Focus: Scientific Inquiry Skill: Graphs
Objective: Scientists gather and
organize data
Warm Up: Answer
1. Write the steps for creating a data
table.
2. What is a graph? How is it different
from a data table?
Draw the Axes
Identify the Axes
Y- Axis
X- Axis
Identify the Axes
Y- Axis
Dependent
Variable
(what is
observed and
measured)
X- Axis
Independent
Variable
(what is changed
by the scientist)
DRY MIX
One way to remember which data goes on which axis is
the acronym DRY MIX.
D.R.Y.
D- Dependent
R- Responding
Y- Y-axis
M.I.X.
M- Manipulated
I- Independent
X- X-axis
Title
• Write an appropriate title for the graph at the top.
• The title should contain both the independent and
dependent variables.
Scale
• Decide on an appropriate scale for each axis.
• The scale refers to the min and max numbers used on
each axis. They may or may not begin at zero.
• The min and max numbers used for the scale should be
a little lower than the lowest value and a little higher than
the highest value.
• This allows you to have a smaller range which
emphasizes the comparisons/trends in the data.
Scale
•The Y-axis
scale is from
0-100.
•The largest
value though is
only 35.
Scale
•The Y-axis
scale is now
from 0-40.
•This does a
better job
emphasizing
the
comparisons
between coins.
Intervals
• Look at your minimum and maximum values you set up
for both the Y and X-axis. (For most bar graphs, the Xaxis will not have numerical values.)
• Decide on an appropriate interval for the scale you have
chosen. The interval is the amount between one value
and the next.
• It is highly recommended to use a common number for
an interval such as 2, 5, 10, 25, 100, etc.
Intervals
The interval for
the Y-axis is 20.
The X-axis does
not have
numerical data
and does not
need an
interval.
Labels
• Both axes need to be labeled so the reader knows
exactly what the independent and dependent variables
are.
• The dependent variable must be specific and include the
units used to measure the data (such as “number of
drops”).
Labels
DV label
IV labe
TAILS
Another handy acronym to help you remember
everything you need to create your graphs…..
T.A.I.L.S.
Title
Axis
Interval
Labels
Scale
TAILS
Title: Includes both variables
Axis: IV on X-axis and DV on
Y-axis
Interval: The interval (4) is
appropriate for this scale.
Label: Both axes are labeled.
Scale: Min and max values are
appropriate.
Graphing Rules Notes
Purpose of a Graph: to show data visually
Bar graphs: used for data that is
not connected, such as types of
vegetables
Title
Dependent Variables
100
90
80
70
Y axis label
60
Bars
50
40
30
20
10
0
Independent Variables
X axis label
Title Vegetable Choices of Guinea Pigs
Dependent Variables
100
90
80
70
Y axis label
60
Percentage of
Food Choice
50
Discontinuous Data:
Bar Graph
40
30
20
10
0
Independent Variables
Carrots
Broccoli
X axis label Food Choices
Lettuce
How to Make a Bar Graph
1. Dependent Variable: y-axis
2. Independent Variable: x-axis
3. Number the y-axis
4. Label the x and y-axis
5. Draw a bar for each data value
6. Label each bar
7. Give your graph a title
Graphing Rules Notes
Purpose of a Graph: to show data visually
Line graphs: used for data that is
connected, such as over a period of
time. Lines consist of connected
dots.
Line Graph
• A line graph is a graph used
to show change over time!!
What can time be measured in???
Seconds - Minutes - Hours – Days Weeks - Months – Years - Decades Centuries - etc.
When to use a line graph?
Would we use a line
graph in the following
situations:
•To show how many people like pizza in
this class? NO
•To show how much it rained each month
this year? YES- because months and years deal with time.
•To show how many people live in East
Meadow?
NO
How do we make a line
graph?
Y
X
• A line graph ALWAYS has a
title!
• A line graph has two
different axis’s
• An axis is either the
horizontal line (called x) or
the vertical line (called y)
that form the base lines of a
graph.
Title
Dependent Variables
100
90
80
70
Y axis label
60
Points
50
40
30
20
10
0
Independent Variables
X axis label
Plotting a Line graph
• When we are plotting a line graph, it is
important to read what information is on
each axis.
• There must be a label on each axis that
describes the information.
• Much like a bar graph, we look at the xaxis first in order to plot our points.
Time in minutes
Year
Number
of Cases
of Lead
Exposure
1987
1044
1988
789
1989
884
1990
653
1991
690
1992
807
1993
1900
1994
1988
1995
1718
1996
1382
1997
1156
Is this an acceptable graph?
Car Trip
Time
Bar Graphs vs
Line Graphs
Bar Graphs
•Bar graphs are descriptive.
•They compare groups of data such as amounts
and categories.
•They help us make generalizations and see
differences in the data.
Example
Another example
Line Graphs
•Line graphs show a relationship between the two
variables. They show how/if the IV affects the DV.
•Many times, the IV plotted on the X-axis is time.
•They are useful for showing trends in data and
for making predictions.
Example
Another example