Today, you will learn how to:
Make a constant value a cell instead of a number
Create a scatter plot for your data
Insert a trendline into your graph
Format your graph with gridlines and axes titles
First, you will enter your given set of data into an Excel
spreadsheet.
Make sure you put your mass value in it’s own cell. We
will use this value as a constant in your equation.
Usually, when you copy a formula, it will change the
row/column as you copy the formula.
To prevent this, put a $ in front of both the column letter
and the row number (ex. $A$4)
Enter the force equation using the mass from the cell
instead of typing the number
As you can see in the picture below, the $ does not let
the cell with the $ change:
To calculate an average in Excel, you will want to type
AVERAGE(), and put the cells you would like to
average inside the parentheses.
Excel also allows us to create graphs for data analysis
To graph, start by highlighting two columns of data
Click on the “Insert” tab, then click the scatterplot button.
The first column you highlight will appear on the
horizontal axis of the graph.
The second column you highlight will appear on the
vertical axis of the graph
For the majority of your graphs, you will want to graph
points, not lines.
Your graph should look like this:
You should delete both instances of “Force (N)” from the
graph, since you will put titles under graphs. (Only delete
the title if you have multiple sets of data on a single graph)
Click on your graph
The “Chart Tools” menu will show
Select the “Layout Tab”
Click on the “Axes Titles” button to add horizontal and
vertical axes titles.
For the horizontal axis, your title should read
“Radius(m)”
For the vertical axis, your title should read “Force (N)”
You will also want to add both major & minor gridlines for
both the horizontal and vertical axes
In the same menu, click the “Gridlines” button, then insert
the appropriate gridlines on your graph
Your graph should now look like this:
Generally, when we take a set of data, we like to find an
equation to model the data.
To add a trendline, right click on a data point on your
graph. Select “Add Trendline”.
A menu will pop up. For this
graph, you will select:
A linear fit
Show equation on chart
Do NOT select the “Set
Intercept” button.
Select close and move your equation so it can easily be
read.
Your graph should look like this:
Your trendline is given as a generic y vs. x graph, since
Excel does not know the variables you used to produce
the graph.
When you present your data in your lab report, you
should replace the y and x with the appropriate
variables for your experiment.
Example F = 34.12r + 0.562
Your graph should have a white background when you
submit your report.
This should be a default setting on Office 2007. However if
you have a grey or another color background, you need to
change the color to white.
You can do this using the “Design” tab under the “Chart
Tools” menu. Select a design with a white background.
Just like your data table in your spreadsheet, you will
want to copy and paste your graph into a Word file
when you write your lab report.
Make sure your graph utilizes as much space as
possible (~ ½ page) by clicking on a corner and
dragging the image so it is larger.
Make sure you type and center a title below the graph.
Figure 1 – A graph of centripetal force vs. the radius of
the hanging mass.
The End
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