPHS – LINE GRAPH
A line graph is best
used for looking
at continuous
data, such as the
number of
bathing suits sold
each month
during the year or
the change in
your sister’s
height throughout
the year.
Line Graph – Continuous Data
MOTIVATION:
TWINART Connect the Dots / Jungle Gym (1:01)
 https://www.youtube.com/watch?v=qt9EFc_7
Wq8

TYPES OF GRAPHS - EXERCISE

What graph type do you think best presents
this set of data? Explain.
TYPES OF GRAPHS - EXERCISE

What graph type do you think best presents
this set of data? Explain.
TYPES OF GRAPHS - EXERCISE

What graph type do you think best presents
this set of data? Explain.
WHAT DO I NEED TO SET UP A GRAPH?
Title
Label x-axis & y-axis
Label x-axis & y-axis units (write in parathentheses
next to the label of the axis)
Scale x-axis & y-axis
Use proper graph (line, pie, bar)
Neatness
Use 75% of the paper
Connect the dots (for a line graph)
Evenly spaced (for a bar graph)
TITLES
Titles include both the independent and dependent
variables.
Example: “The effect of the (IV) on the (DV)”
Or “The relationship between the (IV) & (DV)”
Think of the title as a picture…
INDEPENDENT & DEPENDENT
VARIABLES
**It’s key to know what the IV & DV when you are
graphing!!!
INDEPENDENT & DEPENDENT
VARIABLES
Do you remember what an independent variable is?
Independent Variable is the variable that you
purposely change and test.
Also called the manipulated variable.
Do you remember what a dependent variable is?
Dependent Variable is the factor that may change
as a result of the manipulated variable (depends
on the experiment).
Also called the responding variable.
LABELING THE GRAPH
Pneumatic Device - DRY MIX
Dependent
Responding
Y-Axis
Manipulated
Independent
X-Axis
LABELING THE GRAPH
Time will ALWAYS be the Independent Variable and
go on the x-axis. It is what is being changed.
LABELING THE GRAPH
Look at the graph:
-There is a title, label
on each axis, no units
for this graph, but
would have if there
were units.
-Bar graphs MUST be
neat (use a ruler).
-The bars are not
touching (because
they data is not
related).
The graph should fill ~75% of the page. Scale Properly.
-The bars are equally
spaced.
EXERCISE

For this table (a) identify the independent and dependent
variable, (b) determine the type of graph to use, and (c)
provide a title.
EXERCISE

For this table (a) identify the independent and dependent
variable, (b) determine the type of graph to use, and (c)
provide a title.
SCALING A GRAPH

Scaling the graph means numbering the grid so
that the data can be displayed for comparison.
It is called scaling because you are actually
making a scale, a set value per box / line for
both the x-axis and y-axis.
SCALING A GRAPH

Point of Origin: The first line of the graph. This
is the beginning point of the graph
SCALING A GRAPH
To scale a graph, you first should look at your
data and determine the range of your data. You
will need to include ALL your data on the graph.
 You can then count the number of lines
available on your graph.
 Next, you divide the highest number of your
data by the number of lines available. This will
give you the value of each line on the axis. You
may need to slightly adjust the value of each
line to avoid decimal points.

UNDERSTANDING SCALING
Line Graph Example:
On y-axis we have 40 lines going up.
Our data ranges from 11.0 – 17.3.
We are going to make our math / our lives easier
& use a number that fits our data & divides
easily.
17.3 doesn’t divide easily, but 20 does!!!
20 /
40
= 0.5
(data) / (# of lines) = value of each of the 40 lines

•
We use the same method to scale our x-axis.
UNDERSTANDING SCALING

•
•
•
Bar Graph Example:
We use the same method (we used for a line graph) to
scale our y-axis.
For the x-axis, we need to consider how many “things”
we are comparing.
We DO NOT NEED to divide the number of lines we
have by the number of “things,” but we should
remember to fill 75% of the graph.
Remember: the bars should be EVENLY SPACED &
should NOT touch!
EXAMPLE 1






Select the appropriate graph type.
Identify the independent and dependent variable.
Choose an appropriate scale.
Label the axes.
40.0
Give your graph a title.
Graph the data.
EXAMPLE 2






Select the appropriate graph type.
Identify the independent and dependent variable.
Choose an appropriate scale.
Label the axes.
Give your graph a title.
Graph the data.
80
“GIVE IT A TRY” – (FINISH FOR HW)






Select the appropriate graph type.
Identify the independent and dependent variable.
Choose an appropriate scale.
Label the axes.
Give your graph a title.
Graph the data.
“GIVE IT A TRY” – FOR A
BAR GRAPH
On the y-axis, we use the line graph rules
we have 40 lines going up.
Our data ranges from 11.0 – 17.3.
We are going to make our math / our lives easier & use a number that fits our data
& divides easily.
17.3 doesn’t divide easily, but 20 does!!!
20
/
40
= 0.5

(data-highest point)

/ (# of lines on y-axis)
= value of each
of the 40 lines
On the x-axis, we need to consider how many “things” we are comparing.
We DO NOT NEED to divide the number of lines we have by the
number of “things,” but we should remember to fill 75% of the
graph.
Remember: the bars should be EVENLY SPACED & should NOT touch!
•
CONCLUSION






What is an independent variable?
What is a dependent variable?
What do I need for a graph?
Which graph do I use for comparison?
Which graph do I use for percentages that add up
to 100%?
Which graph do I use for continuous data?
RELATIONSHIPS OF GRAPHS
Direct: the x-axis & y-axis are both doing the
same thing.
 Indirect: the x-axis & y-axis are NOT doing the
same thing.
 Constant: Either the x-axis remains the same &
the y-axis changes OR the y-axis stays the same
& the x-axis changes.
 Cyclic: Displays a pattern & is predictable.

RELATIONSHIPS OF GRAPHS

Direct: the x-axis & y-axis are both doing the
same thing.
Y-axis
X-axis
10
1
1
10
RELATIONSHIPS OF GRAPHS

Indirect: the x-axis & y-axis are NOT doing the
same thing.
X-axis
Y-axis
10
1
1
10
RELATIONSHIPS OF GRAPHS
Constant: Either the x-axis remains the same &
the y-axis changes
 OR the y-axis stays the same & the x-axis
changes.

OR
RELATIONSHIPS OF GRAPHS

Cyclic: Displays a pattern & is predictable.