HOW TO WRITE A GRAPH USING EXCEL
A graph is a picture that depicts data that have been listed in a table (refer to “What is a
Table”). Because it is a picture, the graph allows us to interpret the data more easily than
we might do if we were to try to read the table, especially if the table contains pages of
data.
In Science, we follow precise rules when we write a graph. Luckily, you no longer have
to write a graph with paper and pencil, a long and tedious process; instead, you get to use
an Excel spreadsheet and let the laptop do your work for you. Instead of spending five
days learning how to write a graph by hand, you will only need about one class period!
Directions:
1. To make the graph:
a. Highlight all parts of the table EXCEPT the title. Do not highlight any
empty columns.
Chart Wizard
b. SELECTING A LINE GRAPH:
Select the following in the order presented.
CHART WIZARD (it looks like a stack of books)
STANDARD TYPES - LINE (Select the line graph with data
points displayed at each data value. It is the graph on the
left of the middle row. In this VII Science, we only make
line graphs). NEXT (As an alternative, you can double
click on the image)
c. DELETING THE UNWANTED LINE:
Open the SERIES tab.
You need to remove all data lines except the ones you need. For
now, you can ask your teacher if you need to remove a variable
and which one to remove. Later, you will learn which curve
needs to be deleted. In this case, remove Time. In the dialogue
box, highlight the line you wish to remove from the Series table
and then click REMOVE.
d. CORRECTING THE X-AXIS
At the bottom of the SERIES dialogue box, you will find
Category (X) axis labels. Click the icon to the right of the entry
box by this label.
In the table, highlight cells A3 through A9. Do not highlight the
heading.
Next, click the icon to the right of the Chart Wizard – Step 2 of 4
– Chart Source Data box. You just told Chart Wizard what
numbers to place on the X-axis.
You may not have to do this each time you write a graph. Check
to be sure the correct values appear on the X-axis. If they do,
you may skip this step.
Click NEXT.
e. WRITING THE CHART TITLE AND AXES LABELS
Skip (or Tab) down to the Category (X) Axis. We are going to
begin with the X- and Y-axes labels.
1. WRITING THE CATEGORY (X) AXIS
Usually, you should copy the heading from the Table and use it
as the X-axis label. If you are unsure what to write, just ask and
you will be told.
In this graph, the X-axis would be labeled Time (seconds).
Notice that the units appear in parentheses when labeling the
axes.
2. WRITING THE CATEGORY (Y) AXIS
The same rule applies to this axis: copy the appropriate heading
from the table. In this graph, the label of the Y-axis would be
Temperature (oC).
Again, the units appear in parentheses. OPTION-0 produces the
degree sign in Excel.
3. WRITING THE TITLE
Return to Chart Title.
The title should always be what you wrote for the Y- and for the
X-axes, minus the units, using the format “Y vs X.”
In the example we used above, the title would be Temperature
vs. Time.
f. Click FINISH
g. MOVE THE GRAPH
Drag your graph below the table so that you can read both the table and
graph.
h. CHANGING FROM PORTRAIT TO LANDSCAPE
Sometimes you would like to move the paper sideways to give yourself
more room for the graph. To do this, click on an empty cell. Open FILE
- PAGE SETUP - LANDSCAPE - OK. You have just turned your
spreadsheet from a vertical to a horizontal alignment.
i. ADJUSTING THE SIZE AND SHAPE OF THE GRAPH
Click on the white space around the graph. A black line surrounding the
graph should appear.
Adjust the size of the graph by grabbing a corner perimeter box and
dragging it to make the graph larger.
If you grab and drag a box in the middle of the border line, you can
stretch out the length or the height of the graph. This may become
necessary to allow all (or most of the) axis variables to appear.
j. READJUSTING THE LOCATION OF THE LEGEND
Sometimes you will want to drag the graph and fill the space inside the
white box. You can click on the gray graph itself and change its
proportions, and you can drag the legend to a new location, as shown in
the next illustration.
the graph was widened
inside the white box, and
the legend was dragged to
a new location on top of
the graph
k. PRINTING
If you click on the graph, you will print only the graph. But graphs
should always be accompanied by their tables
To print both the table and the graph, click on an empty cell outside of
the graph and the table.
[REMEMBER: type your name in an empty cell so you will know which
graph belongs to you when you go to the printer].
l. IMPROVING THE GRAPH’S APPEARANCE
1. Double click on the gray area inside the graph.
Under FILL, click on a color and click OK.
2. Double click on the graph, again, but this time, click on FILL
EFFECTS under the color choices. Select the GRADIENT tab.
Play around with two colors.
Some words of advice are in order. First, dark colors print out as
dark gray or even black on a black and white printer, and that
could obscure the curve on your graph. If you intend to print
your graph, I suggest that you use only light colors. Second,
fancy colors and other effects might distract from your basic
intent of trying to give understanding to a string of numbers.
While glitz is fun, it may not be wise to use it.
3. Would you like to add a background picture inside of the graph? For
example, maybe you think a picture of a thermometer would be
an appropriate image. Double click on the graph, choose FILL
EFFECTS and open the PICTURE tab. A picture should be
related to the subject of the graph. A picture of your favorite
vacation spot might be confusing when the graph has to do with
the effects of temperature.
4. To change the color of the title’s font, double click on the title. You
can also change the color of the X and Y labels.
5. To change the color of the line, double click on the curve (the line in
the graph) and change its color.
6. Similarly, you can change the color of the data points.
7. Can you change the color of the white field around the graph?
m. TO ERASE A GRAPH
Sometimes it is easier simply to re-write a graph if you make a mistake.
There are two ways to erase a graph. You can click in the white area
around the graph and press the DELETE key or you can press EDIT CLEAR - ALL.
n. TO CREATE TWO Y-AXES
Sometimes, you will have two columns of very different data for the Yaxes. For example, for the homework exercise called DO in the Snake
River, you will be asked to graph both Water Temperature and Dissolved
Oxygen (quite different variables).
To do this, start to graph the data in the usual way, highlighting all three
columns. Prepare the title and the Category (X) axis as usual.
The Value (Y) axis is the heading of the first column of “Y” data in the
table. Click on FINISH.
Refer to the legend to identify the line for the Y-axis that you labeled.
Click on the line of the second Y-axis variable in the graph.
Click: FORMAT - SELECTED DATA SERIES.
Open the AXIS tab and select SECONDARY AXIS
OK
Open CHART - CHART OPTIONS - TITLE.
Type in the name of the heading of the second Y-axis under Second
Value (Y) Axis. CAUTION: be sure you type this name in the correct
location! You do not want this label appearing as a second X-axis label.
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