GRAPHING TECHNIQUES
In most experiments, your data will be a list of measurements that you have made. However, data is hard
to interpret by just looking at the numbers. A graph makes it easier to see relationships between numbers.
Several steps are taken in constructing a graph. (The use of a pencil is suggested.)
1. Turn your graph paper so that the x-axis will always be on the widest part of the paper (landscape
format.)
2. The x-axis is the independent variable (factor that is purposely changed in a set interval in an
experiment and y-axis is the dependent variable (factor changed or determined by changes in the
independent variable.
3. Label the x- and y-axis and include units. Example: time (sec), length (cm)
4. Start both x- and y-axis from 0.
5. Maximize your paper, ie., make your graph as BIG as possible (use the whole page). Adjust x and y
numerical values to allow for maximum space. DO NOT use breaks.
6. Plot data points using small points (dots).
7. After plotting the data, the points are connected by a smooth line/curve. THIS IS NOT THE SAME
AS CONNECTING THE DOTS. The curve may or may not be a straight line, but it always shows
the best “picture” or relationship of the data. The best fit curve comes as close as possible to all the
plotted points but does not necessarily have to touch all, or even any, of these points.
a. Do not use pen to draw the best fit line/curve.
b. Do not sketch using multiple lines.
c. Use a ruler if the relationship is a straight line.
d. If a data point is “off” the curve, circle it on the graph and ignore it when drawing the best fit
curve.
8. Title your graph and be specific.
(Example: Affect of temperature on reaction rate, not Temperature vs. time.
9. Extrapolate means to estimate data beyond the given data points. This means you may need to draw a
dotted line and extend your graph to get “extrapolated” data.
10. No computer graphs.
TRY IT!
1. Graph the data below using the techniques mentioned above.
2. Extrapolate your graph to 185C.
3. Use saturation temperature as the independent variable.
Saturation Temperature (C)
15
30
45
60
75
90
105
120
185
Solubility (g/100g H2O)
10.0
14.0
21.0
29.0
39.0
49.0
62.0
70.0
??
Questions (put your answers on the back of your graph):
1. Is this a direct or inverse proportionality?
2. Using your graph, what would you predict the solubility to be at 100C?
This rubric is used to verify specific tasks performed to construct a line graph. Reduced or no points will
be awarded if the task is incomplete or missing.

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The independent variable (x- axis) is on the widest part of the paper
Each axis is clearly and neatly labeled including the units in which each variable is measured
Has a descriptive title
Both axes start at 0 and are scaled and numbered appropriately with no breaks (no awkward jumps
in values)
The scale on both axes is such that the graph covers most of the page
Neat and legible with each data point indicated by an obvious, but not overly large dot
The line plotted for the graph starts at (0,0) and is neat and appropriate (most graphs should be
drawn as “best-fit” lines or curves.)
Extrapolation is carefully done to extend the line of the graph with a dotted line beyond given data
points.
Have correct answers to interpretive questions and labeled with correct units
Name ________________________________
SCORE: _______/ 15
This rubric is used to verify specific tasks performed to construct a line graph. Reduced or no points will
be awarded if the task is incomplete or missing.









The independent variable (x- axis) is on the widest part of the paper
(____/1 pt)
Each axis is clearly and neatly labeled including the units in which each variable is measured
(____/2 pts)
Has a descriptive title
(____/2 pts)
Both axes start at 0 and are scaled and numbered appropriately with no breaks (no awkward jumps
in values)
(____/2 pts)
The scale on both axes is such that the graph covers most of the page
(____/ 1 pt)
Neat and legible with each data point indicated by an obvious, but not overly large dot (____/1 pt)
The line plotted for the graph starts at (0,0) and is neat and appropriate (most graphs should be
drawn as “best-fit” lines or curves.)
(____/2 pts)
Extrapolation is carefully done to extend the line of the graph with a dotted line beyond given data
points.
(____/2 pts)
Have correct answers to interpretive questions and labeled with correct units
(____/2 pts)
Name ________________________________
SCORE: _______/ 15
This rubric is used to verify specific tasks performed to construct a line graph. Reduced or no points will
be awarded if the task is incomplete or missing.









The independent variable (x- axis) is on the widest part of the paper
(____/1 pt)
Each axis is clearly and neatly labeled including the units in which each variable is measured
(____/2 pts)
Has a descriptive title
(____/2 pts)
Both axes start at 0 and are scaled and numbered appropriately with no breaks (no awkward jumps
in values)
(____/2 pts)
The scale on both axes is such that the graph covers most of the page
(____/ 1 pt)
Neat and legible with each data point indicated by an obvious, but not overly large dot (____/1 pt)
The line plotted for the graph starts at (0,0) and is neat and appropriate (most graphs should be
drawn as “best-fit” lines or curves.)
(____/2 pts)
Extrapolation is carefully done to extend the line of the graph with a dotted line beyond given data
points.
(____/2 pts)
Have correct answers to interpretive questions and labeled with correct units
(____/2 pts)