1
NORTHERN ILLINOIS UNIVERSITY
PHYSICS DEPARTMENT
Physics 253 – Fundamental Physics Mechanics
Plotting with Excel: A Primer
The best way to present tabulated data is with a table. Excel offers a useful tool for
plotting information. Open up the Excel 2007 application. Label column E time and the
column F position. (Be sure to use these columns as the directions that follow might be
different – particularly if columns A and B are used!) In the time column, insert the
values from 1 to 10 in steps of 1. In the position column insert the square of the time
values: 1, 4, 9, 16, 25, 36, 49, 64, 81, and 100. This example shows data for an object that
is accelerating – you can tell because the position increases as the square of the time.
To plot these data go to the insert tab, select scatter in the Charts section, and then click
on the scatter icon which has no curves. You will get an empty chart region. Then select
select data in the Data section. You should get a dialog box. Click on the Add button.
Type “Position versus Time” in the box Series Name.
For the Series X values, click on the selection tool (the far right icon which has the red
diagonal arrow). You will get another dialog box.
Then select the points for the horizontal axis by highlighting the data in the time column.
Then press return (or enter). For the Series Y values, click on the selection tool. Then
select the points for the vertical axis by highlighting the data in the position column.
Then press return (or enter). You should get the following plot. Enter OK twice to clear
the dialog boxes.
2
(If you are seeing a curve plotted through the data points, select Change Chart Type in
the Type section. Select the scatter with only markers icon in the XY (Scatter) section.
Press ok. Data points should have no curve or line connecting the points.) Error bars will
be discussed shortly.
For the following two paragraphs be sure the graph has been selected by left clicking on
the graph.
Go to the topmost layout tab and select the axis titles in the Labels section. Properly
label the x and y-axes as “Time (sec)” and “Position (m)” always making certain you
write out their units. Give the chart the title “Position versus Time” by selecting the
chart title in the Labels section. Click on error bars in the Analysis section, select more
error bars options, and set the percentage to 15% (this makes the error bars easily
observable). If you get horizontal error bars, click on one of the longest horizontal error
bar line segments which will select all horizontal error bars (make certain not to select the
vertical error bar line segment), and press backspace (or delete). Plots made in this way
can be cut and pasted into your lab report in Word.
To make multiple plots, add a new time and position column as shown below. Select the
design tab, then click on select data in the Data section. Click on the add button and
type in a series name (call it position2). In the Series X values field, click on the far right
data selection icon and then select the x-data in the time2 column, then press return. In
the Series Y values field, click on the far right data selection icon and then select the ydata in the position2 column, then press return. This should produce the two plots on one
graph. Enter OK twice to clear the dialog boxes.
3
A linear regression is the formal name for a fit to the data which minimizes the distance between
the final or best curve and the data points. To perform a linear regression fit to the parabola,
enter data as shown in the figure below into your excel spreadsheet. Create a plot of your data.
Then go to the layout tab and select trendline in the Analysis section. Select more trendline
options, then select polynomial and set the order to 2 (a parabola). Check the box display
equation on chart. For the trendline name, select the custom button and type in Parabolic Fit.
Then press the close button. You should be able to reproduce the graph shown below.