Graphing Module I
UCCS Physics Labs
Table of Contents
Graphs
Graph Format
FYI
FYI
Human thigh bones are stronger than concrete!
Graphing Module I - 1
1
2
Graphs (the unsung hero of all scientists)
Graphs are something people use everyday. So why is it when graphs are
mentioned in lecture or lab class a muffled groan is heard? We use graphs everyday to:
•
Chart a persons weight
•
Follow the trends in the stock market
•
Chart temperatures
•
Can you think of any more examples?
The ability to graph your data gives you an extremely powerful and useful tool.
Graphs make it easy to visualize large amounts of information with a single glance. It
also gives you the functional relationship (trends) between variables. The only difference
between everyday graphs and the ones used by scientists is that scientific graphs squeeze
more information from a graph.
Constructing a graph
Beyond being a picture of all your data in a single glance, a graph can tell you:
•
If your data is valid
•
If your data contains errors and/or anomalies
•
If your data corresponds to an expected result
•
If your data shows a relationship between the two quantities measured
(2D plots)
•
Predicted results outside the limits of the experiment
Graphing Module I - 2
Graphing Format
All graphs should contain the following
•
A Title –
Give your graphs a title describing what the graph represents.
•
Labeled Axes –
Each axis represents a measured value. Label each axis, indicating what
measured value is being represented. Include the units of each axis!
•
Scaling data –
You will want to make the division spacing of your axis large enough so
that the graph will fill at least half of a page.
Hint: scan your data for the highest and lowest values. Start your
axis with the lowest value and end the axis with the highest
value. The length of the axis should cover at least half of a page.
Graphing Module I - 3
The Good, the Bad and the Ugly - Some Graphing Examples
The first graph is an example of the required format. The graph is well labeled
and easy to read. At a glance, it is easy to understand what this graph represents. The
data is nicely spaced within the graph so that a trend can be easily spotted. The axes are
labeled and the units are given.
The Good!
Distance traveled by a car vs. the time traveled
(car at constant velocity).
70
60
Note: Data table should NOT
be located within a graph.
Placed here for clarity only.
Distance (meters)
50
Data
40
Time (s)
1
2
3
4
5
6
7
30
20
10
0
1
2
3
4
5
6
Time (sec.)
Graphing Module I - 4
7
8
Distance (m)
11
19
32
40
49
62
71
The Bad and The Ugly
What does this graph
represent?
Can you tell the purpose
of this experiment?
This data is packed in too tight.
It makes the graph almost
useless. It is also difficult to get
any information regarding trends.
What does this axis represent?
What are its units of this measurement?
Problems with this graph
•
No title explaining the purpose of the graph.
•
The graph needs to be bigger.
•
The data needs to be more spread out to fill in the graph.
•
Axis needs to be labeled and the units given.
Graphing Module I - 5