Making scientific graphs with
Microsoft Excel		 Making scientific graphs on
graph paper

Graphs are a useful tool in science. The visual characteristics of a graph make trends in data easy to see. One of the most valuable uses for graphs is to "predict" data that is not measured on the graph.

  • Extrapolate: extending the graph, along the same slope, above or below measured data.
  • Interpolate: predicting data between two measured points on the graph.

How To Construct a Line Graph On Paper
Step What To Do How To Do It
1 Identify the variables
  1. Independent Variable -
    (controlled by the experimentor)
    • Goes on the X axis (horizontal)
    • Should be on the left side of a data table.
  2. Dependent Variable -
    (changes with the independent variable)
    • Goes on the Y axis (vertical)
    • Should be on the right side of a data table.
2 Determine the variable range.
  1. Subtract the lowest data value from the highest data value.
  2. Do each variable separately.
3 Determine the scale of the graph.
  1. Determine a scale,
    (the numerical value for each square),
    that best fits the range of each variable.
  2. Spread the graph to use MOST of the available space.
4 Number and label each axis.
  • This tells what data the lines on your graph represent.
5 Plot the data points.
  1. Plot each data value on the graph with a dot.
  2. You can put the data number by the dot, if it does not clutter your graph.
6 Draw the graph.
  1. Draw a curve or a line that best fits the data points.
  2. Most graphs of experimental data are not drawn as "connect-the-dots".
7 Title the graph.
  1. Your title should clearly tell what the graph is about.
  2. If your graph has more than one set of data, provide a "key" to identify the different lines.

Graphing resources:

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